Arthroplasty/Joint Replacement

Total hip arthroplasty (THA) has revolutionized the practice of orthopedic surgery. The number of primary THAs performed in the United States alone is predicted to rise to 572,000 per year by 2030.¹ Increasing demand requires a tighter focus on cost-effectiveness, particularly with regard to expensive postoperative complications. Trunnionosis and taper corrosion have recently emerged as problems in THA.^2-7 No longer restricted to metal-on-metal bearings, these phenomena now affect an increasing number of metal-on-polyethylene THAs and are exacerbated by modularity.⁸ The emergence of these complications adds complexity to the diagnostic algorithm in patients who present with painful THAs. Furthermore, the diagnosis of either trunnionosis or taper corrosion calls for revision surgery. In response to the increase in these complications, a group of orthopedic professional societies developed an algorithm for managing suspected metal toxicity issues.⁹ However, increases in toxicity and patient morbidity, and the added costs of toxicity surveillance and revision surgery, will place a substantial economic burden on many health systems at a time when policy makers are implementing substantial changes to health delivery in an effort to contain costs while improving patient outcomes.

Although they are more expensive than cobalt-chrome heads, ceramic femoral heads make metal toxicity a nonissue and eliminate the need for toxicity surveillance protocols. Furthermore, ceramic femoral heads are thought to have longevity advantages (this relationship needs to be confirmed in long-term studies).

In this article, we provide a theoretical framework for debating whether use of ceramic femoral heads in all THA patients could represent a more cost-effective option over the long term.

Materials and Methods

Guidelines for the diagnostic algorithm for painful THA with suspected metal toxicity were obtained from a recent orthopedic professional society consensus statement.⁹ The cost of this work-up was obtained from the finance department at our institution (Table 1).

All costs are uniform across our health system, from rural primary care clinics to tertiary referral centers. The aspects of clinical care analyzed in this study included imaging tests (metal artifact reduction sequence magnetic resonance imaging [MARS-MRI], ultrasonography [US], radiography); serum tests (C-reactive protein, erythrocyte sedimentation rate, cobalt, chrome); aspiration tests (synovial fluid aspiration, manual cell count and differential, synovial fluid culture and sensitivity testing); clinical appointments and procedures (established patient visit, revision THA with 3-day inpatient stay) (Table 1).

We created 2 metrics to analyze the cost difference between ceramic and cobalt-chrome femoral heads. The first metric was “ceramic surplus,” the extra cost of a ceramic femoral head above that of a cobalt-chrome femoral head, and the second was “maximum ceramic surplus,” the ceramic surplus cutoff value for which using ceramic femoral heads in all patients becomes more cost-effective than using cobalt-chrome heads.

Ceramic surplus was determined for 3 different practice settings (high-volume academic, high-volume private, low-volume private) using data from 2 implant companies (DePuy, Biomet) (Table 2).

The cost of a metal work-up was determined for a single round of imaging tests (stratified by MRI and US), serum tests, aspiration tests, and clinic visit. These data were then combined with the cost of revision THA (Table 1) to create a series of maximum ceramic surplus models. In all these simulations, we assumed that about 7% of patients with metal-on-polyethylene THA would present with groin pain 1 to 2 years after surgery,¹⁰ and, working on this assumption, we applied a series of theoretical incidence ratios (12.5%, 25%, 50%) to both the percentage of patients who presented with a painful THA and received a metal toxicity work-up and the percentage of those who received the toxicity work-up and eventually needed revision surgery. For example, in the best-case scenario, the model assumes that 7% of THA patients present with pain and that 12.5% of the painful cohort receives a single work-up for metal toxicity (0.875% of all THAs). The best-case scenario then assumes that 12.5% of patients who receive a work-up for metal toxicity are eventually revised (0.11% of all THAs). By contrast, in the worst-case scenario, the model continues to assume that 7% of THA patients present with pain, but it also assumes that 50% of the painful cohort receives a single work-up for metal toxicity (3.5% of all THAs).

The worst-case scenario then assumes that 50% of patients who receive a work-up for metal toxicity are eventually revised (1.75% of all THAs). As preferences and availability for 3-dimensional imaging differ between centers, the models were stratified by use of MARS-MRI or US. The resulting number in all the simulations was the maximum ceramic surplus (Table 3).

The lowest maximum ceramic surplus values were calculated from the best-case scenario, and the highest from the worst-case scenario. These steps were taken in keeping with the fact that a lower incidence of metal toxicity work-ups and revisions would require the price difference between ceramic and cobalt-chrome heads (ceramic surplus) to be small in order for ceramic heads in all patients to be cost-effective. The inverse is true for a high incidence of metal toxicity work-ups and revisions: A larger price difference between ceramic and cobalt-chrome femoral heads would be tolerable to still be cost-effective.

 

Results

A single metal toxicity work-up cost $5085 with MARS-MRI and $2402 with US (Table 1). Revision THA with a 3-day inpatient stay cost $53,320, and that figure does not include the cost of surgical implants or perioperative medications and devices, all of which have highly variable cost structures (Table 1). Ceramic surplus was as low as $500 in a high-volume academic practice and as high as $1500 in a low-volume private practice (Table 2). Maximum ceramic surplus ranged from $511 to $2044 in the models integrating MARS-MRI and from $488 to $1950 in the models integrating US (Table 3).

Discussion

Trunnionosis, corrosion, and metal toxicity are of increasing concern in hip implants that incorporate a cobalt-chrome femoral head, regardless of the counterpart articulation surface (metal, ceramic, polyethylene).^2-8 In response to the added diagnostic challenge raised by these phenomena, a group of orthopedic professional societies developed an algorithm that can guide surgeons in the management of suspected corrosion or metal toxicity.⁹ In this protocol, toxicity surveillance in conjunction with potential revision surgery for metal-associated complications has the potential to increase patient morbidity and place a significant economic burden on many health systems. Given the recent emergence of trunnionosis, epidemiologic data on this complication are lacking.¹⁰ However, there is a substantial body of evidence showing devastating complications associated with adverse reactions to metal debris.^11-17

Given the potential complications specific to cobalt-chrome femoral heads, we wanted to provide a theoretical framework for debating whether use of ceramic heads in all patients has the potential to be a more cost-effective option over the long term. Ceramic femoral heads are premium implants, certainly more expensive at initial point of care. One study based on a large community registry showed premium implants (eg, ceramic femoral heads) add a surplus averaging $1000.¹⁸ In our investigation, ceramic surplus varied with practice setting, from $500 to $1500. Lower costs were discovered in high-volume practice settings, indicating that a shift to increased use of ceramic femoral heads would likely decrease ceramic surplus for most institutions.

We used a series of simulations to predict maximum ceramic surplus after manipulation of theoretical incidence ratios. The main limitation of this study was our use of 7% as the incidence of painful THA within 1- to 2-year follow-up. This point estimate was derived from a manuscript that to our knowledge provides the most realistic estimate of this complication¹⁰; with use of more complete data in upcoming studies, however, the 7% figure could certainly change. As data are also lacking on the proportion of painful THAs that receive a metal work-up and on the proportion of metal work-ups that indicate revision surgery, we modeled values of 12.5%, 25%, and 50% for each of these metrics to cover a wide range of possibilities.

It is also true the model did not incorporate scenarios to account for the law of unintended consequences, which would caution that using ceramics for all patients may bring a new set of complications. Zirconia ceramic bearings have tended to fracture, with the vast majority of fractures occurring in the liner of ceramic-on-ceramic articulations. Midterm reports and laboratory data suggest this issue has largely been solved with the advent of delta ceramics, a composite containing only a small fraction of zirconia.^19,20 Nevertheless, longer term in vivo data are needed to confirm the stability, longevity, and complication profile of these materials.

A final limitation of the present study is that the cost of a single metal toxicity work-up was based on just one institution. Grossly differing cost structures in other markets could alter the economic risk–benefit analysis we have described. However, we should note that the costs of tests, procedures, and appointments at our institution were uniform across a wide variety of practice settings in multiple regions of the United States, and thus are likely similar to the costs at a majority of practices.

Although our model took some liberties by necessity, it was also quite conservative in many respects. Many patients who undergo surveillance for metal toxicity undergo serial follow-ups; for this analysis, however, we considered the cost of only a single work-up. In addition, our proposed cost of revision surgery accounts only for facility and personnel costs during a 3-day inpatient stay and does not include the costs of implants, perioperative medications and devices, follow-up care, and potentially longer hospital stays or subsequent procedures, all of which can be highly variable and add considerable cost. Had any or all of these factors been incorporated into more complex modeling, the potential economic benefits of ceramic femoral heads would have been significantly greater.

After taking all these factors into account, our model found that maximum ceramic surplus ranged from $488 to $2044, depending on theoretical incidence ratio and imaging modality (Table 3). The lowest maximum ceramic surplus values ($511 for MARS-MRI protocol, $488 for US protocol) were based on the assumption that only 12.5% of patients who present with a painful THA receive a single metal work-up (0.875% of all THAs) and that only 12.5% of those patients are eventually revised (0.11% of all THAs). This outcome suggests ceramic femoral heads could be more cost-effective than cobalt-chrome femoral heads under these conservative projections when considering ceramic surplus is already as low as $500 at some high-volume centers. This figure would likely decline further in parallel with widespread growth in demand. Further study on the epidemiology of trunnionosis, corrosion, and metal toxicity in metal-on-polyethylene THA is needed to evaluate the economic validity of this proposal. Nevertheless, the superior safety profile of ceramic femoral heads with regard to metal toxicity indicates that wholesale use in THAs may in fact provide the most economical option on a societal scale.

Am J Orthop. 2016;45(6):E362-E366. Copyright Frontline Medical Communications Inc. 2016. All rights reserved.

Total hip arthroplasty (THA) has revolutionized the practice of orthopedic surgery. The number of primary THAs performed in the United States alone is predicted to rise to 572,000 per year by 2030.¹ Increasing demand requires a tighter focus on cost-effectiveness, particularly with regard to expensive postoperative complications. Trunnionosis and taper corrosion have recently emerged as problems in THA.^2-7 No longer restricted to metal-on-metal bearings, these phenomena now affect an increasing number of metal-on-polyethylene THAs and are exacerbated by modularity.⁸ The emergence of these complications adds complexity to the diagnostic algorithm in patients who present with painful THAs. Furthermore, the diagnosis of either trunnionosis or taper corrosion calls for revision surgery. In response to the increase in these complications, a group of orthopedic professional societies developed an algorithm for managing suspected metal toxicity issues.⁹ However, increases in toxicity and patient morbidity, and the added costs of toxicity surveillance and revision surgery, will place a substantial economic burden on many health systems at a time when policy makers are implementing substantial changes to health delivery in an effort to contain costs while improving patient outcomes.

Although they are more expensive than cobalt-chrome heads, ceramic femoral heads make metal toxicity a nonissue and eliminate the need for toxicity surveillance protocols. Furthermore, ceramic femoral heads are thought to have longevity advantages (this relationship needs to be confirmed in long-term studies).

In this article, we provide a theoretical framework for debating whether use of ceramic femoral heads in all THA patients could represent a more cost-effective option over the long term.

Materials and Methods

Guidelines for the diagnostic algorithm for painful THA with suspected metal toxicity were obtained from a recent orthopedic professional society consensus statement.⁹ The cost of this work-up was obtained from the finance department at our institution (Table 1).

All costs are uniform across our health system, from rural primary care clinics to tertiary referral centers. The aspects of clinical care analyzed in this study included imaging tests (metal artifact reduction sequence magnetic resonance imaging [MARS-MRI], ultrasonography [US], radiography); serum tests (C-reactive protein, erythrocyte sedimentation rate, cobalt, chrome); aspiration tests (synovial fluid aspiration, manual cell count and differential, synovial fluid culture and sensitivity testing); clinical appointments and procedures (established patient visit, revision THA with 3-day inpatient stay) (Table 1).

We created 2 metrics to analyze the cost difference between ceramic and cobalt-chrome femoral heads. The first metric was “ceramic surplus,” the extra cost of a ceramic femoral head above that of a cobalt-chrome femoral head, and the second was “maximum ceramic surplus,” the ceramic surplus cutoff value for which using ceramic femoral heads in all patients becomes more cost-effective than using cobalt-chrome heads.

Ceramic surplus was determined for 3 different practice settings (high-volume academic, high-volume private, low-volume private) using data from 2 implant companies (DePuy, Biomet) (Table 2).

The cost of a metal work-up was determined for a single round of imaging tests (stratified by MRI and US), serum tests, aspiration tests, and clinic visit. These data were then combined with the cost of revision THA (Table 1) to create a series of maximum ceramic surplus models. In all these simulations, we assumed that about 7% of patients with metal-on-polyethylene THA would present with groin pain 1 to 2 years after surgery,¹⁰ and, working on this assumption, we applied a series of theoretical incidence ratios (12.5%, 25%, 50%) to both the percentage of patients who presented with a painful THA and received a metal toxicity work-up and the percentage of those who received the toxicity work-up and eventually needed revision surgery. For example, in the best-case scenario, the model assumes that 7% of THA patients present with pain and that 12.5% of the painful cohort receives a single work-up for metal toxicity (0.875% of all THAs). The best-case scenario then assumes that 12.5% of patients who receive a work-up for metal toxicity are eventually revised (0.11% of all THAs). By contrast, in the worst-case scenario, the model continues to assume that 7% of THA patients present with pain, but it also assumes that 50% of the painful cohort receives a single work-up for metal toxicity (3.5% of all THAs).

The worst-case scenario then assumes that 50% of patients who receive a work-up for metal toxicity are eventually revised (1.75% of all THAs). As preferences and availability for 3-dimensional imaging differ between centers, the models were stratified by use of MARS-MRI or US. The resulting number in all the simulations was the maximum ceramic surplus (Table 3).

The lowest maximum ceramic surplus values were calculated from the best-case scenario, and the highest from the worst-case scenario. These steps were taken in keeping with the fact that a lower incidence of metal toxicity work-ups and revisions would require the price difference between ceramic and cobalt-chrome heads (ceramic surplus) to be small in order for ceramic heads in all patients to be cost-effective. The inverse is true for a high incidence of metal toxicity work-ups and revisions: A larger price difference between ceramic and cobalt-chrome femoral heads would be tolerable to still be cost-effective.

 

Results

A single metal toxicity work-up cost $5085 with MARS-MRI and $2402 with US (Table 1). Revision THA with a 3-day inpatient stay cost $53,320, and that figure does not include the cost of surgical implants or perioperative medications and devices, all of which have highly variable cost structures (Table 1). Ceramic surplus was as low as $500 in a high-volume academic practice and as high as $1500 in a low-volume private practice (Table 2). Maximum ceramic surplus ranged from $511 to $2044 in the models integrating MARS-MRI and from $488 to $1950 in the models integrating US (Table 3).

Discussion

Trunnionosis, corrosion, and metal toxicity are of increasing concern in hip implants that incorporate a cobalt-chrome femoral head, regardless of the counterpart articulation surface (metal, ceramic, polyethylene).^2-8 In response to the added diagnostic challenge raised by these phenomena, a group of orthopedic professional societies developed an algorithm that can guide surgeons in the management of suspected corrosion or metal toxicity.⁹ In this protocol, toxicity surveillance in conjunction with potential revision surgery for metal-associated complications has the potential to increase patient morbidity and place a significant economic burden on many health systems. Given the recent emergence of trunnionosis, epidemiologic data on this complication are lacking.¹⁰ However, there is a substantial body of evidence showing devastating complications associated with adverse reactions to metal debris.^11-17

Given the potential complications specific to cobalt-chrome femoral heads, we wanted to provide a theoretical framework for debating whether use of ceramic heads in all patients has the potential to be a more cost-effective option over the long term. Ceramic femoral heads are premium implants, certainly more expensive at initial point of care. One study based on a large community registry showed premium implants (eg, ceramic femoral heads) add a surplus averaging $1000.¹⁸ In our investigation, ceramic surplus varied with practice setting, from $500 to $1500. Lower costs were discovered in high-volume practice settings, indicating that a shift to increased use of ceramic femoral heads would likely decrease ceramic surplus for most institutions.

We used a series of simulations to predict maximum ceramic surplus after manipulation of theoretical incidence ratios. The main limitation of this study was our use of 7% as the incidence of painful THA within 1- to 2-year follow-up. This point estimate was derived from a manuscript that to our knowledge provides the most realistic estimate of this complication¹⁰; with use of more complete data in upcoming studies, however, the 7% figure could certainly change. As data are also lacking on the proportion of painful THAs that receive a metal work-up and on the proportion of metal work-ups that indicate revision surgery, we modeled values of 12.5%, 25%, and 50% for each of these metrics to cover a wide range of possibilities.

It is also true the model did not incorporate scenarios to account for the law of unintended consequences, which would caution that using ceramics for all patients may bring a new set of complications. Zirconia ceramic bearings have tended to fracture, with the vast majority of fractures occurring in the liner of ceramic-on-ceramic articulations. Midterm reports and laboratory data suggest this issue has largely been solved with the advent of delta ceramics, a composite containing only a small fraction of zirconia.^19,20 Nevertheless, longer term in vivo data are needed to confirm the stability, longevity, and complication profile of these materials.

A final limitation of the present study is that the cost of a single metal toxicity work-up was based on just one institution. Grossly differing cost structures in other markets could alter the economic risk–benefit analysis we have described. However, we should note that the costs of tests, procedures, and appointments at our institution were uniform across a wide variety of practice settings in multiple regions of the United States, and thus are likely similar to the costs at a majority of practices.

Although our model took some liberties by necessity, it was also quite conservative in many respects. Many patients who undergo surveillance for metal toxicity undergo serial follow-ups; for this analysis, however, we considered the cost of only a single work-up. In addition, our proposed cost of revision surgery accounts only for facility and personnel costs during a 3-day inpatient stay and does not include the costs of implants, perioperative medications and devices, follow-up care, and potentially longer hospital stays or subsequent procedures, all of which can be highly variable and add considerable cost. Had any or all of these factors been incorporated into more complex modeling, the potential economic benefits of ceramic femoral heads would have been significantly greater.

After taking all these factors into account, our model found that maximum ceramic surplus ranged from $488 to $2044, depending on theoretical incidence ratio and imaging modality (Table 3). The lowest maximum ceramic surplus values ($511 for MARS-MRI protocol, $488 for US protocol) were based on the assumption that only 12.5% of patients who present with a painful THA receive a single metal work-up (0.875% of all THAs) and that only 12.5% of those patients are eventually revised (0.11% of all THAs). This outcome suggests ceramic femoral heads could be more cost-effective than cobalt-chrome femoral heads under these conservative projections when considering ceramic surplus is already as low as $500 at some high-volume centers. This figure would likely decline further in parallel with widespread growth in demand. Further study on the epidemiology of trunnionosis, corrosion, and metal toxicity in metal-on-polyethylene THA is needed to evaluate the economic validity of this proposal. Nevertheless, the superior safety profile of ceramic femoral heads with regard to metal toxicity indicates that wholesale use in THAs may in fact provide the most economical option on a societal scale.

Am J Orthop. 2016;45(6):E362-E366. Copyright Frontline Medical Communications Inc. 2016. All rights reserved.

Total hip arthroplasty (THA) has revolutionized the practice of orthopedic surgery. The number of primary THAs performed in the United States alone is predicted to rise to 572,000 per year by 2030.¹ Increasing demand requires a tighter focus on cost-effectiveness, particularly with regard to expensive postoperative complications. Trunnionosis and taper corrosion have recently emerged as problems in THA.^2-7 No longer restricted to metal-on-metal bearings, these phenomena now affect an increasing number of metal-on-polyethylene THAs and are exacerbated by modularity.⁸ The emergence of these complications adds complexity to the diagnostic algorithm in patients who present with painful THAs. Furthermore, the diagnosis of either trunnionosis or taper corrosion calls for revision surgery. In response to the increase in these complications, a group of orthopedic professional societies developed an algorithm for managing suspected metal toxicity issues.⁹ However, increases in toxicity and patient morbidity, and the added costs of toxicity surveillance and revision surgery, will place a substantial economic burden on many health systems at a time when policy makers are implementing substantial changes to health delivery in an effort to contain costs while improving patient outcomes.

Although they are more expensive than cobalt-chrome heads, ceramic femoral heads make metal toxicity a nonissue and eliminate the need for toxicity surveillance protocols. Furthermore, ceramic femoral heads are thought to have longevity advantages (this relationship needs to be confirmed in long-term studies).

In this article, we provide a theoretical framework for debating whether use of ceramic femoral heads in all THA patients could represent a more cost-effective option over the long term.

Materials and Methods

Guidelines for the diagnostic algorithm for painful THA with suspected metal toxicity were obtained from a recent orthopedic professional society consensus statement.⁹ The cost of this work-up was obtained from the finance department at our institution (Table 1).

All costs are uniform across our health system, from rural primary care clinics to tertiary referral centers. The aspects of clinical care analyzed in this study included imaging tests (metal artifact reduction sequence magnetic resonance imaging [MARS-MRI], ultrasonography [US], radiography); serum tests (C-reactive protein, erythrocyte sedimentation rate, cobalt, chrome); aspiration tests (synovial fluid aspiration, manual cell count and differential, synovial fluid culture and sensitivity testing); clinical appointments and procedures (established patient visit, revision THA with 3-day inpatient stay) (Table 1).

We created 2 metrics to analyze the cost difference between ceramic and cobalt-chrome femoral heads. The first metric was “ceramic surplus,” the extra cost of a ceramic femoral head above that of a cobalt-chrome femoral head, and the second was “maximum ceramic surplus,” the ceramic surplus cutoff value for which using ceramic femoral heads in all patients becomes more cost-effective than using cobalt-chrome heads.

Ceramic surplus was determined for 3 different practice settings (high-volume academic, high-volume private, low-volume private) using data from 2 implant companies (DePuy, Biomet) (Table 2).

The cost of a metal work-up was determined for a single round of imaging tests (stratified by MRI and US), serum tests, aspiration tests, and clinic visit. These data were then combined with the cost of revision THA (Table 1) to create a series of maximum ceramic surplus models. In all these simulations, we assumed that about 7% of patients with metal-on-polyethylene THA would present with groin pain 1 to 2 years after surgery,¹⁰ and, working on this assumption, we applied a series of theoretical incidence ratios (12.5%, 25%, 50%) to both the percentage of patients who presented with a painful THA and received a metal toxicity work-up and the percentage of those who received the toxicity work-up and eventually needed revision surgery. For example, in the best-case scenario, the model assumes that 7% of THA patients present with pain and that 12.5% of the painful cohort receives a single work-up for metal toxicity (0.875% of all THAs). The best-case scenario then assumes that 12.5% of patients who receive a work-up for metal toxicity are eventually revised (0.11% of all THAs). By contrast, in the worst-case scenario, the model continues to assume that 7% of THA patients present with pain, but it also assumes that 50% of the painful cohort receives a single work-up for metal toxicity (3.5% of all THAs).

The worst-case scenario then assumes that 50% of patients who receive a work-up for metal toxicity are eventually revised (1.75% of all THAs). As preferences and availability for 3-dimensional imaging differ between centers, the models were stratified by use of MARS-MRI or US. The resulting number in all the simulations was the maximum ceramic surplus (Table 3).

The lowest maximum ceramic surplus values were calculated from the best-case scenario, and the highest from the worst-case scenario. These steps were taken in keeping with the fact that a lower incidence of metal toxicity work-ups and revisions would require the price difference between ceramic and cobalt-chrome heads (ceramic surplus) to be small in order for ceramic heads in all patients to be cost-effective. The inverse is true for a high incidence of metal toxicity work-ups and revisions: A larger price difference between ceramic and cobalt-chrome femoral heads would be tolerable to still be cost-effective.

 

Results

A single metal toxicity work-up cost $5085 with MARS-MRI and $2402 with US (Table 1). Revision THA with a 3-day inpatient stay cost $53,320, and that figure does not include the cost of surgical implants or perioperative medications and devices, all of which have highly variable cost structures (Table 1). Ceramic surplus was as low as $500 in a high-volume academic practice and as high as $1500 in a low-volume private practice (Table 2). Maximum ceramic surplus ranged from $511 to $2044 in the models integrating MARS-MRI and from $488 to $1950 in the models integrating US (Table 3).

Discussion

Trunnionosis, corrosion, and metal toxicity are of increasing concern in hip implants that incorporate a cobalt-chrome femoral head, regardless of the counterpart articulation surface (metal, ceramic, polyethylene).^2-8 In response to the added diagnostic challenge raised by these phenomena, a group of orthopedic professional societies developed an algorithm that can guide surgeons in the management of suspected corrosion or metal toxicity.⁹ In this protocol, toxicity surveillance in conjunction with potential revision surgery for metal-associated complications has the potential to increase patient morbidity and place a significant economic burden on many health systems. Given the recent emergence of trunnionosis, epidemiologic data on this complication are lacking.¹⁰ However, there is a substantial body of evidence showing devastating complications associated with adverse reactions to metal debris.^11-17

Given the potential complications specific to cobalt-chrome femoral heads, we wanted to provide a theoretical framework for debating whether use of ceramic heads in all patients has the potential to be a more cost-effective option over the long term. Ceramic femoral heads are premium implants, certainly more expensive at initial point of care. One study based on a large community registry showed premium implants (eg, ceramic femoral heads) add a surplus averaging $1000.¹⁸ In our investigation, ceramic surplus varied with practice setting, from $500 to $1500. Lower costs were discovered in high-volume practice settings, indicating that a shift to increased use of ceramic femoral heads would likely decrease ceramic surplus for most institutions.

We used a series of simulations to predict maximum ceramic surplus after manipulation of theoretical incidence ratios. The main limitation of this study was our use of 7% as the incidence of painful THA within 1- to 2-year follow-up. This point estimate was derived from a manuscript that to our knowledge provides the most realistic estimate of this complication¹⁰; with use of more complete data in upcoming studies, however, the 7% figure could certainly change. As data are also lacking on the proportion of painful THAs that receive a metal work-up and on the proportion of metal work-ups that indicate revision surgery, we modeled values of 12.5%, 25%, and 50% for each of these metrics to cover a wide range of possibilities.

It is also true the model did not incorporate scenarios to account for the law of unintended consequences, which would caution that using ceramics for all patients may bring a new set of complications. Zirconia ceramic bearings have tended to fracture, with the vast majority of fractures occurring in the liner of ceramic-on-ceramic articulations. Midterm reports and laboratory data suggest this issue has largely been solved with the advent of delta ceramics, a composite containing only a small fraction of zirconia.^19,20 Nevertheless, longer term in vivo data are needed to confirm the stability, longevity, and complication profile of these materials.

A final limitation of the present study is that the cost of a single metal toxicity work-up was based on just one institution. Grossly differing cost structures in other markets could alter the economic risk–benefit analysis we have described. However, we should note that the costs of tests, procedures, and appointments at our institution were uniform across a wide variety of practice settings in multiple regions of the United States, and thus are likely similar to the costs at a majority of practices.

Although our model took some liberties by necessity, it was also quite conservative in many respects. Many patients who undergo surveillance for metal toxicity undergo serial follow-ups; for this analysis, however, we considered the cost of only a single work-up. In addition, our proposed cost of revision surgery accounts only for facility and personnel costs during a 3-day inpatient stay and does not include the costs of implants, perioperative medications and devices, follow-up care, and potentially longer hospital stays or subsequent procedures, all of which can be highly variable and add considerable cost. Had any or all of these factors been incorporated into more complex modeling, the potential economic benefits of ceramic femoral heads would have been significantly greater.

After taking all these factors into account, our model found that maximum ceramic surplus ranged from $488 to $2044, depending on theoretical incidence ratio and imaging modality (Table 3). The lowest maximum ceramic surplus values ($511 for MARS-MRI protocol, $488 for US protocol) were based on the assumption that only 12.5% of patients who present with a painful THA receive a single metal work-up (0.875% of all THAs) and that only 12.5% of those patients are eventually revised (0.11% of all THAs). This outcome suggests ceramic femoral heads could be more cost-effective than cobalt-chrome femoral heads under these conservative projections when considering ceramic surplus is already as low as $500 at some high-volume centers. This figure would likely decline further in parallel with widespread growth in demand. Further study on the epidemiology of trunnionosis, corrosion, and metal toxicity in metal-on-polyethylene THA is needed to evaluate the economic validity of this proposal. Nevertheless, the superior safety profile of ceramic femoral heads with regard to metal toxicity indicates that wholesale use in THAs may in fact provide the most economical option on a societal scale.

Am J Orthop. 2016;45(6):E362-E366. Copyright Frontline Medical Communications Inc. 2016. All rights reserved.

Total hip arthroplasty (THA) and total knee arthroplasty (TKA) are among the most effective surgical procedures in modern medicine. Use of primary THA in the United States is projected to increase by 174% by 2030, to 532,000 cases annually, and the estimate for TKA is even greater.¹ Hospital length of stay (LOS) accounts for a significant portion of the overall cost of these procedures. Reducing LOS to limit costs without compromising patient safety, satisfaction, and outcomes remains the goal at all joint arthroplasty centers. Rapid-recovery or fast-track clinical pathways limiting opioid use and emphasizing patient education and early (day-of-surgery) mobilization have been shown to reduce LOS without compromising patient outcomes.^2-5 Factors correlated with LOS after THA include surgical approach, use of multimodal analgesia, obesity, age, and social situations or living conditions.^4,6-10

Our institution recently implemented a protocol in which certified physical therapists provide accelerated (day-of-surgery) physical therapy (PT) for all total joint arthroplasty patients. For the study reported here, we hypothesized that, compared with PT started on postoperative day 1 (POD-1), PT started day of surgery (Day 0) would result in shorter LOS for unilateral primary THA and TKA patients. In addition, we wanted to evaluate any predischarge differences in function, as measured by gait distance, between the groups.

Methods

After obtaining Institutional Review Board approval, we retrospectively evaluated use of the new postoperative protocol (Day 0 PT) for primary THA and TKA patients. We reviewed all cases of primary unilateral THA or TKA performed by a single surgeon over the 12-month period immediately following initiation of the protocol. There were 116 THA cases and 126 TKA cases. Charts were reviewed for patient demographics, intraoperative data, in-hospital course, and PT session notes. Patients who had a PT session at any point on day of surgery were designated the Day 0 group, and patients who had PT starting the next day (POD-1) were designated the Non-Day 0 group. Although the medical records showed that Day 0 PT had been ordered in all cases, not all patients received PT on the day of their surgery; the most common reason was that they returned from postanesthesia care after the physical therapists’ work shift had ended. Another reason was patient noncompliance or unwillingness stemming from the prolonged effects of general anesthesia, diminished mental orientation, excess fatigue, or inadequate pain control. PT sessions after THA and TKA remained consistent over the study period, with twice daily sessions directed at patient mobility, range of motion, and gentle strengthening exercise. PT was performed only with patient consent.

Surgery

A combination of general and spinal anesthesia was used in almost all THA and TKA cases. In <5% of cases, either the patient refused spinal anesthesia, or it was unsuccessful. In addition, tranexamic acid was administered to limit blood loss in all THA and TKA cases. Of the 116 THAs performed over the study period, 3 were excluded (see below). Of the 113 patients included in the study, 88 (77.9%) used a minimally invasive posterolateral approach, 18 (15.9%) a direct anterior approach, and 7 (6.2%) an anterolateral approach. All THAs were performed with conventional instruments and uncemented components. All TKAs were performed with a standard medial parapatellar approach, conventional instruments, and a tourniquet; in each case, the patella was resurfaced, and cemented fixation was used. Drains were not used in any THA or TKA cases. A local anesthetic cocktail (100 mL of 0.25% ropivacaine, 15 mL of 0.5% ropivacaine, and 1 mL of 1:1000 epinephrine) was injected for postoperative analgesia in all THA and TKA cases.

There were 3 important intraoperative findings in the THA Day 0 group: 2 cases of incidental gluteus medius tendon tears requiring repair and 1 case of nondisplaced calcar fracture treated with a cerclage cable. The THA Non-Day 0 group and both TKA groups had no major intraoperative findings.

Physical Therapy

Day-of-surgery PT was ordered for all patients. Patients did not receive formal PT before surgery. The PT protocol consisted of subjective assessment of patient condition, expectations, and goals; lower limb strengthening exercises; and maximum gait training with use of an assistive device as tolerated. Standard hip movement restrictions were ordered for posterolateral approach patients to protect the soft-tissue repair. Continuous passive motion (CPM) was not used during this study period.

Discharge Criteria

Patients were cleared for discharge by a multidisciplinary team using several criteria: no medical condition that would require readmission, intact surgical incision without discharge or concerning erythema, adequate analgesia (oral medications), intact neurovascular examination, and PT goals achieved (independence with bed mobility, transfers, standing balance, and minimum gait distance of 150 feet). Patients who could not be discharged home because of family or occupation issues or because of problems with gait or transfer were referred to skilled nursing or home healthcare. Follow-up for wound assessment and for examination of radiographs and functional range of motion was planned for 2 to 3 weeks after surgery (all patients followed up). Two patients, 1 in the THA Non-Day 0 group and 1 in the TKA Day 0 group, had a mechanical fall 1 day before discharge, but there were no complication-related discharge delays. In addition, there were no readmissions during the first 4 weeks after surgery.

 

Excluded Patients

Of the 116 THA cases, 113 (63 Day 0, 50 Non-Day 0) were analyzed. To establish homogeneity between groups and remove potential confounding factors, we excluded 4 THA patients (all Non-Day 0) from analysis because of medical complications prolonging LOS. In 1 of these cases, the patient developed respiratory insufficiency and myocardial infarction on POD-3, and critical care support was required (LOS, 16 days). In another case, anticoagulation treatment led to the development of a hip hematoma on POD-9 and to treatment (evacuation) in the operating room (LOS, 14 days). The other 2 cases involved exacerbation of dysphagia from preexisting myasthenia gravis (LOS, 5 days) and Ogilvie syndrome, managed conservatively (LOS, 9 days).

Of the 126 TKA cases, 123 (97 Day 0, 26 Non-Day 0) were analyzed. Three TKA patients were excluded because of prolonged hospitalization for medical reasons: One developed a deep vein thrombosis, 1 acquired Clostridium difficile colitis (history of lung transplantation, multiple immunosuppressive drugs), and 1 developed respiratory insufficiency from asthma exacerbation.

Statistical Analysis

Power analysis (G*Power) was used to determine an appropriate sample size for comparison.¹¹ Given a previously published mean LOS after THA of 4 days, the hypothesized mean LOS reducing that by at least 0.5 day to 3.5 days, a significance level set at 5%, a power of test set at 0.95, and an allocation ratio of 1, a minimum of 23 subjects would be needed in each group to attain a statistically significant difference using the nonparametric Mann-Whitney test. The Shapiro-Wilk test was used to assess data normality. Regarding statistical significance, the Mann-Whitney U test was used for non-normally distributed data, the 2-sided Fisher exact test and χ² test for qualitative data and contingency, and the 2-tailed, unpaired, independent-samples Student t test for normally distributed data. Data were analyzed with SPSS Statistics for Windows Version 20 (IBM).

Results

TKA and THA patients had similar demographic profiles, types of anesthesia, operating room and surgery times, surgical approaches, and total number of PT sessions before discharge. Estimated blood loss, however, was significantly (P < .05) higher for Non-Day 0 patients than for Non-Day 0 patients (Table 1).

Mean LOS was 0.1 day shorter for Day 0 patients than for Non-Day 0 patients, the difference was not statistically significant. These groups had equivalent median LOS (2 days) and interquartile range (1).

However, the percentage of THA patients discharged on POD-1 was significantly (P = .041) higher for the Day 0 group (16.1%) than for the Non-Day 0 group (6%) (Figure 1). The overwhelming majority of patients (146/159 in Day 0 group, 70/75 in Non-Day 0 group) were discharged home.

Mean (SD) distance ambulated during first PT session was 2-fold farther (P = .014) for Non-Day 0 patients, 84.1 (10.4) feet, than for Day 0 patients, 42.1 (6.4) feet. On POD-1, mean (SD) gait was significantly (P = .019) longer for Day 0 patients, 162.4 (12.9) feet, than for Non-Day 0 patients, 118 (11.7) feet (Figure 2).

Although mean (SD) gait on POD-2 was longer for Day 0 patients, 189.7 (19.7) feet, than for Non-Day 0 patients, 163 (17.6) feet, the difference was not statistically significant (P = .315).

In TKA patients, although mean (SD) distance ambulated tended to be farther for the Day 0 group than for the Non-Day 0 group—114 (12.3) feet on POD-1 and 176 (15.2) feet on POD-2 for Day 0 vs 94 (22.2) feet on POD-1 and 148 (22.1) feet on POD-2 for Non-Day 0—the differences were not statistically significant. In addition, knee arc of motion during first PT session was statistically significantly (P = .3) higher for Day 0 patients, 69.1° (18.7°), than for Non-Day 0 patients, 61.7° (18.8°).

Statistical analysis revealed no difference in LOS based on surgical approach to the hip: 2.4 days for posterolateral (2.2 days for Day 0 and 2.6 days for Non-Day 0; P = .06); 2.1 days for direct anterior (2.1 days for Day 0 and 2.0 days for Non-Day 0; P = .7); and 2.7 days for anterolateral (3.0 days for Day 0 and 2.6 days for Non-Day 0; P = .6).

Discussion

Protocols for PT after THA and TKA remain unstandardized and largely dependent on institutions and surgeons. Factors permitting successful implementation of accelerated rehabilitation include patient motivation, adequate analgesia, and adequate support by physical therapists.¹² A potential risk associated with accelerated PT after THA is dislocation, which did not occur in any patient in our Day 0 group. Other risks are increased pain and swelling leading to increased risk of falling and bleeding, which were not observed in our cohort. Although Day 0 PT was ordered in all cases in this study, only 55% of THA patients and 79% of TKA patients received PT the same day as their surgery. The delay can be addressed by making physical therapists’ work shifts more flexible for cases that finish later in the day and by providing preoperative education on the importance of day-of-surgery PT. Dr. Incavo and office staff routinely discuss discharge planning with all patients before surgery, but there was no stimulus protocol or communication to discuss or emphasize LOS with patients before surgery, and there was no questionnaire or survey given to assess patient expectations about PT and discharge.

 

Our finding of no statistically significant reduction in mean LOS after implementation of accelerated PT for THA or TKA differs from findings in multiple other reports.^4,5,13-17 Baseline or control group mean LOS tended to be higher in previous studies^3,5,18-23 (3.4-11.4 days) than in our control group (2.5 days) (Table 2).

Although we did not find a statistically significant reduction, a higher percentage of THA Day 0 patients were discharged on POD-1, potentially justifying use of accelerated PT for these patients. Another study reported a similar percentage of patients discharged on POD-1 after accelerated rehabilitation.³ In addition, total number of PT sessions per patient did not differ between groups, limiting the cost-effectiveness of accelerated PT—in contrast to previous reports showing a cost benefit to accelerated PT after THA.²¹ Achieving a meaningful change in LOS after THA and TKA needs to be weighed against potentially compromising patients’ safety, outcomes, and satisfaction. We think use of accelerated PT after THA can facilitate achieving PT goals expeditiously and enhance early postoperative function. Achieving PT goals by POD-1 can help restore patient confidence and allow surgeons to sign off on early but safe discharges. Although accelerated PT may provide some benefit (eg, patient satisfaction, confidence) for TKA patients, there was no demonstrable decrease in the important metric of LOS. PT goals may serve as an alternative to LOS alone in determining the effectiveness of accelerated PT. More objective PT parameters (eg, muscle strength testing) may add more validity to this argument, but we did not use them in this study. The retrospective design of this study is considered a weakness, but we should point out that hospital and surgical protocols were applied uniformly to all patients. Furthermore, we expected longer LOS for our Non-Day 0 patients because we thought they would be less willing to have Day 0 PT. To our surprise, LOS did not differ between the Day 0 and Non-Day 0 groups in both THA and TKA. However, it is important to note that more THA Day 0 patients were discharged on POD-1 (P = .04). The strengths of this study include its simplicity, adequate statistical power, and lack of a difference in patient demographics between groups. In summary, day-of-surgery PT did not change LOS after elective primary THA or TKA. For elective THA, however, same-day PT helped in achieving POD-1 discharge goals.

Conclusion

These results provide useful information for providers who are managing primary THA and TKA cases and seeking continual improvement in postoperative patient care and better resource allocation. Hospitals, particularly those operating in bundled-care environments, are increasingly coming under scrutiny to control costs. Our study results showed that the costs associated with Day 0 PT are justified for THA but not for TKA.

Am J Orthop. 2016;45(6):E337-E342. Copyright Frontline Medical Communications Inc. 2016. All rights reserved.

Total hip arthroplasty (THA) and total knee arthroplasty (TKA) are among the most effective surgical procedures in modern medicine. Use of primary THA in the United States is projected to increase by 174% by 2030, to 532,000 cases annually, and the estimate for TKA is even greater.¹ Hospital length of stay (LOS) accounts for a significant portion of the overall cost of these procedures. Reducing LOS to limit costs without compromising patient safety, satisfaction, and outcomes remains the goal at all joint arthroplasty centers. Rapid-recovery or fast-track clinical pathways limiting opioid use and emphasizing patient education and early (day-of-surgery) mobilization have been shown to reduce LOS without compromising patient outcomes.^2-5 Factors correlated with LOS after THA include surgical approach, use of multimodal analgesia, obesity, age, and social situations or living conditions.^4,6-10

Our institution recently implemented a protocol in which certified physical therapists provide accelerated (day-of-surgery) physical therapy (PT) for all total joint arthroplasty patients. For the study reported here, we hypothesized that, compared with PT started on postoperative day 1 (POD-1), PT started day of surgery (Day 0) would result in shorter LOS for unilateral primary THA and TKA patients. In addition, we wanted to evaluate any predischarge differences in function, as measured by gait distance, between the groups.

Methods

After obtaining Institutional Review Board approval, we retrospectively evaluated use of the new postoperative protocol (Day 0 PT) for primary THA and TKA patients. We reviewed all cases of primary unilateral THA or TKA performed by a single surgeon over the 12-month period immediately following initiation of the protocol. There were 116 THA cases and 126 TKA cases. Charts were reviewed for patient demographics, intraoperative data, in-hospital course, and PT session notes. Patients who had a PT session at any point on day of surgery were designated the Day 0 group, and patients who had PT starting the next day (POD-1) were designated the Non-Day 0 group. Although the medical records showed that Day 0 PT had been ordered in all cases, not all patients received PT on the day of their surgery; the most common reason was that they returned from postanesthesia care after the physical therapists’ work shift had ended. Another reason was patient noncompliance or unwillingness stemming from the prolonged effects of general anesthesia, diminished mental orientation, excess fatigue, or inadequate pain control. PT sessions after THA and TKA remained consistent over the study period, with twice daily sessions directed at patient mobility, range of motion, and gentle strengthening exercise. PT was performed only with patient consent.

Surgery

A combination of general and spinal anesthesia was used in almost all THA and TKA cases. In <5% of cases, either the patient refused spinal anesthesia, or it was unsuccessful. In addition, tranexamic acid was administered to limit blood loss in all THA and TKA cases. Of the 116 THAs performed over the study period, 3 were excluded (see below). Of the 113 patients included in the study, 88 (77.9%) used a minimally invasive posterolateral approach, 18 (15.9%) a direct anterior approach, and 7 (6.2%) an anterolateral approach. All THAs were performed with conventional instruments and uncemented components. All TKAs were performed with a standard medial parapatellar approach, conventional instruments, and a tourniquet; in each case, the patella was resurfaced, and cemented fixation was used. Drains were not used in any THA or TKA cases. A local anesthetic cocktail (100 mL of 0.25% ropivacaine, 15 mL of 0.5% ropivacaine, and 1 mL of 1:1000 epinephrine) was injected for postoperative analgesia in all THA and TKA cases.

There were 3 important intraoperative findings in the THA Day 0 group: 2 cases of incidental gluteus medius tendon tears requiring repair and 1 case of nondisplaced calcar fracture treated with a cerclage cable. The THA Non-Day 0 group and both TKA groups had no major intraoperative findings.

Physical Therapy

Day-of-surgery PT was ordered for all patients. Patients did not receive formal PT before surgery. The PT protocol consisted of subjective assessment of patient condition, expectations, and goals; lower limb strengthening exercises; and maximum gait training with use of an assistive device as tolerated. Standard hip movement restrictions were ordered for posterolateral approach patients to protect the soft-tissue repair. Continuous passive motion (CPM) was not used during this study period.

Discharge Criteria

Patients were cleared for discharge by a multidisciplinary team using several criteria: no medical condition that would require readmission, intact surgical incision without discharge or concerning erythema, adequate analgesia (oral medications), intact neurovascular examination, and PT goals achieved (independence with bed mobility, transfers, standing balance, and minimum gait distance of 150 feet). Patients who could not be discharged home because of family or occupation issues or because of problems with gait or transfer were referred to skilled nursing or home healthcare. Follow-up for wound assessment and for examination of radiographs and functional range of motion was planned for 2 to 3 weeks after surgery (all patients followed up). Two patients, 1 in the THA Non-Day 0 group and 1 in the TKA Day 0 group, had a mechanical fall 1 day before discharge, but there were no complication-related discharge delays. In addition, there were no readmissions during the first 4 weeks after surgery.

 

Excluded Patients

Of the 116 THA cases, 113 (63 Day 0, 50 Non-Day 0) were analyzed. To establish homogeneity between groups and remove potential confounding factors, we excluded 4 THA patients (all Non-Day 0) from analysis because of medical complications prolonging LOS. In 1 of these cases, the patient developed respiratory insufficiency and myocardial infarction on POD-3, and critical care support was required (LOS, 16 days). In another case, anticoagulation treatment led to the development of a hip hematoma on POD-9 and to treatment (evacuation) in the operating room (LOS, 14 days). The other 2 cases involved exacerbation of dysphagia from preexisting myasthenia gravis (LOS, 5 days) and Ogilvie syndrome, managed conservatively (LOS, 9 days).

Of the 126 TKA cases, 123 (97 Day 0, 26 Non-Day 0) were analyzed. Three TKA patients were excluded because of prolonged hospitalization for medical reasons: One developed a deep vein thrombosis, 1 acquired Clostridium difficile colitis (history of lung transplantation, multiple immunosuppressive drugs), and 1 developed respiratory insufficiency from asthma exacerbation.

Statistical Analysis

Power analysis (G*Power) was used to determine an appropriate sample size for comparison.¹¹ Given a previously published mean LOS after THA of 4 days, the hypothesized mean LOS reducing that by at least 0.5 day to 3.5 days, a significance level set at 5%, a power of test set at 0.95, and an allocation ratio of 1, a minimum of 23 subjects would be needed in each group to attain a statistically significant difference using the nonparametric Mann-Whitney test. The Shapiro-Wilk test was used to assess data normality. Regarding statistical significance, the Mann-Whitney U test was used for non-normally distributed data, the 2-sided Fisher exact test and χ² test for qualitative data and contingency, and the 2-tailed, unpaired, independent-samples Student t test for normally distributed data. Data were analyzed with SPSS Statistics for Windows Version 20 (IBM).

Results

TKA and THA patients had similar demographic profiles, types of anesthesia, operating room and surgery times, surgical approaches, and total number of PT sessions before discharge. Estimated blood loss, however, was significantly (P < .05) higher for Non-Day 0 patients than for Non-Day 0 patients (Table 1).

Mean LOS was 0.1 day shorter for Day 0 patients than for Non-Day 0 patients, the difference was not statistically significant. These groups had equivalent median LOS (2 days) and interquartile range (1).

However, the percentage of THA patients discharged on POD-1 was significantly (P = .041) higher for the Day 0 group (16.1%) than for the Non-Day 0 group (6%) (Figure 1). The overwhelming majority of patients (146/159 in Day 0 group, 70/75 in Non-Day 0 group) were discharged home.

Mean (SD) distance ambulated during first PT session was 2-fold farther (P = .014) for Non-Day 0 patients, 84.1 (10.4) feet, than for Day 0 patients, 42.1 (6.4) feet. On POD-1, mean (SD) gait was significantly (P = .019) longer for Day 0 patients, 162.4 (12.9) feet, than for Non-Day 0 patients, 118 (11.7) feet (Figure 2).

Although mean (SD) gait on POD-2 was longer for Day 0 patients, 189.7 (19.7) feet, than for Non-Day 0 patients, 163 (17.6) feet, the difference was not statistically significant (P = .315).

In TKA patients, although mean (SD) distance ambulated tended to be farther for the Day 0 group than for the Non-Day 0 group—114 (12.3) feet on POD-1 and 176 (15.2) feet on POD-2 for Day 0 vs 94 (22.2) feet on POD-1 and 148 (22.1) feet on POD-2 for Non-Day 0—the differences were not statistically significant. In addition, knee arc of motion during first PT session was statistically significantly (P = .3) higher for Day 0 patients, 69.1° (18.7°), than for Non-Day 0 patients, 61.7° (18.8°).

Statistical analysis revealed no difference in LOS based on surgical approach to the hip: 2.4 days for posterolateral (2.2 days for Day 0 and 2.6 days for Non-Day 0; P = .06); 2.1 days for direct anterior (2.1 days for Day 0 and 2.0 days for Non-Day 0; P = .7); and 2.7 days for anterolateral (3.0 days for Day 0 and 2.6 days for Non-Day 0; P = .6).

Discussion

Protocols for PT after THA and TKA remain unstandardized and largely dependent on institutions and surgeons. Factors permitting successful implementation of accelerated rehabilitation include patient motivation, adequate analgesia, and adequate support by physical therapists.¹² A potential risk associated with accelerated PT after THA is dislocation, which did not occur in any patient in our Day 0 group. Other risks are increased pain and swelling leading to increased risk of falling and bleeding, which were not observed in our cohort. Although Day 0 PT was ordered in all cases in this study, only 55% of THA patients and 79% of TKA patients received PT the same day as their surgery. The delay can be addressed by making physical therapists’ work shifts more flexible for cases that finish later in the day and by providing preoperative education on the importance of day-of-surgery PT. Dr. Incavo and office staff routinely discuss discharge planning with all patients before surgery, but there was no stimulus protocol or communication to discuss or emphasize LOS with patients before surgery, and there was no questionnaire or survey given to assess patient expectations about PT and discharge.

 

Our finding of no statistically significant reduction in mean LOS after implementation of accelerated PT for THA or TKA differs from findings in multiple other reports.^4,5,13-17 Baseline or control group mean LOS tended to be higher in previous studies^3,5,18-23 (3.4-11.4 days) than in our control group (2.5 days) (Table 2).

Although we did not find a statistically significant reduction, a higher percentage of THA Day 0 patients were discharged on POD-1, potentially justifying use of accelerated PT for these patients. Another study reported a similar percentage of patients discharged on POD-1 after accelerated rehabilitation.³ In addition, total number of PT sessions per patient did not differ between groups, limiting the cost-effectiveness of accelerated PT—in contrast to previous reports showing a cost benefit to accelerated PT after THA.²¹ Achieving a meaningful change in LOS after THA and TKA needs to be weighed against potentially compromising patients’ safety, outcomes, and satisfaction. We think use of accelerated PT after THA can facilitate achieving PT goals expeditiously and enhance early postoperative function. Achieving PT goals by POD-1 can help restore patient confidence and allow surgeons to sign off on early but safe discharges. Although accelerated PT may provide some benefit (eg, patient satisfaction, confidence) for TKA patients, there was no demonstrable decrease in the important metric of LOS. PT goals may serve as an alternative to LOS alone in determining the effectiveness of accelerated PT. More objective PT parameters (eg, muscle strength testing) may add more validity to this argument, but we did not use them in this study. The retrospective design of this study is considered a weakness, but we should point out that hospital and surgical protocols were applied uniformly to all patients. Furthermore, we expected longer LOS for our Non-Day 0 patients because we thought they would be less willing to have Day 0 PT. To our surprise, LOS did not differ between the Day 0 and Non-Day 0 groups in both THA and TKA. However, it is important to note that more THA Day 0 patients were discharged on POD-1 (P = .04). The strengths of this study include its simplicity, adequate statistical power, and lack of a difference in patient demographics between groups. In summary, day-of-surgery PT did not change LOS after elective primary THA or TKA. For elective THA, however, same-day PT helped in achieving POD-1 discharge goals.

Conclusion

These results provide useful information for providers who are managing primary THA and TKA cases and seeking continual improvement in postoperative patient care and better resource allocation. Hospitals, particularly those operating in bundled-care environments, are increasingly coming under scrutiny to control costs. Our study results showed that the costs associated with Day 0 PT are justified for THA but not for TKA.

Am J Orthop. 2016;45(6):E337-E342. Copyright Frontline Medical Communications Inc. 2016. All rights reserved.

Total hip arthroplasty (THA) and total knee arthroplasty (TKA) are among the most effective surgical procedures in modern medicine. Use of primary THA in the United States is projected to increase by 174% by 2030, to 532,000 cases annually, and the estimate for TKA is even greater.¹ Hospital length of stay (LOS) accounts for a significant portion of the overall cost of these procedures. Reducing LOS to limit costs without compromising patient safety, satisfaction, and outcomes remains the goal at all joint arthroplasty centers. Rapid-recovery or fast-track clinical pathways limiting opioid use and emphasizing patient education and early (day-of-surgery) mobilization have been shown to reduce LOS without compromising patient outcomes.^2-5 Factors correlated with LOS after THA include surgical approach, use of multimodal analgesia, obesity, age, and social situations or living conditions.^4,6-10

Our institution recently implemented a protocol in which certified physical therapists provide accelerated (day-of-surgery) physical therapy (PT) for all total joint arthroplasty patients. For the study reported here, we hypothesized that, compared with PT started on postoperative day 1 (POD-1), PT started day of surgery (Day 0) would result in shorter LOS for unilateral primary THA and TKA patients. In addition, we wanted to evaluate any predischarge differences in function, as measured by gait distance, between the groups.

Methods

After obtaining Institutional Review Board approval, we retrospectively evaluated use of the new postoperative protocol (Day 0 PT) for primary THA and TKA patients. We reviewed all cases of primary unilateral THA or TKA performed by a single surgeon over the 12-month period immediately following initiation of the protocol. There were 116 THA cases and 126 TKA cases. Charts were reviewed for patient demographics, intraoperative data, in-hospital course, and PT session notes. Patients who had a PT session at any point on day of surgery were designated the Day 0 group, and patients who had PT starting the next day (POD-1) were designated the Non-Day 0 group. Although the medical records showed that Day 0 PT had been ordered in all cases, not all patients received PT on the day of their surgery; the most common reason was that they returned from postanesthesia care after the physical therapists’ work shift had ended. Another reason was patient noncompliance or unwillingness stemming from the prolonged effects of general anesthesia, diminished mental orientation, excess fatigue, or inadequate pain control. PT sessions after THA and TKA remained consistent over the study period, with twice daily sessions directed at patient mobility, range of motion, and gentle strengthening exercise. PT was performed only with patient consent.

Surgery

A combination of general and spinal anesthesia was used in almost all THA and TKA cases. In <5% of cases, either the patient refused spinal anesthesia, or it was unsuccessful. In addition, tranexamic acid was administered to limit blood loss in all THA and TKA cases. Of the 116 THAs performed over the study period, 3 were excluded (see below). Of the 113 patients included in the study, 88 (77.9%) used a minimally invasive posterolateral approach, 18 (15.9%) a direct anterior approach, and 7 (6.2%) an anterolateral approach. All THAs were performed with conventional instruments and uncemented components. All TKAs were performed with a standard medial parapatellar approach, conventional instruments, and a tourniquet; in each case, the patella was resurfaced, and cemented fixation was used. Drains were not used in any THA or TKA cases. A local anesthetic cocktail (100 mL of 0.25% ropivacaine, 15 mL of 0.5% ropivacaine, and 1 mL of 1:1000 epinephrine) was injected for postoperative analgesia in all THA and TKA cases.

There were 3 important intraoperative findings in the THA Day 0 group: 2 cases of incidental gluteus medius tendon tears requiring repair and 1 case of nondisplaced calcar fracture treated with a cerclage cable. The THA Non-Day 0 group and both TKA groups had no major intraoperative findings.

Physical Therapy

Day-of-surgery PT was ordered for all patients. Patients did not receive formal PT before surgery. The PT protocol consisted of subjective assessment of patient condition, expectations, and goals; lower limb strengthening exercises; and maximum gait training with use of an assistive device as tolerated. Standard hip movement restrictions were ordered for posterolateral approach patients to protect the soft-tissue repair. Continuous passive motion (CPM) was not used during this study period.

Discharge Criteria

Patients were cleared for discharge by a multidisciplinary team using several criteria: no medical condition that would require readmission, intact surgical incision without discharge or concerning erythema, adequate analgesia (oral medications), intact neurovascular examination, and PT goals achieved (independence with bed mobility, transfers, standing balance, and minimum gait distance of 150 feet). Patients who could not be discharged home because of family or occupation issues or because of problems with gait or transfer were referred to skilled nursing or home healthcare. Follow-up for wound assessment and for examination of radiographs and functional range of motion was planned for 2 to 3 weeks after surgery (all patients followed up). Two patients, 1 in the THA Non-Day 0 group and 1 in the TKA Day 0 group, had a mechanical fall 1 day before discharge, but there were no complication-related discharge delays. In addition, there were no readmissions during the first 4 weeks after surgery.

 

Excluded Patients

Of the 116 THA cases, 113 (63 Day 0, 50 Non-Day 0) were analyzed. To establish homogeneity between groups and remove potential confounding factors, we excluded 4 THA patients (all Non-Day 0) from analysis because of medical complications prolonging LOS. In 1 of these cases, the patient developed respiratory insufficiency and myocardial infarction on POD-3, and critical care support was required (LOS, 16 days). In another case, anticoagulation treatment led to the development of a hip hematoma on POD-9 and to treatment (evacuation) in the operating room (LOS, 14 days). The other 2 cases involved exacerbation of dysphagia from preexisting myasthenia gravis (LOS, 5 days) and Ogilvie syndrome, managed conservatively (LOS, 9 days).

Of the 126 TKA cases, 123 (97 Day 0, 26 Non-Day 0) were analyzed. Three TKA patients were excluded because of prolonged hospitalization for medical reasons: One developed a deep vein thrombosis, 1 acquired Clostridium difficile colitis (history of lung transplantation, multiple immunosuppressive drugs), and 1 developed respiratory insufficiency from asthma exacerbation.

Statistical Analysis

Power analysis (G*Power) was used to determine an appropriate sample size for comparison.¹¹ Given a previously published mean LOS after THA of 4 days, the hypothesized mean LOS reducing that by at least 0.5 day to 3.5 days, a significance level set at 5%, a power of test set at 0.95, and an allocation ratio of 1, a minimum of 23 subjects would be needed in each group to attain a statistically significant difference using the nonparametric Mann-Whitney test. The Shapiro-Wilk test was used to assess data normality. Regarding statistical significance, the Mann-Whitney U test was used for non-normally distributed data, the 2-sided Fisher exact test and χ² test for qualitative data and contingency, and the 2-tailed, unpaired, independent-samples Student t test for normally distributed data. Data were analyzed with SPSS Statistics for Windows Version 20 (IBM).

Results

TKA and THA patients had similar demographic profiles, types of anesthesia, operating room and surgery times, surgical approaches, and total number of PT sessions before discharge. Estimated blood loss, however, was significantly (P < .05) higher for Non-Day 0 patients than for Non-Day 0 patients (Table 1).

Mean LOS was 0.1 day shorter for Day 0 patients than for Non-Day 0 patients, the difference was not statistically significant. These groups had equivalent median LOS (2 days) and interquartile range (1).

However, the percentage of THA patients discharged on POD-1 was significantly (P = .041) higher for the Day 0 group (16.1%) than for the Non-Day 0 group (6%) (Figure 1). The overwhelming majority of patients (146/159 in Day 0 group, 70/75 in Non-Day 0 group) were discharged home.

Mean (SD) distance ambulated during first PT session was 2-fold farther (P = .014) for Non-Day 0 patients, 84.1 (10.4) feet, than for Day 0 patients, 42.1 (6.4) feet. On POD-1, mean (SD) gait was significantly (P = .019) longer for Day 0 patients, 162.4 (12.9) feet, than for Non-Day 0 patients, 118 (11.7) feet (Figure 2).

Although mean (SD) gait on POD-2 was longer for Day 0 patients, 189.7 (19.7) feet, than for Non-Day 0 patients, 163 (17.6) feet, the difference was not statistically significant (P = .315).

In TKA patients, although mean (SD) distance ambulated tended to be farther for the Day 0 group than for the Non-Day 0 group—114 (12.3) feet on POD-1 and 176 (15.2) feet on POD-2 for Day 0 vs 94 (22.2) feet on POD-1 and 148 (22.1) feet on POD-2 for Non-Day 0—the differences were not statistically significant. In addition, knee arc of motion during first PT session was statistically significantly (P = .3) higher for Day 0 patients, 69.1° (18.7°), than for Non-Day 0 patients, 61.7° (18.8°).

Statistical analysis revealed no difference in LOS based on surgical approach to the hip: 2.4 days for posterolateral (2.2 days for Day 0 and 2.6 days for Non-Day 0; P = .06); 2.1 days for direct anterior (2.1 days for Day 0 and 2.0 days for Non-Day 0; P = .7); and 2.7 days for anterolateral (3.0 days for Day 0 and 2.6 days for Non-Day 0; P = .6).

Discussion

Protocols for PT after THA and TKA remain unstandardized and largely dependent on institutions and surgeons. Factors permitting successful implementation of accelerated rehabilitation include patient motivation, adequate analgesia, and adequate support by physical therapists.¹² A potential risk associated with accelerated PT after THA is dislocation, which did not occur in any patient in our Day 0 group. Other risks are increased pain and swelling leading to increased risk of falling and bleeding, which were not observed in our cohort. Although Day 0 PT was ordered in all cases in this study, only 55% of THA patients and 79% of TKA patients received PT the same day as their surgery. The delay can be addressed by making physical therapists’ work shifts more flexible for cases that finish later in the day and by providing preoperative education on the importance of day-of-surgery PT. Dr. Incavo and office staff routinely discuss discharge planning with all patients before surgery, but there was no stimulus protocol or communication to discuss or emphasize LOS with patients before surgery, and there was no questionnaire or survey given to assess patient expectations about PT and discharge.

 

Our finding of no statistically significant reduction in mean LOS after implementation of accelerated PT for THA or TKA differs from findings in multiple other reports.^4,5,13-17 Baseline or control group mean LOS tended to be higher in previous studies^3,5,18-23 (3.4-11.4 days) than in our control group (2.5 days) (Table 2).

Although we did not find a statistically significant reduction, a higher percentage of THA Day 0 patients were discharged on POD-1, potentially justifying use of accelerated PT for these patients. Another study reported a similar percentage of patients discharged on POD-1 after accelerated rehabilitation.³ In addition, total number of PT sessions per patient did not differ between groups, limiting the cost-effectiveness of accelerated PT—in contrast to previous reports showing a cost benefit to accelerated PT after THA.²¹ Achieving a meaningful change in LOS after THA and TKA needs to be weighed against potentially compromising patients’ safety, outcomes, and satisfaction. We think use of accelerated PT after THA can facilitate achieving PT goals expeditiously and enhance early postoperative function. Achieving PT goals by POD-1 can help restore patient confidence and allow surgeons to sign off on early but safe discharges. Although accelerated PT may provide some benefit (eg, patient satisfaction, confidence) for TKA patients, there was no demonstrable decrease in the important metric of LOS. PT goals may serve as an alternative to LOS alone in determining the effectiveness of accelerated PT. More objective PT parameters (eg, muscle strength testing) may add more validity to this argument, but we did not use them in this study. The retrospective design of this study is considered a weakness, but we should point out that hospital and surgical protocols were applied uniformly to all patients. Furthermore, we expected longer LOS for our Non-Day 0 patients because we thought they would be less willing to have Day 0 PT. To our surprise, LOS did not differ between the Day 0 and Non-Day 0 groups in both THA and TKA. However, it is important to note that more THA Day 0 patients were discharged on POD-1 (P = .04). The strengths of this study include its simplicity, adequate statistical power, and lack of a difference in patient demographics between groups. In summary, day-of-surgery PT did not change LOS after elective primary THA or TKA. For elective THA, however, same-day PT helped in achieving POD-1 discharge goals.

Conclusion

These results provide useful information for providers who are managing primary THA and TKA cases and seeking continual improvement in postoperative patient care and better resource allocation. Hospitals, particularly those operating in bundled-care environments, are increasingly coming under scrutiny to control costs. Our study results showed that the costs associated with Day 0 PT are justified for THA but not for TKA.

Am J Orthop. 2016;45(6):E337-E342. Copyright Frontline Medical Communications Inc. 2016. All rights reserved.

After over 4 decades of experience with total knee arthroplasty (TKA), I have learned many lessons regarding surgical technique. These include exposure issues, alignment methods, bone preparation, correction of deformity, and implantation techniques. Most of these lessons have been self-taught, but some have been suggested by or modified from colleague and student interaction. Attribution is given when possible.

The Incision

The skin incision should be marked in flexion rather than extension because the skin moves approximately 1 cm laterally from extension to flexion.¹ This occurs because the tibia internally rotates beneath the skin as the knee is flexed and externally rotates as full extension is achieved. This lateral movement of the skin could bring an incision marked in extension on top of the tibial tubercle when the knee is flexed and may result in pain and dysfunction when the patient attempts to kneel. A review of kneeling ability after TKA showed that most patients are hesitant to kneel initially after their arthroplasty, but gain confidence and improved comfort and ability as their scar matures.²

Exposure

Patellar eversion can be difficult in a markedly obese or ankylosed knee, especially when the patella is difficult to grasp. This is facilitated by the use of a standard patellar clamp that is normally used to compress the patella during component cementation (Figure 1).³

When using this technique, remember to protect the patellar tendon from avulsion by using the techniques described below.

Exposing the Ankylosed Knee and Protecting the Patellar Tendon From Avulsion

A tibial tubercle osteotomy is often recommended in the ankylosed knee but can be avoided by making a short inverted “V” incision in the proximal quadriceps tendon (Figure 2).⁴

This maneuver, along with a smooth 1/8-inchpin in the tibial tubercle, also protects the patellar tendon from avulsing (Figure 3).

The patella can be easily everted and access to the lateral parapatellar scar tissue allows a lateral release to be performed from inside out to further mobilize the knee and enhance exposure. The inverted “V” incision can be closed anatomically, and no modifications of the postoperative physical therapy program are necessary.

Protecting the Soft Tissues During Surgery

Moist wound towels sewn into the joint capsule protect the underlying soft tissues from debris and desiccation during the procedure and will intuitively lower the chance of wound infection from contamination and tissue injury (Figures 4A, 4B).

Since I have done this routinely in both hip and knee arthroplasty over the last 7000 consecutive primary arthroplasties, I have had no operative deep infections. This experience is without the use of antibiotics in the bone cement.

Locating and Coagulating the Lateral Inferior Genicular Vessels

The lateral inferior genicular artery and vein can be easily located and coagulated just outside the posterior rim of the lateral meniscus near the popliteus hiatus. This will minimize both intraoperative and postoperative blood loss.

Determining the Entry Point in the Distal Femur for Intramedullary Alignment Devices

Templating the femoral entry point for insertion of an intramedullary alignment device on a preoperative radiograph will help avoid inadvertent excessive distal femoral valgus resection. This is especially important in valgus knees that have a valgus metaphyseal bow (Figure 5).

In these cases, the entry point must be moved medially and/or the valgus angle chosen must be diminished.

Avoiding Notching of the Anterior Femoral Cortex

Notching the anterior femoral cortex when in-between femoral sizes or when there is a preexisting dysplastic or shallow trochlea (Figure 6)

can be avoided by making the distal femoral resection in an extra 3° of flexion. In most TKA systems, the prosthetic trochlear flange diverges 3° or 4° away from the posterior femoral condyles. If the distal femoral resection is made in an extra 3° of flexion, the femoral component utilized can be anatomically sized off the patient’s posterior femoral condyles and the diverging trochlear flange will avoid notching the anterior femoral cortex while providing increased surface contact with the trochlear bone, enhancing prosthetic fixation. The only potential adverse effects of increased femoral component flexion would occur in a system that does not allow hyperextension of the femoral/tibial articulation without loss of articular contact or in a posterior-stabilized articulation where there could be post impingement in hyperextension. Total knee systems vary in the amount of hyperextension that can be tolerated.

Obtaining a Medial Release by Removing Peripheral Medial Tibial Bone

Varus deformities can be corrected without performing a formal medial collateral ligament (MCL) release by a so-called reduction tibial osteotomy.^5,6 In mild varus deformity, sufficient medial release can be achieved by removing medial femoral and tibial peripheral osteophytes that tent up the MCL and medial capsule. When this is insufficient, removal of additional peripheral tibial bone further shortens the distance between the origin and insertion of the MCL, effectively lengthening the ligament (Figure 7).

 

An Inverted Cruciform Lateral Retinacular Release to Correct Severe Valgus Deformity

An inverted cruciform lateral retinacular release effectively corrects a severe valgus deformity and avoids the need for a lateral collateral ligament (LCL) release.⁷

The release is best done after bone resection but without trial components in place, because this facilitates exposure to the lateral retinaculum (Figure 8).

The lateral superior genicular vessels should be identified and preserved. The vertical part of the release begins distal to the vessels and ends at the tibial resection. The horizontal limbs extend posteriorly short of the LCL and anteriorly short of the patellar tendon. If the extent of this release does not sufficiently balance the knee, it can be propagated by placing trial components with an insert thickness that stabilizes the medial side. Under this circumstance, the tight lateral side will now prohibit full passive extension. With gentle manipulation of the knee into extension, the lateral release will be propagated to its appropriate length. Postoperative perineal nerve palsies are rare with this technique. Immediate postoperative assessment, however, should always be done and the patient’s dressing loosened and their knee placed in flexion if there is any concern. Almost all of these rare palsies make a complete recovery.

Relieving Posterior Femoral Impingement

Uncapped posterior condylar bone or retained posterior osteophytes can limit both flexion and extension and cause impingement. Trimming the posterior femoral condyles and removing posterior osteophytes is best accomplished using a trial femoral component as a template.⁴ A curved osteotome is passed tangential to the metallic condyles to define the bone requiring resection. After removal of the trial, the outlined bone can be easily and accurately resected.

Minimizing Postoperative Posterior Condylar Bone-Cement Radiolucencies

Zone 4 femoral bone-cement radiolucencies⁸ can be minimized using the “smear” technique.⁴ These radiolucencies are common because most prosthetic femoral components have posterior condyles that are parallel to the femoral fixation lugs and do not allow for compression of this interface during implantation. Most surgeons put no cement on the posterior condylar bone but place it on the inside of the prosthetic condyle instead. The lack of compression upon insertion leads to a poor interface and the resultant lucencies. In the long term, these lucencies could allow access of wear debris to the posterior condylar bone, with the potential for osteolysis and loosening. To improve this interface, cement can be smeared or packed into the posterior condyles and also placed on the posterior condyles of the prosthesis. This could lead to posterior extrusion of some cement during polymerization, so a removable trial insert should be utilized to allow access posteriorly after polymerization is complete.

Predicting Potential Postoperative Flexion

The best indicator of potential postoperative flexion for any individual patient is not preoperative flexion but is intraoperative flexion against gravity measured after capsular closure.⁹ Surgeons should measure and record this value for reference if a patient has difficulty regaining flexion during their recovery (Figure 9).

If a patient had 120° of flexion against gravity after capsular closure but achieves only 80° at 2 months, a knee manipulation is probably indicated. If their flexion after closure was only 80°, a manipulation is unlikely to lead to any improvement.

Summary

The short- and long-term success of TKA is highly dependent on surgical technique that allows proper and safe exposure under all circumstances, correction of deformity, and accurate component implantation while minimizing intraoperative and postoperative complications. The surgical pearls shared above will hopefully aid in achieving these goals.

 

Am J Orthop. 2016;45(6):384-388. Copyright Frontline Medical Communications Inc. 2016. All rights reserved.

After over 4 decades of experience with total knee arthroplasty (TKA), I have learned many lessons regarding surgical technique. These include exposure issues, alignment methods, bone preparation, correction of deformity, and implantation techniques. Most of these lessons have been self-taught, but some have been suggested by or modified from colleague and student interaction. Attribution is given when possible.

The Incision

The skin incision should be marked in flexion rather than extension because the skin moves approximately 1 cm laterally from extension to flexion.¹ This occurs because the tibia internally rotates beneath the skin as the knee is flexed and externally rotates as full extension is achieved. This lateral movement of the skin could bring an incision marked in extension on top of the tibial tubercle when the knee is flexed and may result in pain and dysfunction when the patient attempts to kneel. A review of kneeling ability after TKA showed that most patients are hesitant to kneel initially after their arthroplasty, but gain confidence and improved comfort and ability as their scar matures.²

Exposure

Patellar eversion can be difficult in a markedly obese or ankylosed knee, especially when the patella is difficult to grasp. This is facilitated by the use of a standard patellar clamp that is normally used to compress the patella during component cementation (Figure 1).³

When using this technique, remember to protect the patellar tendon from avulsion by using the techniques described below.

Exposing the Ankylosed Knee and Protecting the Patellar Tendon From Avulsion

A tibial tubercle osteotomy is often recommended in the ankylosed knee but can be avoided by making a short inverted “V” incision in the proximal quadriceps tendon (Figure 2).⁴

This maneuver, along with a smooth 1/8-inchpin in the tibial tubercle, also protects the patellar tendon from avulsing (Figure 3).

The patella can be easily everted and access to the lateral parapatellar scar tissue allows a lateral release to be performed from inside out to further mobilize the knee and enhance exposure. The inverted “V” incision can be closed anatomically, and no modifications of the postoperative physical therapy program are necessary.

Protecting the Soft Tissues During Surgery

Moist wound towels sewn into the joint capsule protect the underlying soft tissues from debris and desiccation during the procedure and will intuitively lower the chance of wound infection from contamination and tissue injury (Figures 4A, 4B).

Since I have done this routinely in both hip and knee arthroplasty over the last 7000 consecutive primary arthroplasties, I have had no operative deep infections. This experience is without the use of antibiotics in the bone cement.

Locating and Coagulating the Lateral Inferior Genicular Vessels

The lateral inferior genicular artery and vein can be easily located and coagulated just outside the posterior rim of the lateral meniscus near the popliteus hiatus. This will minimize both intraoperative and postoperative blood loss.

Determining the Entry Point in the Distal Femur for Intramedullary Alignment Devices

Templating the femoral entry point for insertion of an intramedullary alignment device on a preoperative radiograph will help avoid inadvertent excessive distal femoral valgus resection. This is especially important in valgus knees that have a valgus metaphyseal bow (Figure 5).

In these cases, the entry point must be moved medially and/or the valgus angle chosen must be diminished.

Avoiding Notching of the Anterior Femoral Cortex

Notching the anterior femoral cortex when in-between femoral sizes or when there is a preexisting dysplastic or shallow trochlea (Figure 6)

can be avoided by making the distal femoral resection in an extra 3° of flexion. In most TKA systems, the prosthetic trochlear flange diverges 3° or 4° away from the posterior femoral condyles. If the distal femoral resection is made in an extra 3° of flexion, the femoral component utilized can be anatomically sized off the patient’s posterior femoral condyles and the diverging trochlear flange will avoid notching the anterior femoral cortex while providing increased surface contact with the trochlear bone, enhancing prosthetic fixation. The only potential adverse effects of increased femoral component flexion would occur in a system that does not allow hyperextension of the femoral/tibial articulation without loss of articular contact or in a posterior-stabilized articulation where there could be post impingement in hyperextension. Total knee systems vary in the amount of hyperextension that can be tolerated.

Obtaining a Medial Release by Removing Peripheral Medial Tibial Bone

Varus deformities can be corrected without performing a formal medial collateral ligament (MCL) release by a so-called reduction tibial osteotomy.^5,6 In mild varus deformity, sufficient medial release can be achieved by removing medial femoral and tibial peripheral osteophytes that tent up the MCL and medial capsule. When this is insufficient, removal of additional peripheral tibial bone further shortens the distance between the origin and insertion of the MCL, effectively lengthening the ligament (Figure 7).

 

An Inverted Cruciform Lateral Retinacular Release to Correct Severe Valgus Deformity

An inverted cruciform lateral retinacular release effectively corrects a severe valgus deformity and avoids the need for a lateral collateral ligament (LCL) release.⁷

The release is best done after bone resection but without trial components in place, because this facilitates exposure to the lateral retinaculum (Figure 8).

The lateral superior genicular vessels should be identified and preserved. The vertical part of the release begins distal to the vessels and ends at the tibial resection. The horizontal limbs extend posteriorly short of the LCL and anteriorly short of the patellar tendon. If the extent of this release does not sufficiently balance the knee, it can be propagated by placing trial components with an insert thickness that stabilizes the medial side. Under this circumstance, the tight lateral side will now prohibit full passive extension. With gentle manipulation of the knee into extension, the lateral release will be propagated to its appropriate length. Postoperative perineal nerve palsies are rare with this technique. Immediate postoperative assessment, however, should always be done and the patient’s dressing loosened and their knee placed in flexion if there is any concern. Almost all of these rare palsies make a complete recovery.

Relieving Posterior Femoral Impingement

Uncapped posterior condylar bone or retained posterior osteophytes can limit both flexion and extension and cause impingement. Trimming the posterior femoral condyles and removing posterior osteophytes is best accomplished using a trial femoral component as a template.⁴ A curved osteotome is passed tangential to the metallic condyles to define the bone requiring resection. After removal of the trial, the outlined bone can be easily and accurately resected.

Minimizing Postoperative Posterior Condylar Bone-Cement Radiolucencies

Zone 4 femoral bone-cement radiolucencies⁸ can be minimized using the “smear” technique.⁴ These radiolucencies are common because most prosthetic femoral components have posterior condyles that are parallel to the femoral fixation lugs and do not allow for compression of this interface during implantation. Most surgeons put no cement on the posterior condylar bone but place it on the inside of the prosthetic condyle instead. The lack of compression upon insertion leads to a poor interface and the resultant lucencies. In the long term, these lucencies could allow access of wear debris to the posterior condylar bone, with the potential for osteolysis and loosening. To improve this interface, cement can be smeared or packed into the posterior condyles and also placed on the posterior condyles of the prosthesis. This could lead to posterior extrusion of some cement during polymerization, so a removable trial insert should be utilized to allow access posteriorly after polymerization is complete.

Predicting Potential Postoperative Flexion

The best indicator of potential postoperative flexion for any individual patient is not preoperative flexion but is intraoperative flexion against gravity measured after capsular closure.⁹ Surgeons should measure and record this value for reference if a patient has difficulty regaining flexion during their recovery (Figure 9).

If a patient had 120° of flexion against gravity after capsular closure but achieves only 80° at 2 months, a knee manipulation is probably indicated. If their flexion after closure was only 80°, a manipulation is unlikely to lead to any improvement.

Summary

The short- and long-term success of TKA is highly dependent on surgical technique that allows proper and safe exposure under all circumstances, correction of deformity, and accurate component implantation while minimizing intraoperative and postoperative complications. The surgical pearls shared above will hopefully aid in achieving these goals.

 

Am J Orthop. 2016;45(6):384-388. Copyright Frontline Medical Communications Inc. 2016. All rights reserved.

After over 4 decades of experience with total knee arthroplasty (TKA), I have learned many lessons regarding surgical technique. These include exposure issues, alignment methods, bone preparation, correction of deformity, and implantation techniques. Most of these lessons have been self-taught, but some have been suggested by or modified from colleague and student interaction. Attribution is given when possible.

The Incision

The skin incision should be marked in flexion rather than extension because the skin moves approximately 1 cm laterally from extension to flexion.¹ This occurs because the tibia internally rotates beneath the skin as the knee is flexed and externally rotates as full extension is achieved. This lateral movement of the skin could bring an incision marked in extension on top of the tibial tubercle when the knee is flexed and may result in pain and dysfunction when the patient attempts to kneel. A review of kneeling ability after TKA showed that most patients are hesitant to kneel initially after their arthroplasty, but gain confidence and improved comfort and ability as their scar matures.²

Exposure

Patellar eversion can be difficult in a markedly obese or ankylosed knee, especially when the patella is difficult to grasp. This is facilitated by the use of a standard patellar clamp that is normally used to compress the patella during component cementation (Figure 1).³

When using this technique, remember to protect the patellar tendon from avulsion by using the techniques described below.

Exposing the Ankylosed Knee and Protecting the Patellar Tendon From Avulsion

A tibial tubercle osteotomy is often recommended in the ankylosed knee but can be avoided by making a short inverted “V” incision in the proximal quadriceps tendon (Figure 2).⁴

This maneuver, along with a smooth 1/8-inchpin in the tibial tubercle, also protects the patellar tendon from avulsing (Figure 3).

The patella can be easily everted and access to the lateral parapatellar scar tissue allows a lateral release to be performed from inside out to further mobilize the knee and enhance exposure. The inverted “V” incision can be closed anatomically, and no modifications of the postoperative physical therapy program are necessary.

Protecting the Soft Tissues During Surgery

Moist wound towels sewn into the joint capsule protect the underlying soft tissues from debris and desiccation during the procedure and will intuitively lower the chance of wound infection from contamination and tissue injury (Figures 4A, 4B).

Since I have done this routinely in both hip and knee arthroplasty over the last 7000 consecutive primary arthroplasties, I have had no operative deep infections. This experience is without the use of antibiotics in the bone cement.

Locating and Coagulating the Lateral Inferior Genicular Vessels

The lateral inferior genicular artery and vein can be easily located and coagulated just outside the posterior rim of the lateral meniscus near the popliteus hiatus. This will minimize both intraoperative and postoperative blood loss.

Determining the Entry Point in the Distal Femur for Intramedullary Alignment Devices

Templating the femoral entry point for insertion of an intramedullary alignment device on a preoperative radiograph will help avoid inadvertent excessive distal femoral valgus resection. This is especially important in valgus knees that have a valgus metaphyseal bow (Figure 5).

In these cases, the entry point must be moved medially and/or the valgus angle chosen must be diminished.

Avoiding Notching of the Anterior Femoral Cortex

Notching the anterior femoral cortex when in-between femoral sizes or when there is a preexisting dysplastic or shallow trochlea (Figure 6)

can be avoided by making the distal femoral resection in an extra 3° of flexion. In most TKA systems, the prosthetic trochlear flange diverges 3° or 4° away from the posterior femoral condyles. If the distal femoral resection is made in an extra 3° of flexion, the femoral component utilized can be anatomically sized off the patient’s posterior femoral condyles and the diverging trochlear flange will avoid notching the anterior femoral cortex while providing increased surface contact with the trochlear bone, enhancing prosthetic fixation. The only potential adverse effects of increased femoral component flexion would occur in a system that does not allow hyperextension of the femoral/tibial articulation without loss of articular contact or in a posterior-stabilized articulation where there could be post impingement in hyperextension. Total knee systems vary in the amount of hyperextension that can be tolerated.

Obtaining a Medial Release by Removing Peripheral Medial Tibial Bone

Varus deformities can be corrected without performing a formal medial collateral ligament (MCL) release by a so-called reduction tibial osteotomy.^5,6 In mild varus deformity, sufficient medial release can be achieved by removing medial femoral and tibial peripheral osteophytes that tent up the MCL and medial capsule. When this is insufficient, removal of additional peripheral tibial bone further shortens the distance between the origin and insertion of the MCL, effectively lengthening the ligament (Figure 7).

 

An Inverted Cruciform Lateral Retinacular Release to Correct Severe Valgus Deformity

An inverted cruciform lateral retinacular release effectively corrects a severe valgus deformity and avoids the need for a lateral collateral ligament (LCL) release.⁷

The release is best done after bone resection but without trial components in place, because this facilitates exposure to the lateral retinaculum (Figure 8).

The lateral superior genicular vessels should be identified and preserved. The vertical part of the release begins distal to the vessels and ends at the tibial resection. The horizontal limbs extend posteriorly short of the LCL and anteriorly short of the patellar tendon. If the extent of this release does not sufficiently balance the knee, it can be propagated by placing trial components with an insert thickness that stabilizes the medial side. Under this circumstance, the tight lateral side will now prohibit full passive extension. With gentle manipulation of the knee into extension, the lateral release will be propagated to its appropriate length. Postoperative perineal nerve palsies are rare with this technique. Immediate postoperative assessment, however, should always be done and the patient’s dressing loosened and their knee placed in flexion if there is any concern. Almost all of these rare palsies make a complete recovery.

Relieving Posterior Femoral Impingement

Uncapped posterior condylar bone or retained posterior osteophytes can limit both flexion and extension and cause impingement. Trimming the posterior femoral condyles and removing posterior osteophytes is best accomplished using a trial femoral component as a template.⁴ A curved osteotome is passed tangential to the metallic condyles to define the bone requiring resection. After removal of the trial, the outlined bone can be easily and accurately resected.

Minimizing Postoperative Posterior Condylar Bone-Cement Radiolucencies

Zone 4 femoral bone-cement radiolucencies⁸ can be minimized using the “smear” technique.⁴ These radiolucencies are common because most prosthetic femoral components have posterior condyles that are parallel to the femoral fixation lugs and do not allow for compression of this interface during implantation. Most surgeons put no cement on the posterior condylar bone but place it on the inside of the prosthetic condyle instead. The lack of compression upon insertion leads to a poor interface and the resultant lucencies. In the long term, these lucencies could allow access of wear debris to the posterior condylar bone, with the potential for osteolysis and loosening. To improve this interface, cement can be smeared or packed into the posterior condyles and also placed on the posterior condyles of the prosthesis. This could lead to posterior extrusion of some cement during polymerization, so a removable trial insert should be utilized to allow access posteriorly after polymerization is complete.

Predicting Potential Postoperative Flexion

The best indicator of potential postoperative flexion for any individual patient is not preoperative flexion but is intraoperative flexion against gravity measured after capsular closure.⁹ Surgeons should measure and record this value for reference if a patient has difficulty regaining flexion during their recovery (Figure 9).

If a patient had 120° of flexion against gravity after capsular closure but achieves only 80° at 2 months, a knee manipulation is probably indicated. If their flexion after closure was only 80°, a manipulation is unlikely to lead to any improvement.

Summary

The short- and long-term success of TKA is highly dependent on surgical technique that allows proper and safe exposure under all circumstances, correction of deformity, and accurate component implantation while minimizing intraoperative and postoperative complications. The surgical pearls shared above will hopefully aid in achieving these goals.

 

Am J Orthop. 2016;45(6):384-388. Copyright Frontline Medical Communications Inc. 2016. All rights reserved.

Researchers have discovered a pair of tissue biomarkers that directly contribute to the joint degeneration associated with spine osteoarthritis, according to a study published in the Journal of Clinical Investigation Insight.

The study evaluated tissue biopsies from 55 patients undergoing decompression or discectomy. Investigators screened 2,100 microRNAs and found that microRNA-181a-5p and microRNA-4454 biomarkers are involved in destroying cartilage and increase inflammation, and that measuring these two biomarkers can help clinicians determine the stage to which spine osteoarthritis has progressed, and provide a tool for determining the degree of cartilage destruction.

Researchers have discovered a pair of tissue biomarkers that directly contribute to the joint degeneration associated with spine osteoarthritis, according to a study published in the Journal of Clinical Investigation Insight.

The study evaluated tissue biopsies from 55 patients undergoing decompression or discectomy. Investigators screened 2,100 microRNAs and found that microRNA-181a-5p and microRNA-4454 biomarkers are involved in destroying cartilage and increase inflammation, and that measuring these two biomarkers can help clinicians determine the stage to which spine osteoarthritis has progressed, and provide a tool for determining the degree of cartilage destruction.

Researchers have discovered a pair of tissue biomarkers that directly contribute to the joint degeneration associated with spine osteoarthritis, according to a study published in the Journal of Clinical Investigation Insight.

The study evaluated tissue biopsies from 55 patients undergoing decompression or discectomy. Investigators screened 2,100 microRNAs and found that microRNA-181a-5p and microRNA-4454 biomarkers are involved in destroying cartilage and increase inflammation, and that measuring these two biomarkers can help clinicians determine the stage to which spine osteoarthritis has progressed, and provide a tool for determining the degree of cartilage destruction.

Although rare, periprosthetic fractures remain a significant complication after total knee arthroplasty (TKA), occurring in 0.3% to 2.5% of cases.^1-4 Hirsh and colleagues⁵ were among the first to suggest that anterior femoral notching during TKA was a potential risk factor for postoperative periprosthetic femoral fracture because notching may weaken the anterior femoral cortex. Anterior femoral notching, a cortex violation occurring during an anterior bone cut, occurs in up to 30% of cases.⁶ Using a theoretical biomechanical model, Culp and colleagues¹ found that increasing the depth of the notch defect into the cortex led to reduced torsional strength. In more recent, cadaveric biomechanical studies, notching of the anterior femoral cortex decreased torsional strength by up to 39%.^7,8 Contrary to these biomechanical studies, a retrospective study evaluating 1089 TKAs using 2 implant designs (Anatomic Graduated Component, Biomet and Legacy, Zimmer) demonstrated no significant effect of anterior femoral notching with respect to incidence of supracondylar femur fractures.⁶ That study, however, did not address whether implant design is associated with a differential risk for fracture in the presence of anterior notching.

Previous biomechanical studies have primarily investigated cruciate-retaining (CR) femoral components and properties with respect to anterior notching, even though the posterior-stabilized (PS) design is used more often in the United States.^1,7 According to a Mayo Clinic survey, TKAs with a PS design increased from <10% in 1990 to almost 75% by 1997.⁹ Today, there is little to no consensus about which implant is better, and use of one or the other depends largely on the surgeon and varies widely between countries and regions.¹⁰ PS designs require more bone resection and demonstrate prosthesis-controlled rollback during flexion, whereas CR designs preserve more bone and achieve posterior stabilization via the posterior cruciate ligament.¹¹ Despite these differences in design and mechanics, a 2013 Cochrane review of TKA design found no clinically significant differences between CR and PS with respect to pain, range of motion, or clinical and radiologic outcomes.¹⁰ The reviewers did not specifically address periprosthetic fractures associated with either femoral notching or TKA design, as they could not quantitatively analyze postoperative complications because of the diversity of reports. Given the limited number of reported cases, a review of radiographic findings pertaining to the characteristics of supracondylar fractures in anterior femoral notching was unsuccessful.¹² As the previous biomechanical studies of anterior notching used primarily CR models or no prostheses at all, a study of biomechanical differences between CR and PS designs in the presence of anterior notching is warranted.^1,7,8 Therefore, we conducted a study to assess the effect of anterior femoral notching on torsional strength and load to failure in CR and PS femoral components.

Materials and Methods

Twelve fourth-generation composite adult left femur synthetic sawbones (Sawbones; Pacific Research Laboratories) were selected for their consistent biomechanical properties, vs those of cadaveric specimens; in addition, low intersample variability made them preferable to cadaveric bones given the small sample used in this study.^13,14 All bones were from the same lot. All were visually inspected for defects and found to be acceptable. In each sample, an anterior cortical defect was created by making an anterior cut with an undersized (size 4) posterior referencing guide. In addition, the distance from the proximal end of the notch to the implant fell within 15 mm, as that is the maximum distance from the implant a notch can be placed using a standard femoral cutting jig.¹⁵ Six femora were instrumented with CR implants and 6 with PS implants (DePuy Synthes). Implants were placed using standardized cuts. Before testing, each implant was inspected for proper fit and found to be securely fastened to the femur. In addition, precision calipers were used to measure notch depth and distance from notch to implant before loading. A custom polymethylmethacrylate torsion jig was used to fix each instrumented femur proximally and distally on the femoral implant (Figure 1). Care was taken to ensure the distal jig engaged only the implant, thus isolating the notch as a stress riser. Each femur was loaded in external rotation through the proximal femoral jig along the anatomical axis. Use of external rotation was based on study findings implicating external rotation of the tibia as the most likely mechanism for generating a fracture in the event of a fall.¹² Furthermore, distal femur fractures are predominantly spiral as opposed to butterfly or bending—an indication that torsion is the most likely mechanism of failure.¹⁶ With no axial rotation possible within the prosthesis, increased torsional stress is undoubtedly generated within adjacent bone. Each specimen underwent torsional stiffness testing and then load to failure. Torsional stiffness was measured by slowly loading each femur in external rotation, from 1 to 18 Nm for 3 cycles at a displacement rate of 0.5° per second. Each specimen then underwent torsional load-to-failure testing on an Instron 5800R machine at a rate of 0.5° per second. Failure was defined as the moment of fracture and subsequent decrease in torsional load—determined graphically by the peak torsional load followed immediately by a sharp decrease in load. Stiffness was determined as the slope of torque to the displacement curve for each cycle, and torque to failure was the highest recorded torque before fracture. Fracture pattern was noted after failure. A sample size of 6 specimens per group provided 80% power to detect a between-group difference of 1 Nm per degree in stiffness, using an estimated SD of 0.7 Nm per degree. In our statistical analysis, continuous variables are reported as means and SDs. Data from our torsional stiffness and load-to-failure testing were analyzed with unpaired 2-sample t tests, and P < .05 was considered statistically significant.

 

 

Results

We did not detect a statistical difference in notch depth, notch-to-implant distance, or femoral length between the CR and PS groups. Mean (SD) notch depth was 6.0 (1.3) mm for CR and 4.9 (1.0) mm for PS (P = .13); mean (SD) distance from the proximal end of the notch to the implant was 13.8 (1.7) mm for CR and 11.1 (3.2) mm for PS (P = .08); and mean (SD) femoral length was 46.2 (0.1) cm for CR and 46.2 (0.1) cm for PS (P = .60).

Mean (SD) torsional stiffness for the first 3 precycles was 6.2 (1.2), 8.7 (1.5), and 8.8 (1.4) Nm per degree for the CR group and 6.0 (0.7), 8.4 (1.4), and 8.6 (1.4) Nm per degree for the PS group; the differences were not statistically significant (Figure 2A). In addition, there were no statistically significant differences in mean (SD) stiffness at failure between CR, 6.5 (0.7) Nm per degree, and PS, 7.1 (0.9) Nm per degree (P = .24; Figure 2B) or in mean (SD) final torque at failure between CR, 62.4 (9.4) Nm, and PS, 62.7 (12.2) Nm (P = .95; Figure 2C).

All fractures in both groups were oblique fractures originating at the proximal angle of the notch and extended proximally. None extended distally into the box. Fracture locations and patterns were identical in the CR and PS groups of femurs (Figure 3).

Discussion

Periprosthetic fractures after TKA remain rare. However, these fractures can significantly increase morbidity and complications. Anterior femoral notching occurs inadvertently in 30% to 40% of TKAs.^6,17 The impact of femoral notching on supracondylar femur fracture is inconsistent between biomechanical and retrospective clinical studies. Retrospective studies failed to find a significant correlation between anterior femoral notching and supracondylar femur fractures.^6,17 However, findings of biomechanical studies have suggested that a notch 3 mm deep will reduce the torsional strength of the femur by 29%.⁷ Another study, using 3-dimensional finite element analysis, showed a significant increase in local stress with a notch deeper than 3 mm.¹⁵

To our knowledge, no clinical studies, including the aforementioned Cochrane review,¹⁰ have specifically evaluated the difference in risk for periprosthetic fracture between different TKA models in the presence of notching.¹¹ The biomechanical differences between implant designs could be a confounding factor in the results of past studies. More bone resection is required in PS designs than in CR designs. The position of the PS intercondylar cutout, much lower than the top of the patella flange, should not increase susceptibility to fractures more than in CR designs, but this hypothesis, though accepted, has not been validated biomechanically or addressed specifically in prospective or retrospective clinical analysis. In the present study, we used a biomechanical model to replicate an external rotation failure mechanism and quantify the differences in torsional strength and load to failure between CR TKA and PS TKA models in the presence of anterior femoral notching. Our results showed no significant differences in torsional stiffness, stiffness at failure, or torque at failure between the CR and PS design groups in the presence of anterior femoral notching.

In this study, all femoral fractures were oblique, and they all originated at the site of the cortical defect, not the notch—a situation markedly different from having bending forces applied to the femur. Previous biomechanical data indicated that bending forces applied to a notched femur cause fractures originating at the notch, whereas torsional forces applied to a notched femur cause fractures originating at the anterior aspect of the bone–component interface.⁷ The difference is attributable to study design. Our femurs were held fixed at their proximal end, which may have exacerbated any bending forces applied during external rotation, but we thought constraining the proximal femur would better replicate a fall involving external rotation.

 

 

More important for our study, an oblique fracture pattern was noted for both design groups (CR and PS), indicating the fracture pattern was unrelated to the area from which bone was resected for the PS design. All femur fractures in both design groups occurred proximal to a well-fixed prosthesis, indicating they should be classified as Vancouver C fractures. This is significant because intercondylar fossa resection (PS group) did not convert the fractures into Vancouver B2 fractures, which involve prosthesis loosening caused by pericomponent fracture.¹⁸ This simple observation validated our hypothesis that there would be no biomechanical differences between CR and PS designs with respect to the effects of anterior femoral notching. This lack of a significant difference may be attributed to the PS intercondylar cutout being much lower than the top of the anterior flange shielding the resected bone deep to the anterior flange.⁷ In addition, given the rarity of supracondylar fractures and the lack of sufficient relevant clinical data, it is difficult to speculate on the fracture patterns observed in clinical cases versus biomechanical studies.¹²

The use of synthetic bone models instead of cadaveric specimens could be seen as a limitation. Although synthetic bones may not reproduce the mechanism of failure in living and cadaveric femurs, the mechanical properties of synthetic bones have previously been found to fall within the range of those of cadaveric bones under axial loading, bending, and torsion testing.^13,14 As a uniform testing material, synthetic bones allow removal of the confounding variations in bone size and quality that plague biomechanical studies in cadaveric bones.^13,14 Interfemoral variability was 20 to 200 times higher in cadaveric femurs than in synthetic bones, which makes synthetic femurs preferable to cadaveric femurs, especially in studies with a small sample size.^13,14 In addition, a uniform specimen provides consistent, reproducible osteotomies, which were crucial for consistent mechanical evaluation of each configuration in this study.

The long-term clinical significance of anterior femoral notching in periprosthetic fractures is equivocal, possibly because most studies predominantly use CR implants.⁶ This may not be an issue if it is shown that CR and PS implants have the same mechanical properties. Despite the differences between clinical studies and our biomechanical study, reevaluation of clinical data is not warranted given the biomechanical data we present here. Results of biomechanical studies like ours still suggest an increased immediate postoperative risk for supracondylar fracture after anterior cortical notching of the femur.^5,7 Ultimately, this study found that, compared with a CR design, a PS design did not alter the torsional biomechanical properties or fracture pattern of an anteriorly notched femur.

Although rare, periprosthetic fractures remain a significant complication after total knee arthroplasty (TKA), occurring in 0.3% to 2.5% of cases.^1-4 Hirsh and colleagues⁵ were among the first to suggest that anterior femoral notching during TKA was a potential risk factor for postoperative periprosthetic femoral fracture because notching may weaken the anterior femoral cortex. Anterior femoral notching, a cortex violation occurring during an anterior bone cut, occurs in up to 30% of cases.⁶ Using a theoretical biomechanical model, Culp and colleagues¹ found that increasing the depth of the notch defect into the cortex led to reduced torsional strength. In more recent, cadaveric biomechanical studies, notching of the anterior femoral cortex decreased torsional strength by up to 39%.^7,8 Contrary to these biomechanical studies, a retrospective study evaluating 1089 TKAs using 2 implant designs (Anatomic Graduated Component, Biomet and Legacy, Zimmer) demonstrated no significant effect of anterior femoral notching with respect to incidence of supracondylar femur fractures.⁶ That study, however, did not address whether implant design is associated with a differential risk for fracture in the presence of anterior notching.

Previous biomechanical studies have primarily investigated cruciate-retaining (CR) femoral components and properties with respect to anterior notching, even though the posterior-stabilized (PS) design is used more often in the United States.^1,7 According to a Mayo Clinic survey, TKAs with a PS design increased from <10% in 1990 to almost 75% by 1997.⁹ Today, there is little to no consensus about which implant is better, and use of one or the other depends largely on the surgeon and varies widely between countries and regions.¹⁰ PS designs require more bone resection and demonstrate prosthesis-controlled rollback during flexion, whereas CR designs preserve more bone and achieve posterior stabilization via the posterior cruciate ligament.¹¹ Despite these differences in design and mechanics, a 2013 Cochrane review of TKA design found no clinically significant differences between CR and PS with respect to pain, range of motion, or clinical and radiologic outcomes.¹⁰ The reviewers did not specifically address periprosthetic fractures associated with either femoral notching or TKA design, as they could not quantitatively analyze postoperative complications because of the diversity of reports. Given the limited number of reported cases, a review of radiographic findings pertaining to the characteristics of supracondylar fractures in anterior femoral notching was unsuccessful.¹² As the previous biomechanical studies of anterior notching used primarily CR models or no prostheses at all, a study of biomechanical differences between CR and PS designs in the presence of anterior notching is warranted.^1,7,8 Therefore, we conducted a study to assess the effect of anterior femoral notching on torsional strength and load to failure in CR and PS femoral components.

Materials and Methods

Twelve fourth-generation composite adult left femur synthetic sawbones (Sawbones; Pacific Research Laboratories) were selected for their consistent biomechanical properties, vs those of cadaveric specimens; in addition, low intersample variability made them preferable to cadaveric bones given the small sample used in this study.^13,14 All bones were from the same lot. All were visually inspected for defects and found to be acceptable. In each sample, an anterior cortical defect was created by making an anterior cut with an undersized (size 4) posterior referencing guide. In addition, the distance from the proximal end of the notch to the implant fell within 15 mm, as that is the maximum distance from the implant a notch can be placed using a standard femoral cutting jig.¹⁵ Six femora were instrumented with CR implants and 6 with PS implants (DePuy Synthes). Implants were placed using standardized cuts. Before testing, each implant was inspected for proper fit and found to be securely fastened to the femur. In addition, precision calipers were used to measure notch depth and distance from notch to implant before loading. A custom polymethylmethacrylate torsion jig was used to fix each instrumented femur proximally and distally on the femoral implant (Figure 1). Care was taken to ensure the distal jig engaged only the implant, thus isolating the notch as a stress riser. Each femur was loaded in external rotation through the proximal femoral jig along the anatomical axis. Use of external rotation was based on study findings implicating external rotation of the tibia as the most likely mechanism for generating a fracture in the event of a fall.¹² Furthermore, distal femur fractures are predominantly spiral as opposed to butterfly or bending—an indication that torsion is the most likely mechanism of failure.¹⁶ With no axial rotation possible within the prosthesis, increased torsional stress is undoubtedly generated within adjacent bone. Each specimen underwent torsional stiffness testing and then load to failure. Torsional stiffness was measured by slowly loading each femur in external rotation, from 1 to 18 Nm for 3 cycles at a displacement rate of 0.5° per second. Each specimen then underwent torsional load-to-failure testing on an Instron 5800R machine at a rate of 0.5° per second. Failure was defined as the moment of fracture and subsequent decrease in torsional load—determined graphically by the peak torsional load followed immediately by a sharp decrease in load. Stiffness was determined as the slope of torque to the displacement curve for each cycle, and torque to failure was the highest recorded torque before fracture. Fracture pattern was noted after failure. A sample size of 6 specimens per group provided 80% power to detect a between-group difference of 1 Nm per degree in stiffness, using an estimated SD of 0.7 Nm per degree. In our statistical analysis, continuous variables are reported as means and SDs. Data from our torsional stiffness and load-to-failure testing were analyzed with unpaired 2-sample t tests, and P < .05 was considered statistically significant.

 

 

Results

We did not detect a statistical difference in notch depth, notch-to-implant distance, or femoral length between the CR and PS groups. Mean (SD) notch depth was 6.0 (1.3) mm for CR and 4.9 (1.0) mm for PS (P = .13); mean (SD) distance from the proximal end of the notch to the implant was 13.8 (1.7) mm for CR and 11.1 (3.2) mm for PS (P = .08); and mean (SD) femoral length was 46.2 (0.1) cm for CR and 46.2 (0.1) cm for PS (P = .60).

Mean (SD) torsional stiffness for the first 3 precycles was 6.2 (1.2), 8.7 (1.5), and 8.8 (1.4) Nm per degree for the CR group and 6.0 (0.7), 8.4 (1.4), and 8.6 (1.4) Nm per degree for the PS group; the differences were not statistically significant (Figure 2A). In addition, there were no statistically significant differences in mean (SD) stiffness at failure between CR, 6.5 (0.7) Nm per degree, and PS, 7.1 (0.9) Nm per degree (P = .24; Figure 2B) or in mean (SD) final torque at failure between CR, 62.4 (9.4) Nm, and PS, 62.7 (12.2) Nm (P = .95; Figure 2C).

All fractures in both groups were oblique fractures originating at the proximal angle of the notch and extended proximally. None extended distally into the box. Fracture locations and patterns were identical in the CR and PS groups of femurs (Figure 3).

Discussion

Periprosthetic fractures after TKA remain rare. However, these fractures can significantly increase morbidity and complications. Anterior femoral notching occurs inadvertently in 30% to 40% of TKAs.^6,17 The impact of femoral notching on supracondylar femur fracture is inconsistent between biomechanical and retrospective clinical studies. Retrospective studies failed to find a significant correlation between anterior femoral notching and supracondylar femur fractures.^6,17 However, findings of biomechanical studies have suggested that a notch 3 mm deep will reduce the torsional strength of the femur by 29%.⁷ Another study, using 3-dimensional finite element analysis, showed a significant increase in local stress with a notch deeper than 3 mm.¹⁵

To our knowledge, no clinical studies, including the aforementioned Cochrane review,¹⁰ have specifically evaluated the difference in risk for periprosthetic fracture between different TKA models in the presence of notching.¹¹ The biomechanical differences between implant designs could be a confounding factor in the results of past studies. More bone resection is required in PS designs than in CR designs. The position of the PS intercondylar cutout, much lower than the top of the patella flange, should not increase susceptibility to fractures more than in CR designs, but this hypothesis, though accepted, has not been validated biomechanically or addressed specifically in prospective or retrospective clinical analysis. In the present study, we used a biomechanical model to replicate an external rotation failure mechanism and quantify the differences in torsional strength and load to failure between CR TKA and PS TKA models in the presence of anterior femoral notching. Our results showed no significant differences in torsional stiffness, stiffness at failure, or torque at failure between the CR and PS design groups in the presence of anterior femoral notching.

In this study, all femoral fractures were oblique, and they all originated at the site of the cortical defect, not the notch—a situation markedly different from having bending forces applied to the femur. Previous biomechanical data indicated that bending forces applied to a notched femur cause fractures originating at the notch, whereas torsional forces applied to a notched femur cause fractures originating at the anterior aspect of the bone–component interface.⁷ The difference is attributable to study design. Our femurs were held fixed at their proximal end, which may have exacerbated any bending forces applied during external rotation, but we thought constraining the proximal femur would better replicate a fall involving external rotation.

 

 

More important for our study, an oblique fracture pattern was noted for both design groups (CR and PS), indicating the fracture pattern was unrelated to the area from which bone was resected for the PS design. All femur fractures in both design groups occurred proximal to a well-fixed prosthesis, indicating they should be classified as Vancouver C fractures. This is significant because intercondylar fossa resection (PS group) did not convert the fractures into Vancouver B2 fractures, which involve prosthesis loosening caused by pericomponent fracture.¹⁸ This simple observation validated our hypothesis that there would be no biomechanical differences between CR and PS designs with respect to the effects of anterior femoral notching. This lack of a significant difference may be attributed to the PS intercondylar cutout being much lower than the top of the anterior flange shielding the resected bone deep to the anterior flange.⁷ In addition, given the rarity of supracondylar fractures and the lack of sufficient relevant clinical data, it is difficult to speculate on the fracture patterns observed in clinical cases versus biomechanical studies.¹²

The use of synthetic bone models instead of cadaveric specimens could be seen as a limitation. Although synthetic bones may not reproduce the mechanism of failure in living and cadaveric femurs, the mechanical properties of synthetic bones have previously been found to fall within the range of those of cadaveric bones under axial loading, bending, and torsion testing.^13,14 As a uniform testing material, synthetic bones allow removal of the confounding variations in bone size and quality that plague biomechanical studies in cadaveric bones.^13,14 Interfemoral variability was 20 to 200 times higher in cadaveric femurs than in synthetic bones, which makes synthetic femurs preferable to cadaveric femurs, especially in studies with a small sample size.^13,14 In addition, a uniform specimen provides consistent, reproducible osteotomies, which were crucial for consistent mechanical evaluation of each configuration in this study.

The long-term clinical significance of anterior femoral notching in periprosthetic fractures is equivocal, possibly because most studies predominantly use CR implants.⁶ This may not be an issue if it is shown that CR and PS implants have the same mechanical properties. Despite the differences between clinical studies and our biomechanical study, reevaluation of clinical data is not warranted given the biomechanical data we present here. Results of biomechanical studies like ours still suggest an increased immediate postoperative risk for supracondylar fracture after anterior cortical notching of the femur.^5,7 Ultimately, this study found that, compared with a CR design, a PS design did not alter the torsional biomechanical properties or fracture pattern of an anteriorly notched femur.

Although rare, periprosthetic fractures remain a significant complication after total knee arthroplasty (TKA), occurring in 0.3% to 2.5% of cases.^1-4 Hirsh and colleagues⁵ were among the first to suggest that anterior femoral notching during TKA was a potential risk factor for postoperative periprosthetic femoral fracture because notching may weaken the anterior femoral cortex. Anterior femoral notching, a cortex violation occurring during an anterior bone cut, occurs in up to 30% of cases.⁶ Using a theoretical biomechanical model, Culp and colleagues¹ found that increasing the depth of the notch defect into the cortex led to reduced torsional strength. In more recent, cadaveric biomechanical studies, notching of the anterior femoral cortex decreased torsional strength by up to 39%.^7,8 Contrary to these biomechanical studies, a retrospective study evaluating 1089 TKAs using 2 implant designs (Anatomic Graduated Component, Biomet and Legacy, Zimmer) demonstrated no significant effect of anterior femoral notching with respect to incidence of supracondylar femur fractures.⁶ That study, however, did not address whether implant design is associated with a differential risk for fracture in the presence of anterior notching.

Previous biomechanical studies have primarily investigated cruciate-retaining (CR) femoral components and properties with respect to anterior notching, even though the posterior-stabilized (PS) design is used more often in the United States.^1,7 According to a Mayo Clinic survey, TKAs with a PS design increased from <10% in 1990 to almost 75% by 1997.⁹ Today, there is little to no consensus about which implant is better, and use of one or the other depends largely on the surgeon and varies widely between countries and regions.¹⁰ PS designs require more bone resection and demonstrate prosthesis-controlled rollback during flexion, whereas CR designs preserve more bone and achieve posterior stabilization via the posterior cruciate ligament.¹¹ Despite these differences in design and mechanics, a 2013 Cochrane review of TKA design found no clinically significant differences between CR and PS with respect to pain, range of motion, or clinical and radiologic outcomes.¹⁰ The reviewers did not specifically address periprosthetic fractures associated with either femoral notching or TKA design, as they could not quantitatively analyze postoperative complications because of the diversity of reports. Given the limited number of reported cases, a review of radiographic findings pertaining to the characteristics of supracondylar fractures in anterior femoral notching was unsuccessful.¹² As the previous biomechanical studies of anterior notching used primarily CR models or no prostheses at all, a study of biomechanical differences between CR and PS designs in the presence of anterior notching is warranted.^1,7,8 Therefore, we conducted a study to assess the effect of anterior femoral notching on torsional strength and load to failure in CR and PS femoral components.

Materials and Methods

Twelve fourth-generation composite adult left femur synthetic sawbones (Sawbones; Pacific Research Laboratories) were selected for their consistent biomechanical properties, vs those of cadaveric specimens; in addition, low intersample variability made them preferable to cadaveric bones given the small sample used in this study.^13,14 All bones were from the same lot. All were visually inspected for defects and found to be acceptable. In each sample, an anterior cortical defect was created by making an anterior cut with an undersized (size 4) posterior referencing guide. In addition, the distance from the proximal end of the notch to the implant fell within 15 mm, as that is the maximum distance from the implant a notch can be placed using a standard femoral cutting jig.¹⁵ Six femora were instrumented with CR implants and 6 with PS implants (DePuy Synthes). Implants were placed using standardized cuts. Before testing, each implant was inspected for proper fit and found to be securely fastened to the femur. In addition, precision calipers were used to measure notch depth and distance from notch to implant before loading. A custom polymethylmethacrylate torsion jig was used to fix each instrumented femur proximally and distally on the femoral implant (Figure 1). Care was taken to ensure the distal jig engaged only the implant, thus isolating the notch as a stress riser. Each femur was loaded in external rotation through the proximal femoral jig along the anatomical axis. Use of external rotation was based on study findings implicating external rotation of the tibia as the most likely mechanism for generating a fracture in the event of a fall.¹² Furthermore, distal femur fractures are predominantly spiral as opposed to butterfly or bending—an indication that torsion is the most likely mechanism of failure.¹⁶ With no axial rotation possible within the prosthesis, increased torsional stress is undoubtedly generated within adjacent bone. Each specimen underwent torsional stiffness testing and then load to failure. Torsional stiffness was measured by slowly loading each femur in external rotation, from 1 to 18 Nm for 3 cycles at a displacement rate of 0.5° per second. Each specimen then underwent torsional load-to-failure testing on an Instron 5800R machine at a rate of 0.5° per second. Failure was defined as the moment of fracture and subsequent decrease in torsional load—determined graphically by the peak torsional load followed immediately by a sharp decrease in load. Stiffness was determined as the slope of torque to the displacement curve for each cycle, and torque to failure was the highest recorded torque before fracture. Fracture pattern was noted after failure. A sample size of 6 specimens per group provided 80% power to detect a between-group difference of 1 Nm per degree in stiffness, using an estimated SD of 0.7 Nm per degree. In our statistical analysis, continuous variables are reported as means and SDs. Data from our torsional stiffness and load-to-failure testing were analyzed with unpaired 2-sample t tests, and P < .05 was considered statistically significant.

 

 

Results

We did not detect a statistical difference in notch depth, notch-to-implant distance, or femoral length between the CR and PS groups. Mean (SD) notch depth was 6.0 (1.3) mm for CR and 4.9 (1.0) mm for PS (P = .13); mean (SD) distance from the proximal end of the notch to the implant was 13.8 (1.7) mm for CR and 11.1 (3.2) mm for PS (P = .08); and mean (SD) femoral length was 46.2 (0.1) cm for CR and 46.2 (0.1) cm for PS (P = .60).

Mean (SD) torsional stiffness for the first 3 precycles was 6.2 (1.2), 8.7 (1.5), and 8.8 (1.4) Nm per degree for the CR group and 6.0 (0.7), 8.4 (1.4), and 8.6 (1.4) Nm per degree for the PS group; the differences were not statistically significant (Figure 2A). In addition, there were no statistically significant differences in mean (SD) stiffness at failure between CR, 6.5 (0.7) Nm per degree, and PS, 7.1 (0.9) Nm per degree (P = .24; Figure 2B) or in mean (SD) final torque at failure between CR, 62.4 (9.4) Nm, and PS, 62.7 (12.2) Nm (P = .95; Figure 2C).

All fractures in both groups were oblique fractures originating at the proximal angle of the notch and extended proximally. None extended distally into the box. Fracture locations and patterns were identical in the CR and PS groups of femurs (Figure 3).

Discussion

Periprosthetic fractures after TKA remain rare. However, these fractures can significantly increase morbidity and complications. Anterior femoral notching occurs inadvertently in 30% to 40% of TKAs.^6,17 The impact of femoral notching on supracondylar femur fracture is inconsistent between biomechanical and retrospective clinical studies. Retrospective studies failed to find a significant correlation between anterior femoral notching and supracondylar femur fractures.^6,17 However, findings of biomechanical studies have suggested that a notch 3 mm deep will reduce the torsional strength of the femur by 29%.⁷ Another study, using 3-dimensional finite element analysis, showed a significant increase in local stress with a notch deeper than 3 mm.¹⁵

To our knowledge, no clinical studies, including the aforementioned Cochrane review,¹⁰ have specifically evaluated the difference in risk for periprosthetic fracture between different TKA models in the presence of notching.¹¹ The biomechanical differences between implant designs could be a confounding factor in the results of past studies. More bone resection is required in PS designs than in CR designs. The position of the PS intercondylar cutout, much lower than the top of the patella flange, should not increase susceptibility to fractures more than in CR designs, but this hypothesis, though accepted, has not been validated biomechanically or addressed specifically in prospective or retrospective clinical analysis. In the present study, we used a biomechanical model to replicate an external rotation failure mechanism and quantify the differences in torsional strength and load to failure between CR TKA and PS TKA models in the presence of anterior femoral notching. Our results showed no significant differences in torsional stiffness, stiffness at failure, or torque at failure between the CR and PS design groups in the presence of anterior femoral notching.

In this study, all femoral fractures were oblique, and they all originated at the site of the cortical defect, not the notch—a situation markedly different from having bending forces applied to the femur. Previous biomechanical data indicated that bending forces applied to a notched femur cause fractures originating at the notch, whereas torsional forces applied to a notched femur cause fractures originating at the anterior aspect of the bone–component interface.⁷ The difference is attributable to study design. Our femurs were held fixed at their proximal end, which may have exacerbated any bending forces applied during external rotation, but we thought constraining the proximal femur would better replicate a fall involving external rotation.

 

 

More important for our study, an oblique fracture pattern was noted for both design groups (CR and PS), indicating the fracture pattern was unrelated to the area from which bone was resected for the PS design. All femur fractures in both design groups occurred proximal to a well-fixed prosthesis, indicating they should be classified as Vancouver C fractures. This is significant because intercondylar fossa resection (PS group) did not convert the fractures into Vancouver B2 fractures, which involve prosthesis loosening caused by pericomponent fracture.¹⁸ This simple observation validated our hypothesis that there would be no biomechanical differences between CR and PS designs with respect to the effects of anterior femoral notching. This lack of a significant difference may be attributed to the PS intercondylar cutout being much lower than the top of the anterior flange shielding the resected bone deep to the anterior flange.⁷ In addition, given the rarity of supracondylar fractures and the lack of sufficient relevant clinical data, it is difficult to speculate on the fracture patterns observed in clinical cases versus biomechanical studies.¹²

The use of synthetic bone models instead of cadaveric specimens could be seen as a limitation. Although synthetic bones may not reproduce the mechanism of failure in living and cadaveric femurs, the mechanical properties of synthetic bones have previously been found to fall within the range of those of cadaveric bones under axial loading, bending, and torsion testing.^13,14 As a uniform testing material, synthetic bones allow removal of the confounding variations in bone size and quality that plague biomechanical studies in cadaveric bones.^13,14 Interfemoral variability was 20 to 200 times higher in cadaveric femurs than in synthetic bones, which makes synthetic femurs preferable to cadaveric femurs, especially in studies with a small sample size.^13,14 In addition, a uniform specimen provides consistent, reproducible osteotomies, which were crucial for consistent mechanical evaluation of each configuration in this study.

The long-term clinical significance of anterior femoral notching in periprosthetic fractures is equivocal, possibly because most studies predominantly use CR implants.⁶ This may not be an issue if it is shown that CR and PS implants have the same mechanical properties. Despite the differences between clinical studies and our biomechanical study, reevaluation of clinical data is not warranted given the biomechanical data we present here. Results of biomechanical studies like ours still suggest an increased immediate postoperative risk for supracondylar fracture after anterior cortical notching of the femur.^5,7 Ultimately, this study found that, compared with a CR design, a PS design did not alter the torsional biomechanical properties or fracture pattern of an anteriorly notched femur.

During total knee arthroplasty (TKA), traditionally a thigh tourniquet is used to minimize blood loss. Although intraoperative blood loss is negligible, postoperative blood loss can be extensive, and patients often require blood transfusions. Transfusions expose patients to clinical risks and increase costs. Well-documented transfusion complications include allergic reaction, transfusion-related acute lung injury, transfusion-associated circulatory overload, venous thromboembolism, graft vs host disease, bloodborne infections, and immunomodulation.¹ Although measures are taken to reduce these risks, the costs associated with transfusions continue to escalate.²

Postoperative bleeding is attributed to fibrinolytic system activation. The antifibrinolytic agent aminocaproic acid (ACA), a synthetic analogue of the amino acid lysine, acts by competitively blocking the lysine-binding site of plasminogen, inhibiting fibrinolysis.³ Multiple studies have shown that ACA and a similar drug, tranexamic acid, can reduce postoperative blood loss when used intravenously in unilateral TKA.^4,5 However, more studies are needed to evaluate antifibrinolytic agents with comparative controls using standardized procedures and documented outcome measures. In addition, the majority of studies have used tranexamic acid rather than ACA, despite the lower cost and similar efficacy of ACA.^1,4 ACA is an inexpensive medication with a low risk profile, making it an attractive alternative to historical post-TKA management (which has a higher rate of blood transfusions) and a viable replacement in protocols already implementing tranexamic acid, the more expensive antifibrinolytic.^5,6 It has been proposed that ACA use reduces equipment (drain) costs, blood transfusion costs, exposure to complications of blood loss, and transfusion reactions and reduces or eliminates the need for costly medications, such as erythropoiesis-stimulating agents.

Kagoma and colleagues⁵ reported that antifibrinolytic agents may reduce bleeding by at least 300 mL and may reduce the need for transfusions by 50% or eliminate this need altogether. Other antifibrinolytic agents have been studied in unilateral TKA, with results showing decreased drainage and improved postoperative hemoglobin (Hb) levels.⁶

We conducted a study to evaluate the effectiveness of a single intraoperative dose of ACA in reducing postoperative blood loss and the need for blood transfusions with increased preservation of postoperative Hb levels.

Methods

In October 2011, Dr. Anderson initiated an intraoperative intravenous (IV) ACA protocol for primary unilateral TKA. Given the decreased drain output immediately observed, and patients’ increased postoperative Hb levels, a retrospective study was proposed. After obtaining full Institutional Review Board approval for the study, we retrospectively reviewed the medical charts of 50 consecutive patients who underwent primary unilateral TKA—the last 25 who had the surgery before the IV ACA protocol was initiated (control group) and the first 25 who were given the IV ACA medication during the surgery (antifibrinolytic group). Inclusion criteria were primary unilateral TKA, no bleeding dyscrasia, no history of anaphylactic response to antifibrinolytic agents, no history of deep vein thrombosis, and normal preoperative coagulation parameters, international normalized ratio (INR), and partial thromboplastin time. Exclusion criteria included lateral corner release, lateral retinacular release, combined extensive deep and superficial medial collateral ligament releases, and cardiac or peripheral stent in place.

Each surgery—a standard primary unilateral TKA with an intramedullary femoral component and an extramedullary tibial component—was performed by Dr. Anderson. Each component was cemented. Each patient underwent a posterior cruciate ligament release and/or a deep medial collateral ligament release. A well-padded thigh tourniquet was inflated before surgical incision, and it remained inflated until all postoperative surgical dressings were applied. Each patient in the antifibrinolytic group was given a 10-g dose of IV ACA at the start of implant cementation; the dose was administered over 10 minutes and was completely infused before tourniquet deflation. For each patient in the control group, a suction drain (Constavac, Stryker) was used. As postoperative drainage was so insignificant in the first 12 antifibrinolytic cases, use of the drain was then discontinued.

 

 

All patients received standard postoperative deep vein thrombosis prophylaxis in the form of warfarin in accordance with existing practice. Warfarin was given once a day starting the night of surgery and was continued until discharge based on daily INR values with an agreed-on target of 2.0. Thigh-high compression stockings and calf sequential compression devices were used in all cases. No patient in either group predonated blood or was given erythropoietin injections before or after surgery. Postoperative allogeneic transfusions were given to patients who were clinically symptomatic or short of breath; patients with hypotension uncorrectable with IV volume supplementation and an Hb level under 9.0 g/dL; and patients with an Hb level under 7.0 g/dL regardless of symptoms. All patients were monitored for postoperative adverse events and complications.

Postoperative blood loss (drain output), Hb levels on postoperative days 1 and 2 (POD-1, POD-2), blood transfusion amounts, and complications were recorded for all patients. Group means were compared with 2-sample t tests for independent samples. Data are reported as group means and SDs. All significance tests were 2-tailed, and statistical significance was set at P < .05.

Results

Fifty patients enrolled in the study: 25 in the control group and 25 in the antifibrinolytic group. Table 1 compares the main characteristics of the 2 groups. No significant differences were found between these groups for any of the characteristics considered.

There was significantly (P < .0001) more postoperative drainage in the control group: Mean drain output was 410.9 mL for the control group and 155.0 mL for the antifibrinolytic group (Table 2). Patients in the antifibrinolytic group did not receive any blood transfusions, whereas 40% of patients in the control group received transfusions (P = .022). On average, the transfused patients received 0.4 unit of packed red blood cells.

Although there was no statistically significant difference in POD-1 or POD-2 Hb levels between the antifibrinolytic and control groups, the antifibrinolytic group trended higher on POD-1 (11.1 g vs 10.7 g; P = .108) and POD-2 (11.5 g vs 10.2 g; P = .117) (Table 3). Mean Hb level was 8.1 g for control patients transfused on POD-1 and 7.9 g for control patients transfused on POD-2. For control patients who were not transfused, mean Hb level was 10.7 g on POD-1 and 10.2 g on POD-2.

There were no adverse events (eg, anaphylaxis, hypersensitivity) in either group, and there was no difference in incision drainage or returns to operating room between the groups.

Discussion

In TKA, a tourniquet is used to minimize intraoperative blood loss; postoperative bleeding, however, is often extensive. Both surgery and tourniquet use are reported to enhance local fibrinolytic activity within the limb.⁸ The synthetic antifibrinolytic ACA reduces blood loss by clot stabilization rather than by promotion of clot formation.⁸

In the present study, a single intraoperative dose of IV ACA administered in primary unilateral TKA significantly reduced postoperative wound drainage and eliminated the need for postoperative allogeneic blood transfusions. In addition, patients who received ACA had higher Hb levels on POD-1 and POD-2. These results are similar to those of other clinical trials in which external blood losses were measured.^4-7 The postoperative drain output differences (~250 mL) in our study are clinically relevant, as they indicate significant reductions in postoperative blood loss with the implementation of an antifibrinolytic operative protocol.

In a study by Ponnusamy and colleagues,¹ blood transfusion after orthopedic surgery accounted for 10% of all packed red blood cell transfusions, but use varied widely. National TKA transfusion rates vary from 4.3% to 63.8% among surgeons and hospitals.⁹ This evidence calls for standardization and critical review of practices to ensure more efficient use of blood products, effectively protecting patients from unneeded complications and reducing hospital costs. Mounting evidence supporting the efficacy of ACA in reducing perioperative blood loss and lowering postoperative blood transfusion rates points toward including antifibrinolytic therapy in standard TKA protocols. In our study, 40% of control patients and no antifibrinolytic patients required a transfusion—a stark contrast.

Although our antifibrinolytic group’s postoperative Hb levels were not statistically significantly higher, their being elevated illustrates the protective effect of intraoperative use of antifibrinolytics in TKA. This elevation in Hb levels is especially valid given the similarity of the antifibrinolytic and control patients’ preoperative Hb levels (P = .871) (Table 1). Other studies have shown similar upward trends in postoperative Hb levels, many of which were statistically significant.^5-8,10

Conclusion

This study showed that a single intraoperative 10-g dose of IV ACA significantly reduced perioperative blood loss and lowered blood transfusion rates in TKA. In addition, postoperative Hb levels were higher in the patients who received ACA than in patients who did not receive an antifibrinolytic. The positive effects of ACA were obtained without adverse events or complications, making use of this antifibrinolytic a relevant addition to TKA protocols.

During total knee arthroplasty (TKA), traditionally a thigh tourniquet is used to minimize blood loss. Although intraoperative blood loss is negligible, postoperative blood loss can be extensive, and patients often require blood transfusions. Transfusions expose patients to clinical risks and increase costs. Well-documented transfusion complications include allergic reaction, transfusion-related acute lung injury, transfusion-associated circulatory overload, venous thromboembolism, graft vs host disease, bloodborne infections, and immunomodulation.¹ Although measures are taken to reduce these risks, the costs associated with transfusions continue to escalate.²

Postoperative bleeding is attributed to fibrinolytic system activation. The antifibrinolytic agent aminocaproic acid (ACA), a synthetic analogue of the amino acid lysine, acts by competitively blocking the lysine-binding site of plasminogen, inhibiting fibrinolysis.³ Multiple studies have shown that ACA and a similar drug, tranexamic acid, can reduce postoperative blood loss when used intravenously in unilateral TKA.^4,5 However, more studies are needed to evaluate antifibrinolytic agents with comparative controls using standardized procedures and documented outcome measures. In addition, the majority of studies have used tranexamic acid rather than ACA, despite the lower cost and similar efficacy of ACA.^1,4 ACA is an inexpensive medication with a low risk profile, making it an attractive alternative to historical post-TKA management (which has a higher rate of blood transfusions) and a viable replacement in protocols already implementing tranexamic acid, the more expensive antifibrinolytic.^5,6 It has been proposed that ACA use reduces equipment (drain) costs, blood transfusion costs, exposure to complications of blood loss, and transfusion reactions and reduces or eliminates the need for costly medications, such as erythropoiesis-stimulating agents.

Kagoma and colleagues⁵ reported that antifibrinolytic agents may reduce bleeding by at least 300 mL and may reduce the need for transfusions by 50% or eliminate this need altogether. Other antifibrinolytic agents have been studied in unilateral TKA, with results showing decreased drainage and improved postoperative hemoglobin (Hb) levels.⁶

We conducted a study to evaluate the effectiveness of a single intraoperative dose of ACA in reducing postoperative blood loss and the need for blood transfusions with increased preservation of postoperative Hb levels.

Methods

In October 2011, Dr. Anderson initiated an intraoperative intravenous (IV) ACA protocol for primary unilateral TKA. Given the decreased drain output immediately observed, and patients’ increased postoperative Hb levels, a retrospective study was proposed. After obtaining full Institutional Review Board approval for the study, we retrospectively reviewed the medical charts of 50 consecutive patients who underwent primary unilateral TKA—the last 25 who had the surgery before the IV ACA protocol was initiated (control group) and the first 25 who were given the IV ACA medication during the surgery (antifibrinolytic group). Inclusion criteria were primary unilateral TKA, no bleeding dyscrasia, no history of anaphylactic response to antifibrinolytic agents, no history of deep vein thrombosis, and normal preoperative coagulation parameters, international normalized ratio (INR), and partial thromboplastin time. Exclusion criteria included lateral corner release, lateral retinacular release, combined extensive deep and superficial medial collateral ligament releases, and cardiac or peripheral stent in place.

Each surgery—a standard primary unilateral TKA with an intramedullary femoral component and an extramedullary tibial component—was performed by Dr. Anderson. Each component was cemented. Each patient underwent a posterior cruciate ligament release and/or a deep medial collateral ligament release. A well-padded thigh tourniquet was inflated before surgical incision, and it remained inflated until all postoperative surgical dressings were applied. Each patient in the antifibrinolytic group was given a 10-g dose of IV ACA at the start of implant cementation; the dose was administered over 10 minutes and was completely infused before tourniquet deflation. For each patient in the control group, a suction drain (Constavac, Stryker) was used. As postoperative drainage was so insignificant in the first 12 antifibrinolytic cases, use of the drain was then discontinued.

 

 

All patients received standard postoperative deep vein thrombosis prophylaxis in the form of warfarin in accordance with existing practice. Warfarin was given once a day starting the night of surgery and was continued until discharge based on daily INR values with an agreed-on target of 2.0. Thigh-high compression stockings and calf sequential compression devices were used in all cases. No patient in either group predonated blood or was given erythropoietin injections before or after surgery. Postoperative allogeneic transfusions were given to patients who were clinically symptomatic or short of breath; patients with hypotension uncorrectable with IV volume supplementation and an Hb level under 9.0 g/dL; and patients with an Hb level under 7.0 g/dL regardless of symptoms. All patients were monitored for postoperative adverse events and complications.

Postoperative blood loss (drain output), Hb levels on postoperative days 1 and 2 (POD-1, POD-2), blood transfusion amounts, and complications were recorded for all patients. Group means were compared with 2-sample t tests for independent samples. Data are reported as group means and SDs. All significance tests were 2-tailed, and statistical significance was set at P < .05.

Results

Fifty patients enrolled in the study: 25 in the control group and 25 in the antifibrinolytic group. Table 1 compares the main characteristics of the 2 groups. No significant differences were found between these groups for any of the characteristics considered.

There was significantly (P < .0001) more postoperative drainage in the control group: Mean drain output was 410.9 mL for the control group and 155.0 mL for the antifibrinolytic group (Table 2). Patients in the antifibrinolytic group did not receive any blood transfusions, whereas 40% of patients in the control group received transfusions (P = .022). On average, the transfused patients received 0.4 unit of packed red blood cells.

Although there was no statistically significant difference in POD-1 or POD-2 Hb levels between the antifibrinolytic and control groups, the antifibrinolytic group trended higher on POD-1 (11.1 g vs 10.7 g; P = .108) and POD-2 (11.5 g vs 10.2 g; P = .117) (Table 3). Mean Hb level was 8.1 g for control patients transfused on POD-1 and 7.9 g for control patients transfused on POD-2. For control patients who were not transfused, mean Hb level was 10.7 g on POD-1 and 10.2 g on POD-2.

There were no adverse events (eg, anaphylaxis, hypersensitivity) in either group, and there was no difference in incision drainage or returns to operating room between the groups.

Discussion

In TKA, a tourniquet is used to minimize intraoperative blood loss; postoperative bleeding, however, is often extensive. Both surgery and tourniquet use are reported to enhance local fibrinolytic activity within the limb.⁸ The synthetic antifibrinolytic ACA reduces blood loss by clot stabilization rather than by promotion of clot formation.⁸

In the present study, a single intraoperative dose of IV ACA administered in primary unilateral TKA significantly reduced postoperative wound drainage and eliminated the need for postoperative allogeneic blood transfusions. In addition, patients who received ACA had higher Hb levels on POD-1 and POD-2. These results are similar to those of other clinical trials in which external blood losses were measured.^4-7 The postoperative drain output differences (~250 mL) in our study are clinically relevant, as they indicate significant reductions in postoperative blood loss with the implementation of an antifibrinolytic operative protocol.

In a study by Ponnusamy and colleagues,¹ blood transfusion after orthopedic surgery accounted for 10% of all packed red blood cell transfusions, but use varied widely. National TKA transfusion rates vary from 4.3% to 63.8% among surgeons and hospitals.⁹ This evidence calls for standardization and critical review of practices to ensure more efficient use of blood products, effectively protecting patients from unneeded complications and reducing hospital costs. Mounting evidence supporting the efficacy of ACA in reducing perioperative blood loss and lowering postoperative blood transfusion rates points toward including antifibrinolytic therapy in standard TKA protocols. In our study, 40% of control patients and no antifibrinolytic patients required a transfusion—a stark contrast.

Although our antifibrinolytic group’s postoperative Hb levels were not statistically significantly higher, their being elevated illustrates the protective effect of intraoperative use of antifibrinolytics in TKA. This elevation in Hb levels is especially valid given the similarity of the antifibrinolytic and control patients’ preoperative Hb levels (P = .871) (Table 1). Other studies have shown similar upward trends in postoperative Hb levels, many of which were statistically significant.^5-8,10

Conclusion

This study showed that a single intraoperative 10-g dose of IV ACA significantly reduced perioperative blood loss and lowered blood transfusion rates in TKA. In addition, postoperative Hb levels were higher in the patients who received ACA than in patients who did not receive an antifibrinolytic. The positive effects of ACA were obtained without adverse events or complications, making use of this antifibrinolytic a relevant addition to TKA protocols.

During total knee arthroplasty (TKA), traditionally a thigh tourniquet is used to minimize blood loss. Although intraoperative blood loss is negligible, postoperative blood loss can be extensive, and patients often require blood transfusions. Transfusions expose patients to clinical risks and increase costs. Well-documented transfusion complications include allergic reaction, transfusion-related acute lung injury, transfusion-associated circulatory overload, venous thromboembolism, graft vs host disease, bloodborne infections, and immunomodulation.¹ Although measures are taken to reduce these risks, the costs associated with transfusions continue to escalate.²

Postoperative bleeding is attributed to fibrinolytic system activation. The antifibrinolytic agent aminocaproic acid (ACA), a synthetic analogue of the amino acid lysine, acts by competitively blocking the lysine-binding site of plasminogen, inhibiting fibrinolysis.³ Multiple studies have shown that ACA and a similar drug, tranexamic acid, can reduce postoperative blood loss when used intravenously in unilateral TKA.^4,5 However, more studies are needed to evaluate antifibrinolytic agents with comparative controls using standardized procedures and documented outcome measures. In addition, the majority of studies have used tranexamic acid rather than ACA, despite the lower cost and similar efficacy of ACA.^1,4 ACA is an inexpensive medication with a low risk profile, making it an attractive alternative to historical post-TKA management (which has a higher rate of blood transfusions) and a viable replacement in protocols already implementing tranexamic acid, the more expensive antifibrinolytic.^5,6 It has been proposed that ACA use reduces equipment (drain) costs, blood transfusion costs, exposure to complications of blood loss, and transfusion reactions and reduces or eliminates the need for costly medications, such as erythropoiesis-stimulating agents.

Kagoma and colleagues⁵ reported that antifibrinolytic agents may reduce bleeding by at least 300 mL and may reduce the need for transfusions by 50% or eliminate this need altogether. Other antifibrinolytic agents have been studied in unilateral TKA, with results showing decreased drainage and improved postoperative hemoglobin (Hb) levels.⁶

We conducted a study to evaluate the effectiveness of a single intraoperative dose of ACA in reducing postoperative blood loss and the need for blood transfusions with increased preservation of postoperative Hb levels.

Methods

In October 2011, Dr. Anderson initiated an intraoperative intravenous (IV) ACA protocol for primary unilateral TKA. Given the decreased drain output immediately observed, and patients’ increased postoperative Hb levels, a retrospective study was proposed. After obtaining full Institutional Review Board approval for the study, we retrospectively reviewed the medical charts of 50 consecutive patients who underwent primary unilateral TKA—the last 25 who had the surgery before the IV ACA protocol was initiated (control group) and the first 25 who were given the IV ACA medication during the surgery (antifibrinolytic group). Inclusion criteria were primary unilateral TKA, no bleeding dyscrasia, no history of anaphylactic response to antifibrinolytic agents, no history of deep vein thrombosis, and normal preoperative coagulation parameters, international normalized ratio (INR), and partial thromboplastin time. Exclusion criteria included lateral corner release, lateral retinacular release, combined extensive deep and superficial medial collateral ligament releases, and cardiac or peripheral stent in place.

Each surgery—a standard primary unilateral TKA with an intramedullary femoral component and an extramedullary tibial component—was performed by Dr. Anderson. Each component was cemented. Each patient underwent a posterior cruciate ligament release and/or a deep medial collateral ligament release. A well-padded thigh tourniquet was inflated before surgical incision, and it remained inflated until all postoperative surgical dressings were applied. Each patient in the antifibrinolytic group was given a 10-g dose of IV ACA at the start of implant cementation; the dose was administered over 10 minutes and was completely infused before tourniquet deflation. For each patient in the control group, a suction drain (Constavac, Stryker) was used. As postoperative drainage was so insignificant in the first 12 antifibrinolytic cases, use of the drain was then discontinued.

 

 

All patients received standard postoperative deep vein thrombosis prophylaxis in the form of warfarin in accordance with existing practice. Warfarin was given once a day starting the night of surgery and was continued until discharge based on daily INR values with an agreed-on target of 2.0. Thigh-high compression stockings and calf sequential compression devices were used in all cases. No patient in either group predonated blood or was given erythropoietin injections before or after surgery. Postoperative allogeneic transfusions were given to patients who were clinically symptomatic or short of breath; patients with hypotension uncorrectable with IV volume supplementation and an Hb level under 9.0 g/dL; and patients with an Hb level under 7.0 g/dL regardless of symptoms. All patients were monitored for postoperative adverse events and complications.

Postoperative blood loss (drain output), Hb levels on postoperative days 1 and 2 (POD-1, POD-2), blood transfusion amounts, and complications were recorded for all patients. Group means were compared with 2-sample t tests for independent samples. Data are reported as group means and SDs. All significance tests were 2-tailed, and statistical significance was set at P < .05.

Results

Fifty patients enrolled in the study: 25 in the control group and 25 in the antifibrinolytic group. Table 1 compares the main characteristics of the 2 groups. No significant differences were found between these groups for any of the characteristics considered.

There was significantly (P < .0001) more postoperative drainage in the control group: Mean drain output was 410.9 mL for the control group and 155.0 mL for the antifibrinolytic group (Table 2). Patients in the antifibrinolytic group did not receive any blood transfusions, whereas 40% of patients in the control group received transfusions (P = .022). On average, the transfused patients received 0.4 unit of packed red blood cells.

Although there was no statistically significant difference in POD-1 or POD-2 Hb levels between the antifibrinolytic and control groups, the antifibrinolytic group trended higher on POD-1 (11.1 g vs 10.7 g; P = .108) and POD-2 (11.5 g vs 10.2 g; P = .117) (Table 3). Mean Hb level was 8.1 g for control patients transfused on POD-1 and 7.9 g for control patients transfused on POD-2. For control patients who were not transfused, mean Hb level was 10.7 g on POD-1 and 10.2 g on POD-2.

There were no adverse events (eg, anaphylaxis, hypersensitivity) in either group, and there was no difference in incision drainage or returns to operating room between the groups.

Discussion

In TKA, a tourniquet is used to minimize intraoperative blood loss; postoperative bleeding, however, is often extensive. Both surgery and tourniquet use are reported to enhance local fibrinolytic activity within the limb.⁸ The synthetic antifibrinolytic ACA reduces blood loss by clot stabilization rather than by promotion of clot formation.⁸

In the present study, a single intraoperative dose of IV ACA administered in primary unilateral TKA significantly reduced postoperative wound drainage and eliminated the need for postoperative allogeneic blood transfusions. In addition, patients who received ACA had higher Hb levels on POD-1 and POD-2. These results are similar to those of other clinical trials in which external blood losses were measured.^4-7 The postoperative drain output differences (~250 mL) in our study are clinically relevant, as they indicate significant reductions in postoperative blood loss with the implementation of an antifibrinolytic operative protocol.

In a study by Ponnusamy and colleagues,¹ blood transfusion after orthopedic surgery accounted for 10% of all packed red blood cell transfusions, but use varied widely. National TKA transfusion rates vary from 4.3% to 63.8% among surgeons and hospitals.⁹ This evidence calls for standardization and critical review of practices to ensure more efficient use of blood products, effectively protecting patients from unneeded complications and reducing hospital costs. Mounting evidence supporting the efficacy of ACA in reducing perioperative blood loss and lowering postoperative blood transfusion rates points toward including antifibrinolytic therapy in standard TKA protocols. In our study, 40% of control patients and no antifibrinolytic patients required a transfusion—a stark contrast.

Although our antifibrinolytic group’s postoperative Hb levels were not statistically significantly higher, their being elevated illustrates the protective effect of intraoperative use of antifibrinolytics in TKA. This elevation in Hb levels is especially valid given the similarity of the antifibrinolytic and control patients’ preoperative Hb levels (P = .871) (Table 1). Other studies have shown similar upward trends in postoperative Hb levels, many of which were statistically significant.^5-8,10

Conclusion

This study showed that a single intraoperative 10-g dose of IV ACA significantly reduced perioperative blood loss and lowered blood transfusion rates in TKA. In addition, postoperative Hb levels were higher in the patients who received ACA than in patients who did not receive an antifibrinolytic. The positive effects of ACA were obtained without adverse events or complications, making use of this antifibrinolytic a relevant addition to TKA protocols.

After anterior cruciate ligament (ACL) reconstruction, women younger than age 25 with a graft size of <8 mm have an increased change of re-tearing their ACL, according to the results of a study presented at the 2016 annual meeting of the American Orthopedic Society of Sports Medicine.

Researchers studied 503 athletes (235 women and 268 men; average age 27) undergoing primary, autograft hamstring ACL reconstruction. The surgeries were all performed at a single center by a single surgeon between September through December 2012. Patients were followed for 2 years. Overall, the rate of re-tears was 6% and the mean graft size was 7.9 mm.

Graft size <8 mm and age < 25 years were significantly predictive of re‐tear. Female sex was correlated with re‐tear but was not significant.

After anterior cruciate ligament (ACL) reconstruction, women younger than age 25 with a graft size of <8 mm have an increased change of re-tearing their ACL, according to the results of a study presented at the 2016 annual meeting of the American Orthopedic Society of Sports Medicine.

Researchers studied 503 athletes (235 women and 268 men; average age 27) undergoing primary, autograft hamstring ACL reconstruction. The surgeries were all performed at a single center by a single surgeon between September through December 2012. Patients were followed for 2 years. Overall, the rate of re-tears was 6% and the mean graft size was 7.9 mm.

Graft size <8 mm and age < 25 years were significantly predictive of re‐tear. Female sex was correlated with re‐tear but was not significant.

After anterior cruciate ligament (ACL) reconstruction, women younger than age 25 with a graft size of <8 mm have an increased change of re-tearing their ACL, according to the results of a study presented at the 2016 annual meeting of the American Orthopedic Society of Sports Medicine.

Researchers studied 503 athletes (235 women and 268 men; average age 27) undergoing primary, autograft hamstring ACL reconstruction. The surgeries were all performed at a single center by a single surgeon between September through December 2012. Patients were followed for 2 years. Overall, the rate of re-tears was 6% and the mean graft size was 7.9 mm.

Graft size <8 mm and age < 25 years were significantly predictive of re‐tear. Female sex was correlated with re‐tear but was not significant.

Nearly 2% of patients who undergo total knee arthroplasty (TKA) or total hip arthroplasty (THA) develop a periprosthetic joint infection (PJI) within 20 years of surgery, and 41% of these infections occur within the first 2 years.¹ PJI is the most common cause of TKA failure and the third leading complication of THA.² The estimated total hospital cost of treating PJI increased from $320 million in 2001 to $566 million in 2009, which can be extrapolated to $1.62 billion in 2020.³ By 2030, the projected increase in demand for TKA and THA will be 673% and 174% of what it was in 2005, respectively.⁴ Treatment of PJI of the knee is estimated to cost 3 to 4 times more than a primary TKA, and the cost of revision THA for PJI is almost $6000 more than that of revision TKA for PJI.³

In this article, we review the numerous preoperative, intraoperative, and postoperative methods of decreasing PJI incidence after total joint arthroplasty (TJA).

Preoperative Risk Prevention

Medical Comorbidities

Preoperative medical optimization is a key element in PJI prevention (Table 1). An American Society of Anesthesiologists classification score of 3 or more has been associated with doubled risk for surgical site infections (SSIs) after THA.5 Autoimmune conditions confer a particularly higher risk. In a retrospective double-cohort study of 924 subjects, Bongartz and colleagues⁶ found that, compared with osteoarthritis, rheumatoid arthritis tripled the risk of PJI. Small case series originally suggested a higher risk of PJI in patients with psoriasis,^7,8 but more recent studies have contradicted that finding.^9,10 Nevertheless, psoriatic plaques have elevated bacterial counts,¹¹ and planned incisions should circumvent these areas.

Diabetes mellitus is a clear risk factor for PJI.^12-16 Regarding whether preoperative glucose control affects risk, findings have been mixed. Mraovic and colleagues¹⁷ showed preoperative hyperglycemia to be an independent risk factor; Jämsen and colleagues,¹⁵ in a single-center analysis of more than 7000 TJAs, suggested preoperative blood glucose levels were not independently associated with PJI; and Iorio and colleagues¹⁶ found no association between surgical infections and hemoglobin A1c levels.

TJA incidence is higher in patients with chronic kidney disease (CKD) than in the general population.¹⁸ Dialysis users have a post-THA PJI rate as high as 13% to 19%.^19,20 Early clinical data suggested that outcomes are improved in dialysis users who undergo renal transplant, but this finding recently has been questioned.^19,21 Deegan and colleagues²² found an increased PJA rate of 3.5% even in low-level CKD (stage 1, 2, or 3), but this may be confounded by the increased association of CKD with other PJI-predisposing comorbidities.

Given a higher incidence of urinary tract infections (UTIs) among patients with PJI, some surgeons think UTIs predispose to PJIs by hematogenous seeding.^12,23,24 Symptomatic UTIs should be cleared before surgery and confirmed on urinalysis. Obstructive symptoms should prompt urologic evaluation. As asymptomatic pyuria and bacteriuria (colony counts, >1 × 105/mL) do not predispose to PJI, patients without symptoms do not require intervention.^25,26 Past history of malignancy may also have a role in PJI. In a case-control study of the Mayo Clinic arthroplasty experience from 1969 to 1991, Berbari and colleagues¹ found an association between malignancy and PJI (odds ratio, 2.4). They theorized the immunosuppressive effects of cancer treatment might be responsible for this increased risk.

 

 

Immunocompromising Medications

Immunocompromising medications are modifiable and should be adjusted before surgery. Stopping any disease-modifying antirheumatic drug (DMARD) more than 4 weeks before surgery is not recommended.²⁷

Corticosteroid use can lead to immunosuppression and increased protein catabolism, which impairs soft-tissue healing. To avoid flares or adrenal insufficiency, however, chronic corticosteroid users should continue their regular doses perioperatively.²⁸ On the day of surgery, they should also receive a stress dose of hydrocortisone 50 to 75 mg (for primary arthroplasty) or 100 to 150 mg (for revision arthroplasty), followed by expeditious tapering over 1 to 2 days.²⁹ DMARDs are increasingly used by rheumatologists. One of the most effective DMARDs is methotrexate. Despite its immunocompromising activity, methotrexate should be continued perioperatively, as stopping for even 2 days may increase flare-related complications.³⁰ Hydroxychloroquine can be continued perioperatively and has even been shown, by Johnson and Charnley,³¹ to prevent deep vein thromboses. Sulfasalazine can also be continued perioperatively—but with caution, as it may elevate international normalized ratio (INR) levels in patients receiving warfarin.²⁹ Most other DMARDs should be temporarily discontinued. Leflunomide and interleukin 1 antagonists, such as anakinra, should be stopped 1 to 2 days before surgery and restarted 10 to 14 days after surgery.²⁹ Rituximab should be stopped 1 week before surgery and restarted 10 to 14 days after surgery. Tumor necrosis factor α inhibitors should be discontinued for 2 half-lives before and after surgery.³² Etanercept has a half-life of 3 to 5 days; infliximab, 8 to 10 days; and adalimumab, 10 to 13 days. Most surgeons schedule surgery for the end of a dosing cycle and discontinue these biologic agents for another 10 to 14 days after surgery.

Metabolic Factors

Obese patients are susceptible to longer surgeries, more extensive dissection, poorly vascularized subcutaneous tissue, and higher requirements of weight-adjusted antibiotic dosing.¹³ Body mass index (BMI) of 40 kg/m² or more (morbid obesity) and BMI over 50 kg/m² have been associated with 9 times and 21.3 times increased risk of PJI, respectively.^13,14 Delaying surgery with dietary consultation has been suggested,^33,34 and bariatric surgery before TKA may decrease infection rates by 3.5 times.³⁵

Nutritional markers are considered before arthroplasty. According to most laboratories, a serum transferrin level under 200 mg/dL, albumin level under 3.5 g/dL, and total lymphocyte count under 1500 cells/mm³ indicate malnourishment, which can increase the incidence of wound complications by 5 to 7 times.³⁶ Patients should also have sufficient protein, vitamin, and mineral supplementation, particularly vitamins A and C, zinc, and copper.³⁷Smokers who cease smoking at least 4 to 6 weeks before surgery lower their wound complication rate by up to 26%.^38,39 When nicotine leaves the bloodstream, vasodilation occurs, oxygenation improves, and the immune system recovers.³⁹ Studies have found more SSIs in patients who abuse alcohol,40 and numerous authors have confirmed this finding in the arthroplasty population.^24,41,42 Alcohol inhibits platelet function and may predispose to a postoperative hematoma. In contrast to smoking cessation evidence, evidence regarding alcohol interventions in preventing postoperative infections is less conclusive.^43,44

MRSA Colonization

Methicillin-resistant Staphylococcus aureus (MRSA) is a particularly difficult bacterium to eradicate in PJI. As the mean cost of treating a single case of MRSA-related prosthetic infection is $107,264 vs $68,053 for susceptible strains,45,46 many infection-containment strategies focus on addressing benign MRSA colonization before surgery.

MRSA is present in the nares of 25 million people in the United States. Nasal colonization increases the risk of bacteremia 4-fold⁴⁷ and SSI 2- to 9-fold.^48,49 Nasal swabs are analyzed with either a rapid polymerase chain reaction (PCR) test, which provides results in 2 hours, or a bacterial culture, which provides results in 1 to 4 days. The PCR test is more expensive.

Eradication of MRSA colonization is increasingly prevalent. Several Scandinavian countries have instituted strict practices by which patients are denied elective surgery until negative nasal swabs are obtained.⁴⁹ Nasal decontamination is one method of colonization reduction. Topical mupirocin, which yields eradication in 91% of nasal carriers immediately after treatment and in 87% after 4 weeks,⁵⁰ is effective in reducing SSI rates only when used in conjunction with a body wash, which is used to clean the axilla and groin.⁵¹ There is no consensus on optimal timing, but Bode and colleagues⁵² found a significant decrease in deep SSIs when decontamination occurred just 24 hours before surgery.

 

 

Povidone-iodine showers went out of favor with the realization that chlorhexidine gluconate acts longer on the skin surface.^53,54 Preoperative showers involve rinsing with liquid chlorhexidine soap 24 to 48 hours before surgery. However, chlorhexidine binds preferentially to the cotton in washcloths instead of the skin. Edmiston and colleagues^54,55 found that 4% chlorhexidine liquid soaps achieve much lower skin chlorhexidine concentrations than 2% polyester cloths do. Use of these “chlorhexidine wipes” the night before and the day of surgery has decreased PJI after TKA from 2.2% to 0.6%.^56,57

Intraoperative Risk Prevention

Preparation

Which preoperative antibiotic to use is one of the first operative considerations in PJI prophylaxis (Table 2). Cefazolin is recommended as a first-line agent for its excellent soft-tissue penetration, long half-life, and activity against gram-positive bacteria such as skin flora.⁵⁸ Clindamycin may be considered for patients allergic to β-lactam antibiotics. Vancomycin may be considered for adjunctive use with cephalosporins in cases of known MRSA colonization. Vancomycin infusion should be started earlier than infusion with other antibiotics, as vancomycin must be infused slowly and takes longer to become therapeutic.

Antibiotic dosing should be based on local antibiograms, adjusted dosing weight, or BMI.⁵⁹ For revision arthroplasty, preoperative prophylaxis should not be stopped out of fear of affecting operative cultures.⁶⁰ Some surgeons pause antibiotic use if a preoperative joint aspirate has not been obtained. Infusion within 1 hour of incision is part of the pay-for-performance guidelines established by the US Centers for Medicare & Medicaid Services.⁶¹ An antibiotic should be redosed if the operation will take longer than 2 half-lives of the drug.⁵⁹ Surgeons should consider administering a dose every 4 hours or whenever blood loss exceeds 1000 mL.⁶² Engesæter and colleagues⁶³ found that antibiotic prophylaxis was most effective given 4 times perioperatively (1 time before surgery, 3 times after surgery). Postoperative antibiotics should not be administered longer than 24 hours, as prolonged dosing confers no benefit.⁵⁸ Operating room conditions must be optimized for prophylaxis. More people and operating room traffic in nonsterile corridors increase contamination of instruments open to air.⁶⁴ Laminar airflow systems are commonly used. Although there is little dispute that laminar flow decreases the bacterial load of air, there are mixed results regarding its benefit in preventing PJI.^65-68 Skin preparation may address patient risk factors. Hair clipping is preferred to shaving, which may cause microabrasions and increased susceptibility to skin flora.69 Patients should be prepared with antiseptic solution. One randomized controlled trial found that 2% chlorhexidine gluconate mixed with 70% isopropyl alcohol was superior to 10% povidone-iodine in preventing SSIs.⁷⁰ However, a recent cohort study showed a lower rate of superficial wound infections when 1% povidone-iodine (vs 0.5% chlorhexidine) was used with alcohol.⁷¹ This finding may indicate the need for alcohol preparation, higher concentrations of chlorhexidine, or both.

Proper scrubbing and protective gear are needed to reduce surgeon risk factors. Hand washing is a routine part of any surgery. Alcohol-based hand scrubs are as effective as hand scrubbing.65 They reduce local skin flora by 95% immediately and by 99% with repeated applications.⁷² Lidwell and colleagues⁷³ found a 75% reduction in infection when body exhaust suits were used in combination with laminar flow in a multicenter randomized controlled trial of 8052 patients. Sterile draping with impermeable drapes should be done over properly prepared skin. Ioban drapes (3M) are often used as a protective barrier. Interestingly, a Cochrane review found no benefit in using plastic adhesives impregnated with iodine over sterilely prepared skin.⁷⁴

 

 

Operative Considerations

Surgical gloves become contaminated in almost one third of cases, half the time during draping.⁷⁵ For this reason, many surgeons change gloves after draping. In addition, double gloving prevents a breech of aseptic technique should the outer glove become perforated.⁷⁶ Demircay and colleagues⁷⁷ assessed double latex gloving in arthroplasty and found the outer and inner gloves perforated in 18.4% and 8.4% of cases, respectively. Punctures are most common along the nondominant index finger, and then the dominant thumb.^77,78 Perforation is more common when 2 latex gloves are worn—vs 1 latex glove plus an outer cloth glove—and the chance of perforation increases with surgery duration. The inner glove may become punctured in up to 100% of operations that last over 3 hours.⁷⁹ Although Dodds and colleagues⁸⁰ found no change in bacterial counts on surgeons’ hands or gloves after perforation, precautions are still recommended. Al-Maiyah and colleagues⁸¹ went as far as to recommend glove changes at 20-minute intervals and before cementation.

Surgical instruments can be sources of contamination. Some authors change the suction tip every hour to minimize the risk of deep wound infection.^82-85 Others change it before femoral canal preparation and prosthesis insertion during THA.⁸⁶ The splash basin is frequently contaminated, and instruments placed in it should not be returned to the operative field.⁸⁷ Hargrove and colleagues⁸⁸ suggested pulsatile lavage decreases PJI more than bulb syringe irrigation does, whereas others argued that high-pressure lavage allows bacteria to penetrate more deeply, which could lead to retention of more bacteria.⁸⁹ Minimizing operating room time was found by Kurtz and colleagues⁹⁰ and Peersman and colleagues⁹¹ to decrease PJI incidence. Carroll and colleagues⁷¹ correlated longer tourniquet use with a higher rate of infection after TKA; proposed mechanisms include local tissue hypoxia and lowered concentrations of prophylactic antibiotics.

Similarly, minimizing blood loss and transfusion needs is another strategy for preventing infection. Allogenic transfusion may increase the risk of PJI 2 times.^23,71,92 The mechanism seems to be immune system modulation by allogenic blood, which impairs microcirculation and oxygen delivery at the surgical site.^23,75 Transfusions should be approached with caution, and consideration given to preoperative optimization and autologous blood donation. Cherian and colleagues⁹³ reviewed different blood management strategies and found preoperative iron therapy, intravenous erythropoietin, and autologous blood donation to be equally effective in reducing the need for allogenic transfusions. Numerous studies of tranexamic acid, thrombin-based hemostatic matrix (Floseal; Baxter Inc), and bipolar sealer with radiofrequency ablation (Aquamantys; Medtronic Inc) have found no alterations in infection rates, but most have used calculated blood loss, not PJI, as the primary endpoint.^94-105 Antibiotic cement also can be used to block infection.^63,106-110 Although liquid gentamicin may weaken bone cement,¹¹¹ most antibiotics, including powdered tobramycin and vancomycin, do not weaken its fatigue strength.^111-114 A recent meta-analysis by Parvizi and colleagues¹¹⁵ revealed that deep infection rates dropped from 2.3% to 1.2% with use of antibiotic cement for primary THAs. Cummins and colleagues,¹¹⁶ however, reported the limited cost-effectiveness of antibiotic cement in primary arthroplasty. Performing povidone-iodine lavage at the end of the case may be a more inexpensive alternative. Brown and colleagues¹¹⁷ found that rinsing with dilute povidone-iodine (.35%) for 3 minutes significantly decreased the incidence of PJI.

Closure techniques and sutures have been a focus of much of the recent literature. Winiarsky and colleagues³⁴ advocated using a longer incision for obese patients and augmenting closure in fattier areas with vertical mattress retention sutures, which are removed after 5 days. A barbed monofilament suture (Quill; Angiotech Inc) is gaining in popularity. Laboratory research has shown that bacteria adhere less to barbed monofilament sutures than to braided sutures.¹¹⁸ Smith and colleagues¹¹⁹ found a statistically nonsignificant higher rate of wound complications with barbed monofilament sutures, whereas Ting and colleagues120 found no difference in complications. These studies were powered to detect differences in time and cost, not postoperative complications. Skin adhesive (Dermabond; Ethicon Inc), also used in closure, may be superior to staples in avoiding superficial skin abscesses.¹²¹ Although expensive, silver-impregnated dressing has antimicrobial activity that reduces PJI incidence by up to 74%.¹²² One brand of this dressing (Aquacel; ConvaTec Inc) has a polyurethane waterproof barrier that allows it to be worn for 7 days.

 

 

Three factors commonly mentioned in PJI prevention show little supporting evidence. Drains, which are often used, may create a passage for postoperative infection and are associated with increased transfusion needs.^123,124 Adding antibiotics to irrigation solution¹²⁵ and routinely changing scalpel blades^126-129 also have little supporting evidence. In 2014, the utility of changing scalpel blades after incision was studied by Lee and colleagues,¹³⁰ who reported persistence of Propionibacterium acnes in the dermal layer after skin preparation. Their study, however, was isolated to the upper back region, not the hip or knee.

Postoperative Risk Prevention

Most arthroplasty patients receive anticoagulation after surgery, but it must be used with caution. Large hematomas can predispose to wound complications. Parvizi and colleagues¹³¹ associated wound drainage, hematoma, and subsequent PJI with an INR above 1.5 in the early postoperative period. Therefore, balanced anticoagulation is crucial. Postoperative glucose control is also essential, particularly for patients with diabetes. Although preoperative blood glucose levels may or may not affect PJI risk,^15,17,132 postoperative blood glucose levels of 126 mg/dL or higher are strongly associated with joint infections.¹³³ Even nondiabetic patients with postoperative morning levels over 140 mg/dL are 3 times more likely to develop an infection.¹⁷

Efforts should be made to discharge patients as soon as it is safe to do so. With longer hospital stays, patients are more exposed to nosocomial organisms and increased antibiotic resistance.^5,23,134 Outpatient antibiotics should be considered for dental, gastrointestinal, and genitourinary procedures. Oral antibiotic prophylaxis is controversial, as there is some evidence that dental procedures increase the risk of PJI only minimally.^10,135-138

Conclusion

PJI is a potentially devastating complication of TJA. For this reason, much research has been devoted to proper diagnosis and treatment. Although the literature on PJI prophylaxis is abundant, there is relatively little consensus on appropriate PJI precautions. Preoperative considerations should include medical comorbidities, use of immunocompromising medications, obesity, nutritional factors, smoking, alcohol use, and MRSA colonization. Surgeons must have a consistent intraoperative method of antibiotic administration, skin preparation, scrubbing, draping, gloving, instrument exchange, blood loss management, cementing, and closure. In addition, monitoring of postoperative anticoagulation and blood glucose management is important. Having a thorough understanding of PJI risk factors may help reduce the incidence of this devastating complication.

Nearly 2% of patients who undergo total knee arthroplasty (TKA) or total hip arthroplasty (THA) develop a periprosthetic joint infection (PJI) within 20 years of surgery, and 41% of these infections occur within the first 2 years.¹ PJI is the most common cause of TKA failure and the third leading complication of THA.² The estimated total hospital cost of treating PJI increased from $320 million in 2001 to $566 million in 2009, which can be extrapolated to $1.62 billion in 2020.³ By 2030, the projected increase in demand for TKA and THA will be 673% and 174% of what it was in 2005, respectively.⁴ Treatment of PJI of the knee is estimated to cost 3 to 4 times more than a primary TKA, and the cost of revision THA for PJI is almost $6000 more than that of revision TKA for PJI.³

In this article, we review the numerous preoperative, intraoperative, and postoperative methods of decreasing PJI incidence after total joint arthroplasty (TJA).

Preoperative Risk Prevention

Medical Comorbidities

Preoperative medical optimization is a key element in PJI prevention (Table 1). An American Society of Anesthesiologists classification score of 3 or more has been associated with doubled risk for surgical site infections (SSIs) after THA.5 Autoimmune conditions confer a particularly higher risk. In a retrospective double-cohort study of 924 subjects, Bongartz and colleagues⁶ found that, compared with osteoarthritis, rheumatoid arthritis tripled the risk of PJI. Small case series originally suggested a higher risk of PJI in patients with psoriasis,^7,8 but more recent studies have contradicted that finding.^9,10 Nevertheless, psoriatic plaques have elevated bacterial counts,¹¹ and planned incisions should circumvent these areas.

Diabetes mellitus is a clear risk factor for PJI.^12-16 Regarding whether preoperative glucose control affects risk, findings have been mixed. Mraovic and colleagues¹⁷ showed preoperative hyperglycemia to be an independent risk factor; Jämsen and colleagues,¹⁵ in a single-center analysis of more than 7000 TJAs, suggested preoperative blood glucose levels were not independently associated with PJI; and Iorio and colleagues¹⁶ found no association between surgical infections and hemoglobin A1c levels.

TJA incidence is higher in patients with chronic kidney disease (CKD) than in the general population.¹⁸ Dialysis users have a post-THA PJI rate as high as 13% to 19%.^19,20 Early clinical data suggested that outcomes are improved in dialysis users who undergo renal transplant, but this finding recently has been questioned.^19,21 Deegan and colleagues²² found an increased PJA rate of 3.5% even in low-level CKD (stage 1, 2, or 3), but this may be confounded by the increased association of CKD with other PJI-predisposing comorbidities.

Given a higher incidence of urinary tract infections (UTIs) among patients with PJI, some surgeons think UTIs predispose to PJIs by hematogenous seeding.^12,23,24 Symptomatic UTIs should be cleared before surgery and confirmed on urinalysis. Obstructive symptoms should prompt urologic evaluation. As asymptomatic pyuria and bacteriuria (colony counts, >1 × 105/mL) do not predispose to PJI, patients without symptoms do not require intervention.^25,26 Past history of malignancy may also have a role in PJI. In a case-control study of the Mayo Clinic arthroplasty experience from 1969 to 1991, Berbari and colleagues¹ found an association between malignancy and PJI (odds ratio, 2.4). They theorized the immunosuppressive effects of cancer treatment might be responsible for this increased risk.

 

 

Immunocompromising Medications

Immunocompromising medications are modifiable and should be adjusted before surgery. Stopping any disease-modifying antirheumatic drug (DMARD) more than 4 weeks before surgery is not recommended.²⁷

Corticosteroid use can lead to immunosuppression and increased protein catabolism, which impairs soft-tissue healing. To avoid flares or adrenal insufficiency, however, chronic corticosteroid users should continue their regular doses perioperatively.²⁸ On the day of surgery, they should also receive a stress dose of hydrocortisone 50 to 75 mg (for primary arthroplasty) or 100 to 150 mg (for revision arthroplasty), followed by expeditious tapering over 1 to 2 days.²⁹ DMARDs are increasingly used by rheumatologists. One of the most effective DMARDs is methotrexate. Despite its immunocompromising activity, methotrexate should be continued perioperatively, as stopping for even 2 days may increase flare-related complications.³⁰ Hydroxychloroquine can be continued perioperatively and has even been shown, by Johnson and Charnley,³¹ to prevent deep vein thromboses. Sulfasalazine can also be continued perioperatively—but with caution, as it may elevate international normalized ratio (INR) levels in patients receiving warfarin.²⁹ Most other DMARDs should be temporarily discontinued. Leflunomide and interleukin 1 antagonists, such as anakinra, should be stopped 1 to 2 days before surgery and restarted 10 to 14 days after surgery.²⁹ Rituximab should be stopped 1 week before surgery and restarted 10 to 14 days after surgery. Tumor necrosis factor α inhibitors should be discontinued for 2 half-lives before and after surgery.³² Etanercept has a half-life of 3 to 5 days; infliximab, 8 to 10 days; and adalimumab, 10 to 13 days. Most surgeons schedule surgery for the end of a dosing cycle and discontinue these biologic agents for another 10 to 14 days after surgery.

Metabolic Factors

Obese patients are susceptible to longer surgeries, more extensive dissection, poorly vascularized subcutaneous tissue, and higher requirements of weight-adjusted antibiotic dosing.¹³ Body mass index (BMI) of 40 kg/m² or more (morbid obesity) and BMI over 50 kg/m² have been associated with 9 times and 21.3 times increased risk of PJI, respectively.^13,14 Delaying surgery with dietary consultation has been suggested,^33,34 and bariatric surgery before TKA may decrease infection rates by 3.5 times.³⁵

Nutritional markers are considered before arthroplasty. According to most laboratories, a serum transferrin level under 200 mg/dL, albumin level under 3.5 g/dL, and total lymphocyte count under 1500 cells/mm³ indicate malnourishment, which can increase the incidence of wound complications by 5 to 7 times.³⁶ Patients should also have sufficient protein, vitamin, and mineral supplementation, particularly vitamins A and C, zinc, and copper.³⁷Smokers who cease smoking at least 4 to 6 weeks before surgery lower their wound complication rate by up to 26%.^38,39 When nicotine leaves the bloodstream, vasodilation occurs, oxygenation improves, and the immune system recovers.³⁹ Studies have found more SSIs in patients who abuse alcohol,40 and numerous authors have confirmed this finding in the arthroplasty population.^24,41,42 Alcohol inhibits platelet function and may predispose to a postoperative hematoma. In contrast to smoking cessation evidence, evidence regarding alcohol interventions in preventing postoperative infections is less conclusive.^43,44

MRSA Colonization

Methicillin-resistant Staphylococcus aureus (MRSA) is a particularly difficult bacterium to eradicate in PJI. As the mean cost of treating a single case of MRSA-related prosthetic infection is $107,264 vs $68,053 for susceptible strains,45,46 many infection-containment strategies focus on addressing benign MRSA colonization before surgery.

MRSA is present in the nares of 25 million people in the United States. Nasal colonization increases the risk of bacteremia 4-fold⁴⁷ and SSI 2- to 9-fold.^48,49 Nasal swabs are analyzed with either a rapid polymerase chain reaction (PCR) test, which provides results in 2 hours, or a bacterial culture, which provides results in 1 to 4 days. The PCR test is more expensive.

Eradication of MRSA colonization is increasingly prevalent. Several Scandinavian countries have instituted strict practices by which patients are denied elective surgery until negative nasal swabs are obtained.⁴⁹ Nasal decontamination is one method of colonization reduction. Topical mupirocin, which yields eradication in 91% of nasal carriers immediately after treatment and in 87% after 4 weeks,⁵⁰ is effective in reducing SSI rates only when used in conjunction with a body wash, which is used to clean the axilla and groin.⁵¹ There is no consensus on optimal timing, but Bode and colleagues⁵² found a significant decrease in deep SSIs when decontamination occurred just 24 hours before surgery.

 

 

Povidone-iodine showers went out of favor with the realization that chlorhexidine gluconate acts longer on the skin surface.^53,54 Preoperative showers involve rinsing with liquid chlorhexidine soap 24 to 48 hours before surgery. However, chlorhexidine binds preferentially to the cotton in washcloths instead of the skin. Edmiston and colleagues^54,55 found that 4% chlorhexidine liquid soaps achieve much lower skin chlorhexidine concentrations than 2% polyester cloths do. Use of these “chlorhexidine wipes” the night before and the day of surgery has decreased PJI after TKA from 2.2% to 0.6%.^56,57

Intraoperative Risk Prevention

Preparation

Which preoperative antibiotic to use is one of the first operative considerations in PJI prophylaxis (Table 2). Cefazolin is recommended as a first-line agent for its excellent soft-tissue penetration, long half-life, and activity against gram-positive bacteria such as skin flora.⁵⁸ Clindamycin may be considered for patients allergic to β-lactam antibiotics. Vancomycin may be considered for adjunctive use with cephalosporins in cases of known MRSA colonization. Vancomycin infusion should be started earlier than infusion with other antibiotics, as vancomycin must be infused slowly and takes longer to become therapeutic.

Antibiotic dosing should be based on local antibiograms, adjusted dosing weight, or BMI.⁵⁹ For revision arthroplasty, preoperative prophylaxis should not be stopped out of fear of affecting operative cultures.⁶⁰ Some surgeons pause antibiotic use if a preoperative joint aspirate has not been obtained. Infusion within 1 hour of incision is part of the pay-for-performance guidelines established by the US Centers for Medicare & Medicaid Services.⁶¹ An antibiotic should be redosed if the operation will take longer than 2 half-lives of the drug.⁵⁹ Surgeons should consider administering a dose every 4 hours or whenever blood loss exceeds 1000 mL.⁶² Engesæter and colleagues⁶³ found that antibiotic prophylaxis was most effective given 4 times perioperatively (1 time before surgery, 3 times after surgery). Postoperative antibiotics should not be administered longer than 24 hours, as prolonged dosing confers no benefit.⁵⁸ Operating room conditions must be optimized for prophylaxis. More people and operating room traffic in nonsterile corridors increase contamination of instruments open to air.⁶⁴ Laminar airflow systems are commonly used. Although there is little dispute that laminar flow decreases the bacterial load of air, there are mixed results regarding its benefit in preventing PJI.^65-68 Skin preparation may address patient risk factors. Hair clipping is preferred to shaving, which may cause microabrasions and increased susceptibility to skin flora.69 Patients should be prepared with antiseptic solution. One randomized controlled trial found that 2% chlorhexidine gluconate mixed with 70% isopropyl alcohol was superior to 10% povidone-iodine in preventing SSIs.⁷⁰ However, a recent cohort study showed a lower rate of superficial wound infections when 1% povidone-iodine (vs 0.5% chlorhexidine) was used with alcohol.⁷¹ This finding may indicate the need for alcohol preparation, higher concentrations of chlorhexidine, or both.

Proper scrubbing and protective gear are needed to reduce surgeon risk factors. Hand washing is a routine part of any surgery. Alcohol-based hand scrubs are as effective as hand scrubbing.65 They reduce local skin flora by 95% immediately and by 99% with repeated applications.⁷² Lidwell and colleagues⁷³ found a 75% reduction in infection when body exhaust suits were used in combination with laminar flow in a multicenter randomized controlled trial of 8052 patients. Sterile draping with impermeable drapes should be done over properly prepared skin. Ioban drapes (3M) are often used as a protective barrier. Interestingly, a Cochrane review found no benefit in using plastic adhesives impregnated with iodine over sterilely prepared skin.⁷⁴

 

 

Operative Considerations

Surgical gloves become contaminated in almost one third of cases, half the time during draping.⁷⁵ For this reason, many surgeons change gloves after draping. In addition, double gloving prevents a breech of aseptic technique should the outer glove become perforated.⁷⁶ Demircay and colleagues⁷⁷ assessed double latex gloving in arthroplasty and found the outer and inner gloves perforated in 18.4% and 8.4% of cases, respectively. Punctures are most common along the nondominant index finger, and then the dominant thumb.^77,78 Perforation is more common when 2 latex gloves are worn—vs 1 latex glove plus an outer cloth glove—and the chance of perforation increases with surgery duration. The inner glove may become punctured in up to 100% of operations that last over 3 hours.⁷⁹ Although Dodds and colleagues⁸⁰ found no change in bacterial counts on surgeons’ hands or gloves after perforation, precautions are still recommended. Al-Maiyah and colleagues⁸¹ went as far as to recommend glove changes at 20-minute intervals and before cementation.

Surgical instruments can be sources of contamination. Some authors change the suction tip every hour to minimize the risk of deep wound infection.^82-85 Others change it before femoral canal preparation and prosthesis insertion during THA.⁸⁶ The splash basin is frequently contaminated, and instruments placed in it should not be returned to the operative field.⁸⁷ Hargrove and colleagues⁸⁸ suggested pulsatile lavage decreases PJI more than bulb syringe irrigation does, whereas others argued that high-pressure lavage allows bacteria to penetrate more deeply, which could lead to retention of more bacteria.⁸⁹ Minimizing operating room time was found by Kurtz and colleagues⁹⁰ and Peersman and colleagues⁹¹ to decrease PJI incidence. Carroll and colleagues⁷¹ correlated longer tourniquet use with a higher rate of infection after TKA; proposed mechanisms include local tissue hypoxia and lowered concentrations of prophylactic antibiotics.

Similarly, minimizing blood loss and transfusion needs is another strategy for preventing infection. Allogenic transfusion may increase the risk of PJI 2 times.^23,71,92 The mechanism seems to be immune system modulation by allogenic blood, which impairs microcirculation and oxygen delivery at the surgical site.^23,75 Transfusions should be approached with caution, and consideration given to preoperative optimization and autologous blood donation. Cherian and colleagues⁹³ reviewed different blood management strategies and found preoperative iron therapy, intravenous erythropoietin, and autologous blood donation to be equally effective in reducing the need for allogenic transfusions. Numerous studies of tranexamic acid, thrombin-based hemostatic matrix (Floseal; Baxter Inc), and bipolar sealer with radiofrequency ablation (Aquamantys; Medtronic Inc) have found no alterations in infection rates, but most have used calculated blood loss, not PJI, as the primary endpoint.^94-105 Antibiotic cement also can be used to block infection.^63,106-110 Although liquid gentamicin may weaken bone cement,¹¹¹ most antibiotics, including powdered tobramycin and vancomycin, do not weaken its fatigue strength.^111-114 A recent meta-analysis by Parvizi and colleagues¹¹⁵ revealed that deep infection rates dropped from 2.3% to 1.2% with use of antibiotic cement for primary THAs. Cummins and colleagues,¹¹⁶ however, reported the limited cost-effectiveness of antibiotic cement in primary arthroplasty. Performing povidone-iodine lavage at the end of the case may be a more inexpensive alternative. Brown and colleagues¹¹⁷ found that rinsing with dilute povidone-iodine (.35%) for 3 minutes significantly decreased the incidence of PJI.

Closure techniques and sutures have been a focus of much of the recent literature. Winiarsky and colleagues³⁴ advocated using a longer incision for obese patients and augmenting closure in fattier areas with vertical mattress retention sutures, which are removed after 5 days. A barbed monofilament suture (Quill; Angiotech Inc) is gaining in popularity. Laboratory research has shown that bacteria adhere less to barbed monofilament sutures than to braided sutures.¹¹⁸ Smith and colleagues¹¹⁹ found a statistically nonsignificant higher rate of wound complications with barbed monofilament sutures, whereas Ting and colleagues120 found no difference in complications. These studies were powered to detect differences in time and cost, not postoperative complications. Skin adhesive (Dermabond; Ethicon Inc), also used in closure, may be superior to staples in avoiding superficial skin abscesses.¹²¹ Although expensive, silver-impregnated dressing has antimicrobial activity that reduces PJI incidence by up to 74%.¹²² One brand of this dressing (Aquacel; ConvaTec Inc) has a polyurethane waterproof barrier that allows it to be worn for 7 days.

 

 

Three factors commonly mentioned in PJI prevention show little supporting evidence. Drains, which are often used, may create a passage for postoperative infection and are associated with increased transfusion needs.^123,124 Adding antibiotics to irrigation solution¹²⁵ and routinely changing scalpel blades^126-129 also have little supporting evidence. In 2014, the utility of changing scalpel blades after incision was studied by Lee and colleagues,¹³⁰ who reported persistence of Propionibacterium acnes in the dermal layer after skin preparation. Their study, however, was isolated to the upper back region, not the hip or knee.

Postoperative Risk Prevention

Most arthroplasty patients receive anticoagulation after surgery, but it must be used with caution. Large hematomas can predispose to wound complications. Parvizi and colleagues¹³¹ associated wound drainage, hematoma, and subsequent PJI with an INR above 1.5 in the early postoperative period. Therefore, balanced anticoagulation is crucial. Postoperative glucose control is also essential, particularly for patients with diabetes. Although preoperative blood glucose levels may or may not affect PJI risk,^15,17,132 postoperative blood glucose levels of 126 mg/dL or higher are strongly associated with joint infections.¹³³ Even nondiabetic patients with postoperative morning levels over 140 mg/dL are 3 times more likely to develop an infection.¹⁷

Efforts should be made to discharge patients as soon as it is safe to do so. With longer hospital stays, patients are more exposed to nosocomial organisms and increased antibiotic resistance.^5,23,134 Outpatient antibiotics should be considered for dental, gastrointestinal, and genitourinary procedures. Oral antibiotic prophylaxis is controversial, as there is some evidence that dental procedures increase the risk of PJI only minimally.^10,135-138

Conclusion

PJI is a potentially devastating complication of TJA. For this reason, much research has been devoted to proper diagnosis and treatment. Although the literature on PJI prophylaxis is abundant, there is relatively little consensus on appropriate PJI precautions. Preoperative considerations should include medical comorbidities, use of immunocompromising medications, obesity, nutritional factors, smoking, alcohol use, and MRSA colonization. Surgeons must have a consistent intraoperative method of antibiotic administration, skin preparation, scrubbing, draping, gloving, instrument exchange, blood loss management, cementing, and closure. In addition, monitoring of postoperative anticoagulation and blood glucose management is important. Having a thorough understanding of PJI risk factors may help reduce the incidence of this devastating complication.

Nearly 2% of patients who undergo total knee arthroplasty (TKA) or total hip arthroplasty (THA) develop a periprosthetic joint infection (PJI) within 20 years of surgery, and 41% of these infections occur within the first 2 years.¹ PJI is the most common cause of TKA failure and the third leading complication of THA.² The estimated total hospital cost of treating PJI increased from $320 million in 2001 to $566 million in 2009, which can be extrapolated to $1.62 billion in 2020.³ By 2030, the projected increase in demand for TKA and THA will be 673% and 174% of what it was in 2005, respectively.⁴ Treatment of PJI of the knee is estimated to cost 3 to 4 times more than a primary TKA, and the cost of revision THA for PJI is almost $6000 more than that of revision TKA for PJI.³

In this article, we review the numerous preoperative, intraoperative, and postoperative methods of decreasing PJI incidence after total joint arthroplasty (TJA).

Preoperative Risk Prevention

Medical Comorbidities

Preoperative medical optimization is a key element in PJI prevention (Table 1). An American Society of Anesthesiologists classification score of 3 or more has been associated with doubled risk for surgical site infections (SSIs) after THA.5 Autoimmune conditions confer a particularly higher risk. In a retrospective double-cohort study of 924 subjects, Bongartz and colleagues⁶ found that, compared with osteoarthritis, rheumatoid arthritis tripled the risk of PJI. Small case series originally suggested a higher risk of PJI in patients with psoriasis,^7,8 but more recent studies have contradicted that finding.^9,10 Nevertheless, psoriatic plaques have elevated bacterial counts,¹¹ and planned incisions should circumvent these areas.

Diabetes mellitus is a clear risk factor for PJI.^12-16 Regarding whether preoperative glucose control affects risk, findings have been mixed. Mraovic and colleagues¹⁷ showed preoperative hyperglycemia to be an independent risk factor; Jämsen and colleagues,¹⁵ in a single-center analysis of more than 7000 TJAs, suggested preoperative blood glucose levels were not independently associated with PJI; and Iorio and colleagues¹⁶ found no association between surgical infections and hemoglobin A1c levels.

TJA incidence is higher in patients with chronic kidney disease (CKD) than in the general population.¹⁸ Dialysis users have a post-THA PJI rate as high as 13% to 19%.^19,20 Early clinical data suggested that outcomes are improved in dialysis users who undergo renal transplant, but this finding recently has been questioned.^19,21 Deegan and colleagues²² found an increased PJA rate of 3.5% even in low-level CKD (stage 1, 2, or 3), but this may be confounded by the increased association of CKD with other PJI-predisposing comorbidities.

Given a higher incidence of urinary tract infections (UTIs) among patients with PJI, some surgeons think UTIs predispose to PJIs by hematogenous seeding.^12,23,24 Symptomatic UTIs should be cleared before surgery and confirmed on urinalysis. Obstructive symptoms should prompt urologic evaluation. As asymptomatic pyuria and bacteriuria (colony counts, >1 × 105/mL) do not predispose to PJI, patients without symptoms do not require intervention.^25,26 Past history of malignancy may also have a role in PJI. In a case-control study of the Mayo Clinic arthroplasty experience from 1969 to 1991, Berbari and colleagues¹ found an association between malignancy and PJI (odds ratio, 2.4). They theorized the immunosuppressive effects of cancer treatment might be responsible for this increased risk.

 

 

Immunocompromising Medications

Immunocompromising medications are modifiable and should be adjusted before surgery. Stopping any disease-modifying antirheumatic drug (DMARD) more than 4 weeks before surgery is not recommended.²⁷

Corticosteroid use can lead to immunosuppression and increased protein catabolism, which impairs soft-tissue healing. To avoid flares or adrenal insufficiency, however, chronic corticosteroid users should continue their regular doses perioperatively.²⁸ On the day of surgery, they should also receive a stress dose of hydrocortisone 50 to 75 mg (for primary arthroplasty) or 100 to 150 mg (for revision arthroplasty), followed by expeditious tapering over 1 to 2 days.²⁹ DMARDs are increasingly used by rheumatologists. One of the most effective DMARDs is methotrexate. Despite its immunocompromising activity, methotrexate should be continued perioperatively, as stopping for even 2 days may increase flare-related complications.³⁰ Hydroxychloroquine can be continued perioperatively and has even been shown, by Johnson and Charnley,³¹ to prevent deep vein thromboses. Sulfasalazine can also be continued perioperatively—but with caution, as it may elevate international normalized ratio (INR) levels in patients receiving warfarin.²⁹ Most other DMARDs should be temporarily discontinued. Leflunomide and interleukin 1 antagonists, such as anakinra, should be stopped 1 to 2 days before surgery and restarted 10 to 14 days after surgery.²⁹ Rituximab should be stopped 1 week before surgery and restarted 10 to 14 days after surgery. Tumor necrosis factor α inhibitors should be discontinued for 2 half-lives before and after surgery.³² Etanercept has a half-life of 3 to 5 days; infliximab, 8 to 10 days; and adalimumab, 10 to 13 days. Most surgeons schedule surgery for the end of a dosing cycle and discontinue these biologic agents for another 10 to 14 days after surgery.

Metabolic Factors

Obese patients are susceptible to longer surgeries, more extensive dissection, poorly vascularized subcutaneous tissue, and higher requirements of weight-adjusted antibiotic dosing.¹³ Body mass index (BMI) of 40 kg/m² or more (morbid obesity) and BMI over 50 kg/m² have been associated with 9 times and 21.3 times increased risk of PJI, respectively.^13,14 Delaying surgery with dietary consultation has been suggested,^33,34 and bariatric surgery before TKA may decrease infection rates by 3.5 times.³⁵

Nutritional markers are considered before arthroplasty. According to most laboratories, a serum transferrin level under 200 mg/dL, albumin level under 3.5 g/dL, and total lymphocyte count under 1500 cells/mm³ indicate malnourishment, which can increase the incidence of wound complications by 5 to 7 times.³⁶ Patients should also have sufficient protein, vitamin, and mineral supplementation, particularly vitamins A and C, zinc, and copper.³⁷Smokers who cease smoking at least 4 to 6 weeks before surgery lower their wound complication rate by up to 26%.^38,39 When nicotine leaves the bloodstream, vasodilation occurs, oxygenation improves, and the immune system recovers.³⁹ Studies have found more SSIs in patients who abuse alcohol,40 and numerous authors have confirmed this finding in the arthroplasty population.^24,41,42 Alcohol inhibits platelet function and may predispose to a postoperative hematoma. In contrast to smoking cessation evidence, evidence regarding alcohol interventions in preventing postoperative infections is less conclusive.^43,44

MRSA Colonization

Methicillin-resistant Staphylococcus aureus (MRSA) is a particularly difficult bacterium to eradicate in PJI. As the mean cost of treating a single case of MRSA-related prosthetic infection is $107,264 vs $68,053 for susceptible strains,45,46 many infection-containment strategies focus on addressing benign MRSA colonization before surgery.

MRSA is present in the nares of 25 million people in the United States. Nasal colonization increases the risk of bacteremia 4-fold⁴⁷ and SSI 2- to 9-fold.^48,49 Nasal swabs are analyzed with either a rapid polymerase chain reaction (PCR) test, which provides results in 2 hours, or a bacterial culture, which provides results in 1 to 4 days. The PCR test is more expensive.

Eradication of MRSA colonization is increasingly prevalent. Several Scandinavian countries have instituted strict practices by which patients are denied elective surgery until negative nasal swabs are obtained.⁴⁹ Nasal decontamination is one method of colonization reduction. Topical mupirocin, which yields eradication in 91% of nasal carriers immediately after treatment and in 87% after 4 weeks,⁵⁰ is effective in reducing SSI rates only when used in conjunction with a body wash, which is used to clean the axilla and groin.⁵¹ There is no consensus on optimal timing, but Bode and colleagues⁵² found a significant decrease in deep SSIs when decontamination occurred just 24 hours before surgery.

 

 

Povidone-iodine showers went out of favor with the realization that chlorhexidine gluconate acts longer on the skin surface.^53,54 Preoperative showers involve rinsing with liquid chlorhexidine soap 24 to 48 hours before surgery. However, chlorhexidine binds preferentially to the cotton in washcloths instead of the skin. Edmiston and colleagues^54,55 found that 4% chlorhexidine liquid soaps achieve much lower skin chlorhexidine concentrations than 2% polyester cloths do. Use of these “chlorhexidine wipes” the night before and the day of surgery has decreased PJI after TKA from 2.2% to 0.6%.^56,57

Intraoperative Risk Prevention

Preparation

Which preoperative antibiotic to use is one of the first operative considerations in PJI prophylaxis (Table 2). Cefazolin is recommended as a first-line agent for its excellent soft-tissue penetration, long half-life, and activity against gram-positive bacteria such as skin flora.⁵⁸ Clindamycin may be considered for patients allergic to β-lactam antibiotics. Vancomycin may be considered for adjunctive use with cephalosporins in cases of known MRSA colonization. Vancomycin infusion should be started earlier than infusion with other antibiotics, as vancomycin must be infused slowly and takes longer to become therapeutic.

Antibiotic dosing should be based on local antibiograms, adjusted dosing weight, or BMI.⁵⁹ For revision arthroplasty, preoperative prophylaxis should not be stopped out of fear of affecting operative cultures.⁶⁰ Some surgeons pause antibiotic use if a preoperative joint aspirate has not been obtained. Infusion within 1 hour of incision is part of the pay-for-performance guidelines established by the US Centers for Medicare & Medicaid Services.⁶¹ An antibiotic should be redosed if the operation will take longer than 2 half-lives of the drug.⁵⁹ Surgeons should consider administering a dose every 4 hours or whenever blood loss exceeds 1000 mL.⁶² Engesæter and colleagues⁶³ found that antibiotic prophylaxis was most effective given 4 times perioperatively (1 time before surgery, 3 times after surgery). Postoperative antibiotics should not be administered longer than 24 hours, as prolonged dosing confers no benefit.⁵⁸ Operating room conditions must be optimized for prophylaxis. More people and operating room traffic in nonsterile corridors increase contamination of instruments open to air.⁶⁴ Laminar airflow systems are commonly used. Although there is little dispute that laminar flow decreases the bacterial load of air, there are mixed results regarding its benefit in preventing PJI.^65-68 Skin preparation may address patient risk factors. Hair clipping is preferred to shaving, which may cause microabrasions and increased susceptibility to skin flora.69 Patients should be prepared with antiseptic solution. One randomized controlled trial found that 2% chlorhexidine gluconate mixed with 70% isopropyl alcohol was superior to 10% povidone-iodine in preventing SSIs.⁷⁰ However, a recent cohort study showed a lower rate of superficial wound infections when 1% povidone-iodine (vs 0.5% chlorhexidine) was used with alcohol.⁷¹ This finding may indicate the need for alcohol preparation, higher concentrations of chlorhexidine, or both.

Proper scrubbing and protective gear are needed to reduce surgeon risk factors. Hand washing is a routine part of any surgery. Alcohol-based hand scrubs are as effective as hand scrubbing.65 They reduce local skin flora by 95% immediately and by 99% with repeated applications.⁷² Lidwell and colleagues⁷³ found a 75% reduction in infection when body exhaust suits were used in combination with laminar flow in a multicenter randomized controlled trial of 8052 patients. Sterile draping with impermeable drapes should be done over properly prepared skin. Ioban drapes (3M) are often used as a protective barrier. Interestingly, a Cochrane review found no benefit in using plastic adhesives impregnated with iodine over sterilely prepared skin.⁷⁴

 

 

Operative Considerations

Surgical gloves become contaminated in almost one third of cases, half the time during draping.⁷⁵ For this reason, many surgeons change gloves after draping. In addition, double gloving prevents a breech of aseptic technique should the outer glove become perforated.⁷⁶ Demircay and colleagues⁷⁷ assessed double latex gloving in arthroplasty and found the outer and inner gloves perforated in 18.4% and 8.4% of cases, respectively. Punctures are most common along the nondominant index finger, and then the dominant thumb.^77,78 Perforation is more common when 2 latex gloves are worn—vs 1 latex glove plus an outer cloth glove—and the chance of perforation increases with surgery duration. The inner glove may become punctured in up to 100% of operations that last over 3 hours.⁷⁹ Although Dodds and colleagues⁸⁰ found no change in bacterial counts on surgeons’ hands or gloves after perforation, precautions are still recommended. Al-Maiyah and colleagues⁸¹ went as far as to recommend glove changes at 20-minute intervals and before cementation.

Surgical instruments can be sources of contamination. Some authors change the suction tip every hour to minimize the risk of deep wound infection.^82-85 Others change it before femoral canal preparation and prosthesis insertion during THA.⁸⁶ The splash basin is frequently contaminated, and instruments placed in it should not be returned to the operative field.⁸⁷ Hargrove and colleagues⁸⁸ suggested pulsatile lavage decreases PJI more than bulb syringe irrigation does, whereas others argued that high-pressure lavage allows bacteria to penetrate more deeply, which could lead to retention of more bacteria.⁸⁹ Minimizing operating room time was found by Kurtz and colleagues⁹⁰ and Peersman and colleagues⁹¹ to decrease PJI incidence. Carroll and colleagues⁷¹ correlated longer tourniquet use with a higher rate of infection after TKA; proposed mechanisms include local tissue hypoxia and lowered concentrations of prophylactic antibiotics.

Similarly, minimizing blood loss and transfusion needs is another strategy for preventing infection. Allogenic transfusion may increase the risk of PJI 2 times.^23,71,92 The mechanism seems to be immune system modulation by allogenic blood, which impairs microcirculation and oxygen delivery at the surgical site.^23,75 Transfusions should be approached with caution, and consideration given to preoperative optimization and autologous blood donation. Cherian and colleagues⁹³ reviewed different blood management strategies and found preoperative iron therapy, intravenous erythropoietin, and autologous blood donation to be equally effective in reducing the need for allogenic transfusions. Numerous studies of tranexamic acid, thrombin-based hemostatic matrix (Floseal; Baxter Inc), and bipolar sealer with radiofrequency ablation (Aquamantys; Medtronic Inc) have found no alterations in infection rates, but most have used calculated blood loss, not PJI, as the primary endpoint.^94-105 Antibiotic cement also can be used to block infection.^63,106-110 Although liquid gentamicin may weaken bone cement,¹¹¹ most antibiotics, including powdered tobramycin and vancomycin, do not weaken its fatigue strength.^111-114 A recent meta-analysis by Parvizi and colleagues¹¹⁵ revealed that deep infection rates dropped from 2.3% to 1.2% with use of antibiotic cement for primary THAs. Cummins and colleagues,¹¹⁶ however, reported the limited cost-effectiveness of antibiotic cement in primary arthroplasty. Performing povidone-iodine lavage at the end of the case may be a more inexpensive alternative. Brown and colleagues¹¹⁷ found that rinsing with dilute povidone-iodine (.35%) for 3 minutes significantly decreased the incidence of PJI.

Closure techniques and sutures have been a focus of much of the recent literature. Winiarsky and colleagues³⁴ advocated using a longer incision for obese patients and augmenting closure in fattier areas with vertical mattress retention sutures, which are removed after 5 days. A barbed monofilament suture (Quill; Angiotech Inc) is gaining in popularity. Laboratory research has shown that bacteria adhere less to barbed monofilament sutures than to braided sutures.¹¹⁸ Smith and colleagues¹¹⁹ found a statistically nonsignificant higher rate of wound complications with barbed monofilament sutures, whereas Ting and colleagues120 found no difference in complications. These studies were powered to detect differences in time and cost, not postoperative complications. Skin adhesive (Dermabond; Ethicon Inc), also used in closure, may be superior to staples in avoiding superficial skin abscesses.¹²¹ Although expensive, silver-impregnated dressing has antimicrobial activity that reduces PJI incidence by up to 74%.¹²² One brand of this dressing (Aquacel; ConvaTec Inc) has a polyurethane waterproof barrier that allows it to be worn for 7 days.

 

 

Three factors commonly mentioned in PJI prevention show little supporting evidence. Drains, which are often used, may create a passage for postoperative infection and are associated with increased transfusion needs.^123,124 Adding antibiotics to irrigation solution¹²⁵ and routinely changing scalpel blades^126-129 also have little supporting evidence. In 2014, the utility of changing scalpel blades after incision was studied by Lee and colleagues,¹³⁰ who reported persistence of Propionibacterium acnes in the dermal layer after skin preparation. Their study, however, was isolated to the upper back region, not the hip or knee.

Postoperative Risk Prevention

Most arthroplasty patients receive anticoagulation after surgery, but it must be used with caution. Large hematomas can predispose to wound complications. Parvizi and colleagues¹³¹ associated wound drainage, hematoma, and subsequent PJI with an INR above 1.5 in the early postoperative period. Therefore, balanced anticoagulation is crucial. Postoperative glucose control is also essential, particularly for patients with diabetes. Although preoperative blood glucose levels may or may not affect PJI risk,^15,17,132 postoperative blood glucose levels of 126 mg/dL or higher are strongly associated with joint infections.¹³³ Even nondiabetic patients with postoperative morning levels over 140 mg/dL are 3 times more likely to develop an infection.¹⁷

Efforts should be made to discharge patients as soon as it is safe to do so. With longer hospital stays, patients are more exposed to nosocomial organisms and increased antibiotic resistance.^5,23,134 Outpatient antibiotics should be considered for dental, gastrointestinal, and genitourinary procedures. Oral antibiotic prophylaxis is controversial, as there is some evidence that dental procedures increase the risk of PJI only minimally.^10,135-138

Conclusion

PJI is a potentially devastating complication of TJA. For this reason, much research has been devoted to proper diagnosis and treatment. Although the literature on PJI prophylaxis is abundant, there is relatively little consensus on appropriate PJI precautions. Preoperative considerations should include medical comorbidities, use of immunocompromising medications, obesity, nutritional factors, smoking, alcohol use, and MRSA colonization. Surgeons must have a consistent intraoperative method of antibiotic administration, skin preparation, scrubbing, draping, gloving, instrument exchange, blood loss management, cementing, and closure. In addition, monitoring of postoperative anticoagulation and blood glucose management is important. Having a thorough understanding of PJI risk factors may help reduce the incidence of this devastating complication.

Although total shoulder arthroplasty (TSA) has proved to be a reliable solution in older patients, treatment in younger patients with glenohumeral arthritis remains controversial, and there are still few reliable long-term surgical options.^1-8 These options include abrasion arthroplasty and arthroscopic management,^9,10 biologic glenoid resurfacing,^11,12 and humeral hemiarthroplasty with¹³ or without^14,15 glenoid treatment and anatomical TSA.

In the younger cohort, 20-year TSA survivorship rates up to 84% have been reported, and unsatisfactory subjective outcomes have been unacceptably high.¹⁶ In addition, there is a paucity of literature addressing the impact of TSA on return to sport. Recommendations on returning to an athletic life style are based largely on surveys of expert opinion^17,18 and heterogeneous studies of either older patients (eg, age >50-55 years) who are active^19-21 or younger patients with no defined level of activity.^{5,7,8,16,22-24}

To our knowledge, no one has evaluated the short-term morbidity and clinical outcomes within a young, high-demand patient population, such as the US military. Therefore, we conducted a study to evaluate the clinical success and complications of TSA performed for glenohumeral arthritis in a young, active population. We hypothesized that patients who had undergone TSA would have a low rate of return to duty, an increased rate of component failure, and a higher reoperation rate because of increased upper extremity demands.

Materials and Methods

After obtaining protocol approval from the William Beaumont Army Medical Center Institutional Review Board, we searched the Military Health System (MHS) Management Analysis and Reporting Tool (M2) database to retrospectively review the cases of all tri-service US military service members who had undergone primary anatomical TSA (Current Procedural Terminology code 23472) between January 1, 2007 and June 31, 2014. This was a multisurgeon, multicenter study. Patient exclusion criteria were nonmilitary or retired status at time of surgery; primary surgery consisting of limited glenohumeral resurfacing procedure, hemiarthroplasty, or reverse TSA; surgery for acute proximal humerus fracture; rotator cuff deficiency diagnosed before or during surgery; and insufficient follow-up (eg, <12 months, unless medically separated beforehand).

The M2 database is an established tool that has been used for clinical outcomes research on treatment of a variety of orthopedic conditions.25,26 The Medical Data Repository, which is operated by MHS, is populated by its military healthcare providers. The MHS, which offers worldwide coverage for all beneficiaries either at Department of Defense facilities or purchased using civilian providers, is among the largest known closed healthcare systems.

All active-duty US military service members are uniformly required to adhere to stringent and regularly evaluated physical fitness standards, which typically exceed those of average civilians. Routine physical training is required in the form of aerobic fitness, weight training, tactical field exercises, and core military tasks, such as the ability to march at least 2 miles while carrying heavy fighting loads. In addition to satisfying required height and weight standards, all service members are subject to semiannual service-specific physical fitness evaluations inclusive of timed push-ups, sit-ups, and an aerobic event. Service members may also be required to maintain a level of physical training above these baseline standards, contingent on their branch of service, rank, and military occupational specialty. If a service member is unable to maintain these standards, medical separation may be initiated.

Demographic and occupational data were extracted from the database. These data included age, sex, military rank, and branch of service. Line-by-line analysis of the Armed Forces Health Longitudinal Technology Application (Version 22; 3M) electronic medical record was then performed to confirm the underlying diagnosis, surgical procedure, and surgery date. Further chart review yielded additional patient-based factors (eg, laterality, hand dominance, presence and type of prior shoulder surgeries) and surgical factors (eg, surgery indication, implant design). We evaluated clinical and functional outcomes as well as perioperative complications, including both major and minor systemic and local complications as previously described^27,28; preoperative and postoperative range of motion (ROM) and self-reported pain score (SRPS, scale 1-10) as measured by physical therapist and surgeon at follow-up; secondary surgical interventions; timing of return to duty; and postoperative deployment history. The primary outcome measures were revision reoperation after index procedure, and military discharge for persistent shoulder-related disability. Clinical failure was defined as component failure or reoperation. Medical Evaluation Board (MEB) is a formal separation from the military in which it is deemed that a service member is no longer able to fulfill his or her duty because of a medical condition.

 

Statistical Analysis

Continuous variables were compared using statistical means with 95% confidence intervals (CIs) and/or SDs. Categorical data were reported as frequencies or percentages. Univariate analysis was performed to assess the correlation between possible risk factors and the primary outcome measures. P < .05 was considered statistically significant.

Results

Demographics

We identified 24 service members (26 shoulders) who had undergone anatomical TSA during the study period (Table 1). Mean (SD) age was 45.8 (4.5) years (range, 35-54 years), and the cohort was predominately male (25/26 shoulders; 96.2%). Most cohort members were of senior enlisted rank (14, 58.3%), and the US Army was the predominant branch of military service (13, 54.2%). The right side was the operative extremity in 7 cases (26.9%), and the dominant shoulder was involved in 6 cases (23.1%). Two patients (8.3%) underwent staged bilateral TSA. Most patients (76.9%) underwent TSA on the nondominant extremity.

Surgical Variables

TSA was indicated for post-instability arthropathy in 13 cases (50.0%), posttraumatic osteoarthritis in 7 cases (26.9%), and unspecified glenohumeral arthritis, which includes primary glenohumeral osteoarthritis, in 5 cases (19.2%) (Table 2). One case was attributed to iatrogenically induced chondrolysis secondary to intra-articular lidocaine pump. Twelve patients (46.2%) had at least 1 previous surgery. Of the shoulders with instability, 10 (76.9%) had undergone a total of 14 surgical stabilization procedures—10 anterior labral repairs, 2 posterior labral repairs, and 2 capsular plications. The other shoulders had undergone a total of 18 procedures, which included 4 rotator cuff repairs and 3 cartilage restoration procedures.

Clinical Outcomes

Mean (SD) follow-up was 41.0 (21.3) months (range, 11.6-97.6 months). All but 1 shoulder (96.2%) had follow-up of 12 months or more (the only patient with shorter follow-up was because of MEB), and 76.9% of patients had follow-up of 24 months or more (4 of the 6 patients with follow-up under 24 months were medically separated) (Table 3). In all cases, mean ROM improved with respect to flexion, abduction, and external rotation. At final follow-up, mean (SD) ROM was 138° (36°) forward flexion (range, 60°-180°), 125° (39°) abduction (range, 45°-180°), 48° (19°) external rotation at 0° abduction (range, 20°-90°), and 80° (9.4°) external rotation at 90° abduction (range, 70°-90°). Preoperative flexion, abduction, and external rotation at 0° and 90° abduction were all improved at final follow-up. The most improvement in ROM occurred within 6 months after surgery.

Overall patient satisfaction with surgery was 92.3% (n = 24). Ultimately, 18 (72.0%) of 25 shoulders with follow-up of 1 year or more were able to return to active duty within 1 year after surgery, though only 10 (45.5%) of 22 with follow-up of 2 years or more remained active 2 years after surgery. Furthermore, 5 patients (20.8%) were deployed after surgery, and all were still on active duty at final follow-up. By final follow-up, 9 (37.5%) of 24 service members were unable to return to military function; 7 had been medically discharged from the military for persistent shoulder disability, and 2 were in the process of being medically discharged.

In all cases, SRPS improved from before surgery (5.2 out of 10) to final follow-up (1.4). At final follow-up, 22 patients (88.0%) reported mild pain (0-3), and no one had pain above 6.

 

Complications

Nine patients had a total of 12 postoperative complications (46.2%): 6 component failures (23.1%), 2 neurologic injuries (7.7%; 1 permanent axillary nerve injury, 1 transient brachial plexus neuritis), 2 cases of adhesive capsulitis (7.7%), and 2 episodes of venous thrombosis (7.7%; 1 superficial, 1 deep) (Table 4). There were no documented infections. Six reoperations (23.1%) were performed for the 6 component failures (2 traumatic dislocations of prosthesis resulting in acute glenoid component failure, 3 cases of atraumatic glenoid loosening, 1 case of humeral stem loosening after periprosthetic fracture). Atraumatic glenoid component loosening occurred a mean (SD) of 40.6 (14.2) months after surgery (range, 20.8-54.2 months).

Surgical Failures

Eight service members underwent MEB. Six patients experienced component failure. Factors contributing to both clinical failure and separation from active duty by means of MEB were evaluated with univariate analysis (Table 5). No statistically significant risk factors, including surgical revision and presence of perioperative complications, were identified.

Discussion

We confirmed that our cohort of young service members (mean age, 45.8 years), who had undergone TSA for glenohumeral arthritis, had a relatively higher rate of component failure (23.1%) and a higher reoperation rate (23.1%) with low rates of return to military duty at short-term to midterm follow-up. Our results parallel those of a limited series with a younger cohort (Table 6).^{7,16,19,21,23,24} The high demand and increased life expectancy of the younger patients with glenohumeral arthritis potentiates the risk of complications, component loosening, and ultimate failure.²⁹ To our knowledge, the present article is the first to report clinical and functional outcomes and perioperative risk profiles in a homogenously young, active military cohort after TSA.

 

The mean age of our study population (46 years) is one of the lowest in the literature. TSA in younger patients (age, <50-55 years) and older, active patients (>55 years) has received increased attention as a result of the expanding indications and growing popularity of TSA in these groups. Other studies have upheld the efficacy of TSA in achieving predictable pain relief and functional improvement in a diverse and predominantly elderly population.^15,30-34 Alternative treatments, including humeral head resurfacing^15,30,35 and soft-tissue interposition,^15,36-40 have also shown inferior short- and long-term results in terms of longevity and degree of clinical or functional improvement.^31-34,41 In addition, the ream-and-run technique has had promising early results by improving glenohumeral kinematics, pain relief, and shoulder function.^13,42,43 However, although implantation of a glenoid component is avoided in young, active people because of reduced longevity and higher rates of component failure, the trade-offs are inadequately treated glenoid disease, suboptimal pain relief, and progression of glenoid arthritis eventually requiring revision. Furthermore, midterm and long-term survivorship of TSA in general is unknown, and there remain few good options for treating end-stage arthritis in young, active patients.

Our cohort had high rates of complications (46.2%) and revisions (23.1%). Two in 5 patients had postoperative complications, most commonly component failure resulting in reoperation. In the literature, complication rates among young patients who underwent TSA are much lower (4.8%-10.9%).^16,23,24 Our cohort’s most common complication was component failure (23.1%), which was most often attributed to atraumatic, aseptic glenoid component loosening and required reoperation. Previously reported revision rates in a young population that underwent TSA (0%-11%)^16,23,24 were also significantly lower than those in the present analysis (23.1%), underscoring the impact of operative indications, postoperative activity levels, and occupational demands on ultimate failure rates. Interestingly, all revisions in our study were for component failure, whereas previous reports have described a higher rate for infection.²² However, the same studies also found glenoid lucency rates as high as 76% at 10-year follow-up.¹⁶ Furthermore, in a review of 136 TSAs with unsatisfactory outcomes, glenoid loosening was the most common reason for presenting to clinic after surgery.⁴⁴ Specifically, our population had a high rate of glenohumeral arthritis secondary to instability (50.0%) and posttraumatic osteoarthritis (26.9%). For many reasons, outcomes were worse in younger patients with a history of glenohumeral instability³³ than in older patients without a high incidence of instability.⁴⁵ This young cohort with higher demands may have had accelerated polyethylene wear patterns caused by repetitive overhead activity, which may have arisen because of a higher functional profile after surgery and greater patient expectations after arthroplasty. In addition, patients with a history of instability may have altered glenohumeral anatomy, especially with previous arthroscopic or open stabilization procedures. Anatomical changes include excessive posterior glenoid wear, internal rotation contracture, patulous capsular tissue, static or dynamic posterior humeral subluxation, and possible overconstraint after prior stabilization procedures. Almost half of our population had a previous surgery; our patients averaged 1.7 previous surgeries each.

Although estimates of component survivorship at a high-volume civilian tertiary-referral center were as high as 97% at 10 years and 84% at 20 years,^7,16 10-year survivorship in patients with a history of instability was only 61%.3 TSA survivorship in our young, active cohort is already foreseeably dramatically reduced, given the 23.1% revision rate at 28.5-month follow-up. This consideration must be addressed during preoperative counseling with the young patient with glenohumeral arthritis and a history of shoulder instability.

 

Despite the high rates of complications and revisions in our study, 92.3% of patients were satisfied with surgery, 88.0% experienced minimal persistence of pain (mean 3.8-point decrease on SRPS), and 100% maintained improved ROM at final follow-up. Satisfaction in the young population has varied significantly, from 52% to 95%, generally on the basis of physical activity.^16,22-24 The reasonable rate of postoperative satisfaction in the present analysis is comparable to what has been reported in patients of a similar age (Table 6).^7,16,22 However, despite high satisfaction and pain relief, patients were inconsistently able to return to the upper limits of physical activity required of active-duty military service. In addition, we cannot exclude secondary gain motivations for pursuing medical retirement, similar to that seen in patients receiving worker’s compensation.

Other authors have conversely found more favorable functional outcomes and survivorship rates.^23,24 In a retrospective review of 46 TSAs in patients 55 years or younger, Bartelt and colleagues²⁴ found sustained improvements in pain, ROM, and satisfaction at 7-year follow-up.24 Raiss and colleagues²³ conducted a prospective study of TSA outcomes in 21 patients with a mean age of 55 years and a mean follow-up of 7 years and reported no revisions and only 1 minor complication, a transient brachial plexus palsy.²³ The discrepancy between these studies may reflect different activity levels and underlying pathology between cohorts. The present population is unique in that it represents a particularly difficult confluence of factors for shoulder arthroplasty surgeons. The high activity, significant overhead and lifting occupational demands, and discordant patient expectations of this military cohort place a significant functional burden on the implants, the glenoid component in particular. Furthermore, this patient group has a higher incidence of more complex glenohumeral pathology resulting in instability, posttraumatic, or capsulorrhaphy arthropathy, and multiple prior arthroscopic and open stabilization procedures.

At final follow-up, only 33% of our patients were still on activity duty, 37.5% had completed or were completing medical separation from the military after surgery for persistent shoulder disability, and 37.5% were retired from the military. Five patients (20.8%) deployed after surgery. This young, active cohort of service members who had TSA for glenohumeral arthritis faced a unique set of tremendous physical demands. A retrospective case series investigated return to sport in 100 consecutive patients (mean age, 68.9 years) who were participating in recreational and competitive athletics and underwent unilateral TSA.²¹ The patients were engaged most commonly in swimming (20.4%), golf (16.3%), cycling (16.3%), and fitness training (16.3%). The authors found that, at a mean follow-up of 2.8 years, 49 patients (89%) were able to continue in sports, though 36.7% thought their sport activity was restricted after TSA. In another retrospective case series (61 TSAs), McCarty and colleagues¹⁹ found that 48 patients (71%) were improved in their sports participation, and 50% increased their frequency of participation after surgery.

There are no specific recommendations on returning to military service or high-level sport after surgery. Recommendations on returning to sport after TSA have been based largely on small case series involving specific sports^46,47 and surveys of expert opinion.^17,18 In a survey on postoperative physical activity in young patients after TSA conducted by Healy and colleagues,¹⁷ 35 American Shoulder and Elbow Surgeons members recommended avoiding contact and impact sports while permitting return to nonimpact sports, such as swimming, which may still impart significant stress to the glenohumeral joint. In an international survey of 101 shoulder and elbow surgeons, Magnussen and colleagues¹⁸ also found that most recommended avoiding a return to impact sports that require intensive upper extremity demands and permitting full return to sports at preoperative levels. This likely is a result of the perception that most of these patients having TSA are older and have less rigorous involvement in sports at the outset and a lower propensity for adverse patient outcomes. However, these recommendations may place a younger, more high-demand patient at significantly greater risk. The active-duty cohort engages in daily physical training, including push-ups and frequent overhead lifting, which could account for the high failure rates and low incidence of postoperative deployment. Although TSA seems to demonstrate good initial results in terms of return to high-demand activities, the return-to-duty profile in our study highlights the potential pitfalls of TSA in active individuals attempting to return to high-demand preoperative function.

 

Our analysis was limited by the fact that we used a small patient cohort, contributing to underpowered analysis of the potential risk factors predictive of reoperation and medical discharge. Although our minimum follow-up was 12 months, with the exception of 1 patient who was medically separated at 11.6 months because of shoulder disability, we captured 5 patients (19.2%) who underwent medical separation but who would otherwise be excluded. Therefore, this limitation is not major in that, with a longer minimum follow-up, we would be excluding a significant number of patients with such persistent disability after TSA that they would not be able to return to duty at anywhere near their previous level. In this retrospective study, we were additionally limited to analysis of the data in the medical records and could not control for variables such as surgeon technique, implant choice, and experience. Complete radiographic images were not available, limiting analysis of radiographic outcomes. Given the lack of a standardized preoperative imaging protocol, we could not evaluate glenoid version on axial imaging. It is possible that some patients with early aseptic glenoid loosening had posterior subluxation or a Walch B2 glenoid, which has a higher failure rate.⁴⁸ The strengths of this study include its unique analysis of a homogeneous young, active, high-risk patient cohort within a closed healthcare system. In the military, these patients are subject to intense daily physical and occupational demands. In addition, the clinical and functional outcomes we studied are patient-centered and therefore relevant during preoperative counseling. Further investigations might focus on validated outcome measures and on midterm to long-term TSA outcomes in an active military population vis-à-vis other alternatives for clinical management.

Conclusion

By a mean follow-up of 3.5 years, only a third of the service members had returned to active duty, roughly a third had retired, and more than a third had been medically discharged because of persistent disability attributable to the shoulder. Despite initial improvements in ROM and pain, midterm outcomes were poor. The short-term complication rate (46.2%) and the rate of reoperation for component failure (23.1%) should be emphasized during preoperative counseling.

Although total shoulder arthroplasty (TSA) has proved to be a reliable solution in older patients, treatment in younger patients with glenohumeral arthritis remains controversial, and there are still few reliable long-term surgical options.^1-8 These options include abrasion arthroplasty and arthroscopic management,^9,10 biologic glenoid resurfacing,^11,12 and humeral hemiarthroplasty with¹³ or without^14,15 glenoid treatment and anatomical TSA.

In the younger cohort, 20-year TSA survivorship rates up to 84% have been reported, and unsatisfactory subjective outcomes have been unacceptably high.¹⁶ In addition, there is a paucity of literature addressing the impact of TSA on return to sport. Recommendations on returning to an athletic life style are based largely on surveys of expert opinion^17,18 and heterogeneous studies of either older patients (eg, age >50-55 years) who are active^19-21 or younger patients with no defined level of activity.^{5,7,8,16,22-24}

To our knowledge, no one has evaluated the short-term morbidity and clinical outcomes within a young, high-demand patient population, such as the US military. Therefore, we conducted a study to evaluate the clinical success and complications of TSA performed for glenohumeral arthritis in a young, active population. We hypothesized that patients who had undergone TSA would have a low rate of return to duty, an increased rate of component failure, and a higher reoperation rate because of increased upper extremity demands.

Materials and Methods

After obtaining protocol approval from the William Beaumont Army Medical Center Institutional Review Board, we searched the Military Health System (MHS) Management Analysis and Reporting Tool (M2) database to retrospectively review the cases of all tri-service US military service members who had undergone primary anatomical TSA (Current Procedural Terminology code 23472) between January 1, 2007 and June 31, 2014. This was a multisurgeon, multicenter study. Patient exclusion criteria were nonmilitary or retired status at time of surgery; primary surgery consisting of limited glenohumeral resurfacing procedure, hemiarthroplasty, or reverse TSA; surgery for acute proximal humerus fracture; rotator cuff deficiency diagnosed before or during surgery; and insufficient follow-up (eg, <12 months, unless medically separated beforehand).

The M2 database is an established tool that has been used for clinical outcomes research on treatment of a variety of orthopedic conditions.25,26 The Medical Data Repository, which is operated by MHS, is populated by its military healthcare providers. The MHS, which offers worldwide coverage for all beneficiaries either at Department of Defense facilities or purchased using civilian providers, is among the largest known closed healthcare systems.

All active-duty US military service members are uniformly required to adhere to stringent and regularly evaluated physical fitness standards, which typically exceed those of average civilians. Routine physical training is required in the form of aerobic fitness, weight training, tactical field exercises, and core military tasks, such as the ability to march at least 2 miles while carrying heavy fighting loads. In addition to satisfying required height and weight standards, all service members are subject to semiannual service-specific physical fitness evaluations inclusive of timed push-ups, sit-ups, and an aerobic event. Service members may also be required to maintain a level of physical training above these baseline standards, contingent on their branch of service, rank, and military occupational specialty. If a service member is unable to maintain these standards, medical separation may be initiated.

Demographic and occupational data were extracted from the database. These data included age, sex, military rank, and branch of service. Line-by-line analysis of the Armed Forces Health Longitudinal Technology Application (Version 22; 3M) electronic medical record was then performed to confirm the underlying diagnosis, surgical procedure, and surgery date. Further chart review yielded additional patient-based factors (eg, laterality, hand dominance, presence and type of prior shoulder surgeries) and surgical factors (eg, surgery indication, implant design). We evaluated clinical and functional outcomes as well as perioperative complications, including both major and minor systemic and local complications as previously described^27,28; preoperative and postoperative range of motion (ROM) and self-reported pain score (SRPS, scale 1-10) as measured by physical therapist and surgeon at follow-up; secondary surgical interventions; timing of return to duty; and postoperative deployment history. The primary outcome measures were revision reoperation after index procedure, and military discharge for persistent shoulder-related disability. Clinical failure was defined as component failure or reoperation. Medical Evaluation Board (MEB) is a formal separation from the military in which it is deemed that a service member is no longer able to fulfill his or her duty because of a medical condition.

 

Statistical Analysis

Continuous variables were compared using statistical means with 95% confidence intervals (CIs) and/or SDs. Categorical data were reported as frequencies or percentages. Univariate analysis was performed to assess the correlation between possible risk factors and the primary outcome measures. P < .05 was considered statistically significant.

Results

Demographics

We identified 24 service members (26 shoulders) who had undergone anatomical TSA during the study period (Table 1). Mean (SD) age was 45.8 (4.5) years (range, 35-54 years), and the cohort was predominately male (25/26 shoulders; 96.2%). Most cohort members were of senior enlisted rank (14, 58.3%), and the US Army was the predominant branch of military service (13, 54.2%). The right side was the operative extremity in 7 cases (26.9%), and the dominant shoulder was involved in 6 cases (23.1%). Two patients (8.3%) underwent staged bilateral TSA. Most patients (76.9%) underwent TSA on the nondominant extremity.

Surgical Variables

TSA was indicated for post-instability arthropathy in 13 cases (50.0%), posttraumatic osteoarthritis in 7 cases (26.9%), and unspecified glenohumeral arthritis, which includes primary glenohumeral osteoarthritis, in 5 cases (19.2%) (Table 2). One case was attributed to iatrogenically induced chondrolysis secondary to intra-articular lidocaine pump. Twelve patients (46.2%) had at least 1 previous surgery. Of the shoulders with instability, 10 (76.9%) had undergone a total of 14 surgical stabilization procedures—10 anterior labral repairs, 2 posterior labral repairs, and 2 capsular plications. The other shoulders had undergone a total of 18 procedures, which included 4 rotator cuff repairs and 3 cartilage restoration procedures.

Clinical Outcomes

Mean (SD) follow-up was 41.0 (21.3) months (range, 11.6-97.6 months). All but 1 shoulder (96.2%) had follow-up of 12 months or more (the only patient with shorter follow-up was because of MEB), and 76.9% of patients had follow-up of 24 months or more (4 of the 6 patients with follow-up under 24 months were medically separated) (Table 3). In all cases, mean ROM improved with respect to flexion, abduction, and external rotation. At final follow-up, mean (SD) ROM was 138° (36°) forward flexion (range, 60°-180°), 125° (39°) abduction (range, 45°-180°), 48° (19°) external rotation at 0° abduction (range, 20°-90°), and 80° (9.4°) external rotation at 90° abduction (range, 70°-90°). Preoperative flexion, abduction, and external rotation at 0° and 90° abduction were all improved at final follow-up. The most improvement in ROM occurred within 6 months after surgery.

Overall patient satisfaction with surgery was 92.3% (n = 24). Ultimately, 18 (72.0%) of 25 shoulders with follow-up of 1 year or more were able to return to active duty within 1 year after surgery, though only 10 (45.5%) of 22 with follow-up of 2 years or more remained active 2 years after surgery. Furthermore, 5 patients (20.8%) were deployed after surgery, and all were still on active duty at final follow-up. By final follow-up, 9 (37.5%) of 24 service members were unable to return to military function; 7 had been medically discharged from the military for persistent shoulder disability, and 2 were in the process of being medically discharged.

In all cases, SRPS improved from before surgery (5.2 out of 10) to final follow-up (1.4). At final follow-up, 22 patients (88.0%) reported mild pain (0-3), and no one had pain above 6.

 

Complications

Nine patients had a total of 12 postoperative complications (46.2%): 6 component failures (23.1%), 2 neurologic injuries (7.7%; 1 permanent axillary nerve injury, 1 transient brachial plexus neuritis), 2 cases of adhesive capsulitis (7.7%), and 2 episodes of venous thrombosis (7.7%; 1 superficial, 1 deep) (Table 4). There were no documented infections. Six reoperations (23.1%) were performed for the 6 component failures (2 traumatic dislocations of prosthesis resulting in acute glenoid component failure, 3 cases of atraumatic glenoid loosening, 1 case of humeral stem loosening after periprosthetic fracture). Atraumatic glenoid component loosening occurred a mean (SD) of 40.6 (14.2) months after surgery (range, 20.8-54.2 months).

Surgical Failures

Eight service members underwent MEB. Six patients experienced component failure. Factors contributing to both clinical failure and separation from active duty by means of MEB were evaluated with univariate analysis (Table 5). No statistically significant risk factors, including surgical revision and presence of perioperative complications, were identified.

Discussion

We confirmed that our cohort of young service members (mean age, 45.8 years), who had undergone TSA for glenohumeral arthritis, had a relatively higher rate of component failure (23.1%) and a higher reoperation rate (23.1%) with low rates of return to military duty at short-term to midterm follow-up. Our results parallel those of a limited series with a younger cohort (Table 6).^{7,16,19,21,23,24} The high demand and increased life expectancy of the younger patients with glenohumeral arthritis potentiates the risk of complications, component loosening, and ultimate failure.²⁹ To our knowledge, the present article is the first to report clinical and functional outcomes and perioperative risk profiles in a homogenously young, active military cohort after TSA.

 

The mean age of our study population (46 years) is one of the lowest in the literature. TSA in younger patients (age, <50-55 years) and older, active patients (>55 years) has received increased attention as a result of the expanding indications and growing popularity of TSA in these groups. Other studies have upheld the efficacy of TSA in achieving predictable pain relief and functional improvement in a diverse and predominantly elderly population.^15,30-34 Alternative treatments, including humeral head resurfacing^15,30,35 and soft-tissue interposition,^15,36-40 have also shown inferior short- and long-term results in terms of longevity and degree of clinical or functional improvement.^31-34,41 In addition, the ream-and-run technique has had promising early results by improving glenohumeral kinematics, pain relief, and shoulder function.^13,42,43 However, although implantation of a glenoid component is avoided in young, active people because of reduced longevity and higher rates of component failure, the trade-offs are inadequately treated glenoid disease, suboptimal pain relief, and progression of glenoid arthritis eventually requiring revision. Furthermore, midterm and long-term survivorship of TSA in general is unknown, and there remain few good options for treating end-stage arthritis in young, active patients.

Our cohort had high rates of complications (46.2%) and revisions (23.1%). Two in 5 patients had postoperative complications, most commonly component failure resulting in reoperation. In the literature, complication rates among young patients who underwent TSA are much lower (4.8%-10.9%).^16,23,24 Our cohort’s most common complication was component failure (23.1%), which was most often attributed to atraumatic, aseptic glenoid component loosening and required reoperation. Previously reported revision rates in a young population that underwent TSA (0%-11%)^16,23,24 were also significantly lower than those in the present analysis (23.1%), underscoring the impact of operative indications, postoperative activity levels, and occupational demands on ultimate failure rates. Interestingly, all revisions in our study were for component failure, whereas previous reports have described a higher rate for infection.²² However, the same studies also found glenoid lucency rates as high as 76% at 10-year follow-up.¹⁶ Furthermore, in a review of 136 TSAs with unsatisfactory outcomes, glenoid loosening was the most common reason for presenting to clinic after surgery.⁴⁴ Specifically, our population had a high rate of glenohumeral arthritis secondary to instability (50.0%) and posttraumatic osteoarthritis (26.9%). For many reasons, outcomes were worse in younger patients with a history of glenohumeral instability³³ than in older patients without a high incidence of instability.⁴⁵ This young cohort with higher demands may have had accelerated polyethylene wear patterns caused by repetitive overhead activity, which may have arisen because of a higher functional profile after surgery and greater patient expectations after arthroplasty. In addition, patients with a history of instability may have altered glenohumeral anatomy, especially with previous arthroscopic or open stabilization procedures. Anatomical changes include excessive posterior glenoid wear, internal rotation contracture, patulous capsular tissue, static or dynamic posterior humeral subluxation, and possible overconstraint after prior stabilization procedures. Almost half of our population had a previous surgery; our patients averaged 1.7 previous surgeries each.

Although estimates of component survivorship at a high-volume civilian tertiary-referral center were as high as 97% at 10 years and 84% at 20 years,^7,16 10-year survivorship in patients with a history of instability was only 61%.3 TSA survivorship in our young, active cohort is already foreseeably dramatically reduced, given the 23.1% revision rate at 28.5-month follow-up. This consideration must be addressed during preoperative counseling with the young patient with glenohumeral arthritis and a history of shoulder instability.

 

Despite the high rates of complications and revisions in our study, 92.3% of patients were satisfied with surgery, 88.0% experienced minimal persistence of pain (mean 3.8-point decrease on SRPS), and 100% maintained improved ROM at final follow-up. Satisfaction in the young population has varied significantly, from 52% to 95%, generally on the basis of physical activity.^16,22-24 The reasonable rate of postoperative satisfaction in the present analysis is comparable to what has been reported in patients of a similar age (Table 6).^7,16,22 However, despite high satisfaction and pain relief, patients were inconsistently able to return to the upper limits of physical activity required of active-duty military service. In addition, we cannot exclude secondary gain motivations for pursuing medical retirement, similar to that seen in patients receiving worker’s compensation.

Other authors have conversely found more favorable functional outcomes and survivorship rates.^23,24 In a retrospective review of 46 TSAs in patients 55 years or younger, Bartelt and colleagues²⁴ found sustained improvements in pain, ROM, and satisfaction at 7-year follow-up.24 Raiss and colleagues²³ conducted a prospective study of TSA outcomes in 21 patients with a mean age of 55 years and a mean follow-up of 7 years and reported no revisions and only 1 minor complication, a transient brachial plexus palsy.²³ The discrepancy between these studies may reflect different activity levels and underlying pathology between cohorts. The present population is unique in that it represents a particularly difficult confluence of factors for shoulder arthroplasty surgeons. The high activity, significant overhead and lifting occupational demands, and discordant patient expectations of this military cohort place a significant functional burden on the implants, the glenoid component in particular. Furthermore, this patient group has a higher incidence of more complex glenohumeral pathology resulting in instability, posttraumatic, or capsulorrhaphy arthropathy, and multiple prior arthroscopic and open stabilization procedures.

At final follow-up, only 33% of our patients were still on activity duty, 37.5% had completed or were completing medical separation from the military after surgery for persistent shoulder disability, and 37.5% were retired from the military. Five patients (20.8%) deployed after surgery. This young, active cohort of service members who had TSA for glenohumeral arthritis faced a unique set of tremendous physical demands. A retrospective case series investigated return to sport in 100 consecutive patients (mean age, 68.9 years) who were participating in recreational and competitive athletics and underwent unilateral TSA.²¹ The patients were engaged most commonly in swimming (20.4%), golf (16.3%), cycling (16.3%), and fitness training (16.3%). The authors found that, at a mean follow-up of 2.8 years, 49 patients (89%) were able to continue in sports, though 36.7% thought their sport activity was restricted after TSA. In another retrospective case series (61 TSAs), McCarty and colleagues¹⁹ found that 48 patients (71%) were improved in their sports participation, and 50% increased their frequency of participation after surgery.

There are no specific recommendations on returning to military service or high-level sport after surgery. Recommendations on returning to sport after TSA have been based largely on small case series involving specific sports^46,47 and surveys of expert opinion.^17,18 In a survey on postoperative physical activity in young patients after TSA conducted by Healy and colleagues,¹⁷ 35 American Shoulder and Elbow Surgeons members recommended avoiding contact and impact sports while permitting return to nonimpact sports, such as swimming, which may still impart significant stress to the glenohumeral joint. In an international survey of 101 shoulder and elbow surgeons, Magnussen and colleagues¹⁸ also found that most recommended avoiding a return to impact sports that require intensive upper extremity demands and permitting full return to sports at preoperative levels. This likely is a result of the perception that most of these patients having TSA are older and have less rigorous involvement in sports at the outset and a lower propensity for adverse patient outcomes. However, these recommendations may place a younger, more high-demand patient at significantly greater risk. The active-duty cohort engages in daily physical training, including push-ups and frequent overhead lifting, which could account for the high failure rates and low incidence of postoperative deployment. Although TSA seems to demonstrate good initial results in terms of return to high-demand activities, the return-to-duty profile in our study highlights the potential pitfalls of TSA in active individuals attempting to return to high-demand preoperative function.

 

Our analysis was limited by the fact that we used a small patient cohort, contributing to underpowered analysis of the potential risk factors predictive of reoperation and medical discharge. Although our minimum follow-up was 12 months, with the exception of 1 patient who was medically separated at 11.6 months because of shoulder disability, we captured 5 patients (19.2%) who underwent medical separation but who would otherwise be excluded. Therefore, this limitation is not major in that, with a longer minimum follow-up, we would be excluding a significant number of patients with such persistent disability after TSA that they would not be able to return to duty at anywhere near their previous level. In this retrospective study, we were additionally limited to analysis of the data in the medical records and could not control for variables such as surgeon technique, implant choice, and experience. Complete radiographic images were not available, limiting analysis of radiographic outcomes. Given the lack of a standardized preoperative imaging protocol, we could not evaluate glenoid version on axial imaging. It is possible that some patients with early aseptic glenoid loosening had posterior subluxation or a Walch B2 glenoid, which has a higher failure rate.⁴⁸ The strengths of this study include its unique analysis of a homogeneous young, active, high-risk patient cohort within a closed healthcare system. In the military, these patients are subject to intense daily physical and occupational demands. In addition, the clinical and functional outcomes we studied are patient-centered and therefore relevant during preoperative counseling. Further investigations might focus on validated outcome measures and on midterm to long-term TSA outcomes in an active military population vis-à-vis other alternatives for clinical management.

Conclusion

By a mean follow-up of 3.5 years, only a third of the service members had returned to active duty, roughly a third had retired, and more than a third had been medically discharged because of persistent disability attributable to the shoulder. Despite initial improvements in ROM and pain, midterm outcomes were poor. The short-term complication rate (46.2%) and the rate of reoperation for component failure (23.1%) should be emphasized during preoperative counseling.

Although total shoulder arthroplasty (TSA) has proved to be a reliable solution in older patients, treatment in younger patients with glenohumeral arthritis remains controversial, and there are still few reliable long-term surgical options.^1-8 These options include abrasion arthroplasty and arthroscopic management,^9,10 biologic glenoid resurfacing,^11,12 and humeral hemiarthroplasty with¹³ or without^14,15 glenoid treatment and anatomical TSA.

In the younger cohort, 20-year TSA survivorship rates up to 84% have been reported, and unsatisfactory subjective outcomes have been unacceptably high.¹⁶ In addition, there is a paucity of literature addressing the impact of TSA on return to sport. Recommendations on returning to an athletic life style are based largely on surveys of expert opinion^17,18 and heterogeneous studies of either older patients (eg, age >50-55 years) who are active^19-21 or younger patients with no defined level of activity.^{5,7,8,16,22-24}

To our knowledge, no one has evaluated the short-term morbidity and clinical outcomes within a young, high-demand patient population, such as the US military. Therefore, we conducted a study to evaluate the clinical success and complications of TSA performed for glenohumeral arthritis in a young, active population. We hypothesized that patients who had undergone TSA would have a low rate of return to duty, an increased rate of component failure, and a higher reoperation rate because of increased upper extremity demands.

Materials and Methods

After obtaining protocol approval from the William Beaumont Army Medical Center Institutional Review Board, we searched the Military Health System (MHS) Management Analysis and Reporting Tool (M2) database to retrospectively review the cases of all tri-service US military service members who had undergone primary anatomical TSA (Current Procedural Terminology code 23472) between January 1, 2007 and June 31, 2014. This was a multisurgeon, multicenter study. Patient exclusion criteria were nonmilitary or retired status at time of surgery; primary surgery consisting of limited glenohumeral resurfacing procedure, hemiarthroplasty, or reverse TSA; surgery for acute proximal humerus fracture; rotator cuff deficiency diagnosed before or during surgery; and insufficient follow-up (eg, <12 months, unless medically separated beforehand).

The M2 database is an established tool that has been used for clinical outcomes research on treatment of a variety of orthopedic conditions.25,26 The Medical Data Repository, which is operated by MHS, is populated by its military healthcare providers. The MHS, which offers worldwide coverage for all beneficiaries either at Department of Defense facilities or purchased using civilian providers, is among the largest known closed healthcare systems.

All active-duty US military service members are uniformly required to adhere to stringent and regularly evaluated physical fitness standards, which typically exceed those of average civilians. Routine physical training is required in the form of aerobic fitness, weight training, tactical field exercises, and core military tasks, such as the ability to march at least 2 miles while carrying heavy fighting loads. In addition to satisfying required height and weight standards, all service members are subject to semiannual service-specific physical fitness evaluations inclusive of timed push-ups, sit-ups, and an aerobic event. Service members may also be required to maintain a level of physical training above these baseline standards, contingent on their branch of service, rank, and military occupational specialty. If a service member is unable to maintain these standards, medical separation may be initiated.

Demographic and occupational data were extracted from the database. These data included age, sex, military rank, and branch of service. Line-by-line analysis of the Armed Forces Health Longitudinal Technology Application (Version 22; 3M) electronic medical record was then performed to confirm the underlying diagnosis, surgical procedure, and surgery date. Further chart review yielded additional patient-based factors (eg, laterality, hand dominance, presence and type of prior shoulder surgeries) and surgical factors (eg, surgery indication, implant design). We evaluated clinical and functional outcomes as well as perioperative complications, including both major and minor systemic and local complications as previously described^27,28; preoperative and postoperative range of motion (ROM) and self-reported pain score (SRPS, scale 1-10) as measured by physical therapist and surgeon at follow-up; secondary surgical interventions; timing of return to duty; and postoperative deployment history. The primary outcome measures were revision reoperation after index procedure, and military discharge for persistent shoulder-related disability. Clinical failure was defined as component failure or reoperation. Medical Evaluation Board (MEB) is a formal separation from the military in which it is deemed that a service member is no longer able to fulfill his or her duty because of a medical condition.

 

Statistical Analysis

Continuous variables were compared using statistical means with 95% confidence intervals (CIs) and/or SDs. Categorical data were reported as frequencies or percentages. Univariate analysis was performed to assess the correlation between possible risk factors and the primary outcome measures. P < .05 was considered statistically significant.

Results

Demographics

We identified 24 service members (26 shoulders) who had undergone anatomical TSA during the study period (Table 1). Mean (SD) age was 45.8 (4.5) years (range, 35-54 years), and the cohort was predominately male (25/26 shoulders; 96.2%). Most cohort members were of senior enlisted rank (14, 58.3%), and the US Army was the predominant branch of military service (13, 54.2%). The right side was the operative extremity in 7 cases (26.9%), and the dominant shoulder was involved in 6 cases (23.1%). Two patients (8.3%) underwent staged bilateral TSA. Most patients (76.9%) underwent TSA on the nondominant extremity.

Surgical Variables

TSA was indicated for post-instability arthropathy in 13 cases (50.0%), posttraumatic osteoarthritis in 7 cases (26.9%), and unspecified glenohumeral arthritis, which includes primary glenohumeral osteoarthritis, in 5 cases (19.2%) (Table 2). One case was attributed to iatrogenically induced chondrolysis secondary to intra-articular lidocaine pump. Twelve patients (46.2%) had at least 1 previous surgery. Of the shoulders with instability, 10 (76.9%) had undergone a total of 14 surgical stabilization procedures—10 anterior labral repairs, 2 posterior labral repairs, and 2 capsular plications. The other shoulders had undergone a total of 18 procedures, which included 4 rotator cuff repairs and 3 cartilage restoration procedures.

Clinical Outcomes

Mean (SD) follow-up was 41.0 (21.3) months (range, 11.6-97.6 months). All but 1 shoulder (96.2%) had follow-up of 12 months or more (the only patient with shorter follow-up was because of MEB), and 76.9% of patients had follow-up of 24 months or more (4 of the 6 patients with follow-up under 24 months were medically separated) (Table 3). In all cases, mean ROM improved with respect to flexion, abduction, and external rotation. At final follow-up, mean (SD) ROM was 138° (36°) forward flexion (range, 60°-180°), 125° (39°) abduction (range, 45°-180°), 48° (19°) external rotation at 0° abduction (range, 20°-90°), and 80° (9.4°) external rotation at 90° abduction (range, 70°-90°). Preoperative flexion, abduction, and external rotation at 0° and 90° abduction were all improved at final follow-up. The most improvement in ROM occurred within 6 months after surgery.

Overall patient satisfaction with surgery was 92.3% (n = 24). Ultimately, 18 (72.0%) of 25 shoulders with follow-up of 1 year or more were able to return to active duty within 1 year after surgery, though only 10 (45.5%) of 22 with follow-up of 2 years or more remained active 2 years after surgery. Furthermore, 5 patients (20.8%) were deployed after surgery, and all were still on active duty at final follow-up. By final follow-up, 9 (37.5%) of 24 service members were unable to return to military function; 7 had been medically discharged from the military for persistent shoulder disability, and 2 were in the process of being medically discharged.

In all cases, SRPS improved from before surgery (5.2 out of 10) to final follow-up (1.4). At final follow-up, 22 patients (88.0%) reported mild pain (0-3), and no one had pain above 6.

 

Complications

Nine patients had a total of 12 postoperative complications (46.2%): 6 component failures (23.1%), 2 neurologic injuries (7.7%; 1 permanent axillary nerve injury, 1 transient brachial plexus neuritis), 2 cases of adhesive capsulitis (7.7%), and 2 episodes of venous thrombosis (7.7%; 1 superficial, 1 deep) (Table 4). There were no documented infections. Six reoperations (23.1%) were performed for the 6 component failures (2 traumatic dislocations of prosthesis resulting in acute glenoid component failure, 3 cases of atraumatic glenoid loosening, 1 case of humeral stem loosening after periprosthetic fracture). Atraumatic glenoid component loosening occurred a mean (SD) of 40.6 (14.2) months after surgery (range, 20.8-54.2 months).

Surgical Failures

Eight service members underwent MEB. Six patients experienced component failure. Factors contributing to both clinical failure and separation from active duty by means of MEB were evaluated with univariate analysis (Table 5). No statistically significant risk factors, including surgical revision and presence of perioperative complications, were identified.

Discussion

We confirmed that our cohort of young service members (mean age, 45.8 years), who had undergone TSA for glenohumeral arthritis, had a relatively higher rate of component failure (23.1%) and a higher reoperation rate (23.1%) with low rates of return to military duty at short-term to midterm follow-up. Our results parallel those of a limited series with a younger cohort (Table 6).^{7,16,19,21,23,24} The high demand and increased life expectancy of the younger patients with glenohumeral arthritis potentiates the risk of complications, component loosening, and ultimate failure.²⁹ To our knowledge, the present article is the first to report clinical and functional outcomes and perioperative risk profiles in a homogenously young, active military cohort after TSA.

 

The mean age of our study population (46 years) is one of the lowest in the literature. TSA in younger patients (age, <50-55 years) and older, active patients (>55 years) has received increased attention as a result of the expanding indications and growing popularity of TSA in these groups. Other studies have upheld the efficacy of TSA in achieving predictable pain relief and functional improvement in a diverse and predominantly elderly population.^15,30-34 Alternative treatments, including humeral head resurfacing^15,30,35 and soft-tissue interposition,^15,36-40 have also shown inferior short- and long-term results in terms of longevity and degree of clinical or functional improvement.^31-34,41 In addition, the ream-and-run technique has had promising early results by improving glenohumeral kinematics, pain relief, and shoulder function.^13,42,43 However, although implantation of a glenoid component is avoided in young, active people because of reduced longevity and higher rates of component failure, the trade-offs are inadequately treated glenoid disease, suboptimal pain relief, and progression of glenoid arthritis eventually requiring revision. Furthermore, midterm and long-term survivorship of TSA in general is unknown, and there remain few good options for treating end-stage arthritis in young, active patients.

Our cohort had high rates of complications (46.2%) and revisions (23.1%). Two in 5 patients had postoperative complications, most commonly component failure resulting in reoperation. In the literature, complication rates among young patients who underwent TSA are much lower (4.8%-10.9%).^16,23,24 Our cohort’s most common complication was component failure (23.1%), which was most often attributed to atraumatic, aseptic glenoid component loosening and required reoperation. Previously reported revision rates in a young population that underwent TSA (0%-11%)^16,23,24 were also significantly lower than those in the present analysis (23.1%), underscoring the impact of operative indications, postoperative activity levels, and occupational demands on ultimate failure rates. Interestingly, all revisions in our study were for component failure, whereas previous reports have described a higher rate for infection.²² However, the same studies also found glenoid lucency rates as high as 76% at 10-year follow-up.¹⁶ Furthermore, in a review of 136 TSAs with unsatisfactory outcomes, glenoid loosening was the most common reason for presenting to clinic after surgery.⁴⁴ Specifically, our population had a high rate of glenohumeral arthritis secondary to instability (50.0%) and posttraumatic osteoarthritis (26.9%). For many reasons, outcomes were worse in younger patients with a history of glenohumeral instability³³ than in older patients without a high incidence of instability.⁴⁵ This young cohort with higher demands may have had accelerated polyethylene wear patterns caused by repetitive overhead activity, which may have arisen because of a higher functional profile after surgery and greater patient expectations after arthroplasty. In addition, patients with a history of instability may have altered glenohumeral anatomy, especially with previous arthroscopic or open stabilization procedures. Anatomical changes include excessive posterior glenoid wear, internal rotation contracture, patulous capsular tissue, static or dynamic posterior humeral subluxation, and possible overconstraint after prior stabilization procedures. Almost half of our population had a previous surgery; our patients averaged 1.7 previous surgeries each.

Although estimates of component survivorship at a high-volume civilian tertiary-referral center were as high as 97% at 10 years and 84% at 20 years,^7,16 10-year survivorship in patients with a history of instability was only 61%.3 TSA survivorship in our young, active cohort is already foreseeably dramatically reduced, given the 23.1% revision rate at 28.5-month follow-up. This consideration must be addressed during preoperative counseling with the young patient with glenohumeral arthritis and a history of shoulder instability.

 

Despite the high rates of complications and revisions in our study, 92.3% of patients were satisfied with surgery, 88.0% experienced minimal persistence of pain (mean 3.8-point decrease on SRPS), and 100% maintained improved ROM at final follow-up. Satisfaction in the young population has varied significantly, from 52% to 95%, generally on the basis of physical activity.^16,22-24 The reasonable rate of postoperative satisfaction in the present analysis is comparable to what has been reported in patients of a similar age (Table 6).^7,16,22 However, despite high satisfaction and pain relief, patients were inconsistently able to return to the upper limits of physical activity required of active-duty military service. In addition, we cannot exclude secondary gain motivations for pursuing medical retirement, similar to that seen in patients receiving worker’s compensation.

Other authors have conversely found more favorable functional outcomes and survivorship rates.^23,24 In a retrospective review of 46 TSAs in patients 55 years or younger, Bartelt and colleagues²⁴ found sustained improvements in pain, ROM, and satisfaction at 7-year follow-up.24 Raiss and colleagues²³ conducted a prospective study of TSA outcomes in 21 patients with a mean age of 55 years and a mean follow-up of 7 years and reported no revisions and only 1 minor complication, a transient brachial plexus palsy.²³ The discrepancy between these studies may reflect different activity levels and underlying pathology between cohorts. The present population is unique in that it represents a particularly difficult confluence of factors for shoulder arthroplasty surgeons. The high activity, significant overhead and lifting occupational demands, and discordant patient expectations of this military cohort place a significant functional burden on the implants, the glenoid component in particular. Furthermore, this patient group has a higher incidence of more complex glenohumeral pathology resulting in instability, posttraumatic, or capsulorrhaphy arthropathy, and multiple prior arthroscopic and open stabilization procedures.

At final follow-up, only 33% of our patients were still on activity duty, 37.5% had completed or were completing medical separation from the military after surgery for persistent shoulder disability, and 37.5% were retired from the military. Five patients (20.8%) deployed after surgery. This young, active cohort of service members who had TSA for glenohumeral arthritis faced a unique set of tremendous physical demands. A retrospective case series investigated return to sport in 100 consecutive patients (mean age, 68.9 years) who were participating in recreational and competitive athletics and underwent unilateral TSA.²¹ The patients were engaged most commonly in swimming (20.4%), golf (16.3%), cycling (16.3%), and fitness training (16.3%). The authors found that, at a mean follow-up of 2.8 years, 49 patients (89%) were able to continue in sports, though 36.7% thought their sport activity was restricted after TSA. In another retrospective case series (61 TSAs), McCarty and colleagues¹⁹ found that 48 patients (71%) were improved in their sports participation, and 50% increased their frequency of participation after surgery.

There are no specific recommendations on returning to military service or high-level sport after surgery. Recommendations on returning to sport after TSA have been based largely on small case series involving specific sports^46,47 and surveys of expert opinion.^17,18 In a survey on postoperative physical activity in young patients after TSA conducted by Healy and colleagues,¹⁷ 35 American Shoulder and Elbow Surgeons members recommended avoiding contact and impact sports while permitting return to nonimpact sports, such as swimming, which may still impart significant stress to the glenohumeral joint. In an international survey of 101 shoulder and elbow surgeons, Magnussen and colleagues¹⁸ also found that most recommended avoiding a return to impact sports that require intensive upper extremity demands and permitting full return to sports at preoperative levels. This likely is a result of the perception that most of these patients having TSA are older and have less rigorous involvement in sports at the outset and a lower propensity for adverse patient outcomes. However, these recommendations may place a younger, more high-demand patient at significantly greater risk. The active-duty cohort engages in daily physical training, including push-ups and frequent overhead lifting, which could account for the high failure rates and low incidence of postoperative deployment. Although TSA seems to demonstrate good initial results in terms of return to high-demand activities, the return-to-duty profile in our study highlights the potential pitfalls of TSA in active individuals attempting to return to high-demand preoperative function.

 

Our analysis was limited by the fact that we used a small patient cohort, contributing to underpowered analysis of the potential risk factors predictive of reoperation and medical discharge. Although our minimum follow-up was 12 months, with the exception of 1 patient who was medically separated at 11.6 months because of shoulder disability, we captured 5 patients (19.2%) who underwent medical separation but who would otherwise be excluded. Therefore, this limitation is not major in that, with a longer minimum follow-up, we would be excluding a significant number of patients with such persistent disability after TSA that they would not be able to return to duty at anywhere near their previous level. In this retrospective study, we were additionally limited to analysis of the data in the medical records and could not control for variables such as surgeon technique, implant choice, and experience. Complete radiographic images were not available, limiting analysis of radiographic outcomes. Given the lack of a standardized preoperative imaging protocol, we could not evaluate glenoid version on axial imaging. It is possible that some patients with early aseptic glenoid loosening had posterior subluxation or a Walch B2 glenoid, which has a higher failure rate.⁴⁸ The strengths of this study include its unique analysis of a homogeneous young, active, high-risk patient cohort within a closed healthcare system. In the military, these patients are subject to intense daily physical and occupational demands. In addition, the clinical and functional outcomes we studied are patient-centered and therefore relevant during preoperative counseling. Further investigations might focus on validated outcome measures and on midterm to long-term TSA outcomes in an active military population vis-à-vis other alternatives for clinical management.

Conclusion

By a mean follow-up of 3.5 years, only a third of the service members had returned to active duty, roughly a third had retired, and more than a third had been medically discharged because of persistent disability attributable to the shoulder. Despite initial improvements in ROM and pain, midterm outcomes were poor. The short-term complication rate (46.2%) and the rate of reoperation for component failure (23.1%) should be emphasized during preoperative counseling.

Rotator cuff tears are very common, and 250,000 to 500,000 rotator cuff repairs are performed in the United States each year.^1,2 In most cases, a complete repair of even large or massive tears can be achieved. However, a subset of patients exist in whom the glenohumeral joint has minimal degenerative changes and the rotator cuff tendon is either irreparable or very poor quality and unlikely to heal (ie, failed previous cuff repair). Some authors have advocated for reverse shoulder arthroplasty (RSA) in these patients despite the lack of glenohumeral arthritis. However, due to the permanent destruction of the glenohumeral articular surfaces, complication rates, and concerns about implant longevity with RSA, we believe the superior capsular reconstruction (SCR) is a viable alternative in patients in whom joint preservation is appropriate based on age limitations and/or activity requirements.³

The SCR was first described by Mihata and colleagues4 as a means to reconstruct the superior capsule in shoulders with large, irreparable posterosuperior rotator cuff tears. Originally described using a fascia lata autograft, our technique has been adapted to incorporate a dermal allograft, which limits donor site morbidity and operative time. In most cases, the dermal allograft is fixed to the normal anatomic attachments of the superior glenoid just medial to the superior labrum, laterally to the greater tuberosity, and posteriorly with side-to-side sutures to the remaining rotator cuff. If there is a robust band of “comma” tissue anteriorly, we fix the anterior margin of the dermal graft to this with side-to-side sutures. The comma tissue represents the medial sling of the biceps tendon and connects the upper subscapularis tendon to the anterior supraspinatus. In most cases, this tissue is intact after repair of the subscapularis tendon.

Technique

The patient is positioned in either the lateral decubitus or beach chair position. The arm is positioned in 20° to 30° of abduction and 20° to 30° of forward flexion. A diagnostic arthroscopy is performed through a posterior glenohumeral viewing portal. The subscapularis is visualized and repaired if torn. A biceps tenodesis is performed in most cases, as there is often a tear of the subscapularis, tear or instability of the biceps tendon, and/or a compromised attachment of the biceps root.

Attention is turned to the subacromial space. Posterior viewing and lateral working portals are established. A 10-mm flexible cannula (PassPort; Arthrex) is placed in the lateral portal to aid with suture management and graft passage. A limited subacromial decompression is performed that preserves the coracoacromial arch. The rotator cuff is carefully dissected and freed from the internal deltoid fascia. The scapular spine is identified to visualize the raphé between the supraspinatus and infraspinatus. The infraspinatus is mobilized and repaired as much as possible.

If we think that the tear might be reparable by gaining added excursion from a posterior interval slide, or if it is clearly not reparable but the remaining rim of rotator cuff obscures clear visualization of the superior glenoid, we perform a posterior interval slide. If the additional excursion that is achieved by the posterior slide is adequate for a complete repair, we proceed with the repair. However, if the tear is not reparable even after the posterior interval slide, we have found that the exposure and preparation of the superior glenoid is greatly improved after the posterior slide. After fixation of the dermal graft, we typically perform a partial side-to-side repair of the supraspinatus to the infraspinatus over the top of the graft.

The bone beds of the greater tuberosity and just medial to the superior glenoid labrum are prepared with a shaver and motorized burr. Two anchors (3.0-mm BioComposite SutureTak; Arthrex) are placed in the superior glenoid neck at about the 10 o’clock and 2 o’clock positions approximately 5 mm medial to the superior labrum. Note: the placement medial to the labrum is chosen because this is the normal origin of the superior capsule and because of the angle of approach, these percutaneous portals are often more medial than typical portals for placing anchors during SLAP (superior labral anterior to posterior) repair. Next, 2 threaded anchors (4.75-mm BioComposite SwiveLock; Arthrex) preloaded with suture tape are placed in the greater tuberosity along the articular margin (Figure 1). However, if a biceps tenodesis with an interference screw is placed at the top of the bicipital groove, this anchor preloaded with suture tape can also serve as the anteromedial anchor in the greater tuberosity footprint. The distances between all 4 anchors are carefully measured with a calibrated probe (Figures 2A-2D).

 

 

 

We use a 3.0-mm acellular dermal allograft (ArthroFlex; Arthrex) to reconstruct the superior capsule. The positions of the 4 anchors are carefully marked on the dermal allograft. We routinely add an additional 5 mm of tissue to the medial, anterior, and posterior margins to decrease the risk of suture cut out. An additional 10 mm of tissue is added laterally to cover the greater tuberosity. The final contoured graft is typically trapezoidal in shape.

The sutures from the 4 anchors are then sequentially retrieved through the lateral cannula. The sutures from the greater tuberosity anchors are passed through their respective holes in the graft. However, the suture limbs from each of the glenoid anchors are individually passed 2 mm anterior and 2 mm posterior to their respective marks on the graft with an antegrade suture passer (Figure 3). It is important to have an assistant apply tension to each of the sutures after they are passed through the graft to decrease the chance of crossing and tangling the sutures.

The eyelets of the medial anchors are utilized as pulleys to deliver the dermal allograft into the shoulder. One suture limb from each of the glenoid anchors is tied to the other over a switching stick (Figure 4A). The 2 remaining (untied) suture limbs are then pulled, which introduces the graft to the orifice of the cannula (Figure 4B). A tissue grasper is then used to fold the dermal allograft along its long axis and introduce the graft into the joint (Figure 4C). Once the medial portion of the graft is positioned onto the superior glenoid the 2 remaining (untied) suture limbs are tied to each other as a static knot in the subacromial space (Figure 4D).

The redundancy in the suture tapes can be removed by sequentially sliding a retriever down each suture and tensioning the suture as the nose of the instrument pushes the dermal graft down to the tuberosity bone bed. The suture tapes are crisscrossed and secured laterally with 2 additional knotless threaded anchors (Figure 5). One may also place cinch stitches at the anterolateral and posterolateral corners of the graft that are incorporated into the lateral anchors. These sutures can be useful for pulling the graft back out of the subacromial space in the event of any suture tangles, and can be used for controlling the lateral aspect of the graft during lateral anchor placement.

 

 

At this point in the procedure, additional glenoid anchors can be placed both anterior and posterior to the superior glenoid anchors if additional glenoid fixation is desired. Finally, 2 to 3 side-to-side sutures are placed posteriorly attaching the anterior aspect of the infraspinatus to the posterior aspect of the dermal allograft (Figures 6A-6C). If rotator interval tissue (comma tissue) is present, anterior side-to-side sutures may be placed. However, we do not recommend placing anterior side-to-side sutures directly from the dermal allograft to the subscapularis as this may deform the graft, over- constrain the shoulder, and restrict motion.

Discussion

Reconstruction of the superior capsule has been shown to restore the normal restraint to superior translation of the humeral head and reestablish a stable fulcrum at the glenohumeral joint.⁵ It should be mentioned that we do not perform the SCR in patients with advanced glenohumeral arthritis. The short-term results of this novel procedure have been encouraging, including our own series of patients, in which most patients have had a significant reduction in pain, improvement in function, and very few complications (P. J. Denard, MD, S. S. Burkhart, MD, P. C. Brady, MD, J. Tokish, MD, C. R. Adams, MD, unpublished data, May 2016).

The early success of this procedure suggests that a robust superior capsule is necessary, in addition to functional muscle-tendon units, to restore the stable fulcrum and force couples that are necessary for normal shoulder function. Perhaps we have not paid enough attention to the integrity of the superior capsule in the past. In cases of revision cuff repair, we pay special attention to the quality of the capsular layer deep to the cuff tendon. If the capsule is poor quality, we sometimes reconstruct the capsule with a dermal allograft (SCR) and then do a rotator cuff repair (partial or complete) over the top of the SCR to maintain the normal anatomic deep to superficial layering of the capsule and rotator cuff.

We are very conservative with our postoperative rehabilitation program after a SCR. We know that the rate of stiffness with a conservative program after an arthroscopic rotator cuff repair, even in the revision setting, is very low.⁶ Furthermore, both basic science on healing of soft tissue to bone and radiographic analysis of healing after postoperative rotator cuff repairs support a slow rehabilitation program.^7,8 A canine model specifically evaluating acellular dermal allografts in the shoulder suggests that these grafts undergo significant remodeling and become weaker before they get stronger.⁹ We would rather err on the side of healing of the SCR with potentially a slight increase in the rate of shoulder stiffness than to regain early motion at the expense of graft failure. Therefore, we have the patient wear a sling with no shoulder motion for 6 weeks. Passive motion is started at 6 weeks postoperative and strengthening is delayed until 12 to 16 weeks postoperative.

Rotator cuff tears are very common, and 250,000 to 500,000 rotator cuff repairs are performed in the United States each year.^1,2 In most cases, a complete repair of even large or massive tears can be achieved. However, a subset of patients exist in whom the glenohumeral joint has minimal degenerative changes and the rotator cuff tendon is either irreparable or very poor quality and unlikely to heal (ie, failed previous cuff repair). Some authors have advocated for reverse shoulder arthroplasty (RSA) in these patients despite the lack of glenohumeral arthritis. However, due to the permanent destruction of the glenohumeral articular surfaces, complication rates, and concerns about implant longevity with RSA, we believe the superior capsular reconstruction (SCR) is a viable alternative in patients in whom joint preservation is appropriate based on age limitations and/or activity requirements.³

The SCR was first described by Mihata and colleagues4 as a means to reconstruct the superior capsule in shoulders with large, irreparable posterosuperior rotator cuff tears. Originally described using a fascia lata autograft, our technique has been adapted to incorporate a dermal allograft, which limits donor site morbidity and operative time. In most cases, the dermal allograft is fixed to the normal anatomic attachments of the superior glenoid just medial to the superior labrum, laterally to the greater tuberosity, and posteriorly with side-to-side sutures to the remaining rotator cuff. If there is a robust band of “comma” tissue anteriorly, we fix the anterior margin of the dermal graft to this with side-to-side sutures. The comma tissue represents the medial sling of the biceps tendon and connects the upper subscapularis tendon to the anterior supraspinatus. In most cases, this tissue is intact after repair of the subscapularis tendon.

Technique

The patient is positioned in either the lateral decubitus or beach chair position. The arm is positioned in 20° to 30° of abduction and 20° to 30° of forward flexion. A diagnostic arthroscopy is performed through a posterior glenohumeral viewing portal. The subscapularis is visualized and repaired if torn. A biceps tenodesis is performed in most cases, as there is often a tear of the subscapularis, tear or instability of the biceps tendon, and/or a compromised attachment of the biceps root.

Attention is turned to the subacromial space. Posterior viewing and lateral working portals are established. A 10-mm flexible cannula (PassPort; Arthrex) is placed in the lateral portal to aid with suture management and graft passage. A limited subacromial decompression is performed that preserves the coracoacromial arch. The rotator cuff is carefully dissected and freed from the internal deltoid fascia. The scapular spine is identified to visualize the raphé between the supraspinatus and infraspinatus. The infraspinatus is mobilized and repaired as much as possible.

If we think that the tear might be reparable by gaining added excursion from a posterior interval slide, or if it is clearly not reparable but the remaining rim of rotator cuff obscures clear visualization of the superior glenoid, we perform a posterior interval slide. If the additional excursion that is achieved by the posterior slide is adequate for a complete repair, we proceed with the repair. However, if the tear is not reparable even after the posterior interval slide, we have found that the exposure and preparation of the superior glenoid is greatly improved after the posterior slide. After fixation of the dermal graft, we typically perform a partial side-to-side repair of the supraspinatus to the infraspinatus over the top of the graft.

The bone beds of the greater tuberosity and just medial to the superior glenoid labrum are prepared with a shaver and motorized burr. Two anchors (3.0-mm BioComposite SutureTak; Arthrex) are placed in the superior glenoid neck at about the 10 o’clock and 2 o’clock positions approximately 5 mm medial to the superior labrum. Note: the placement medial to the labrum is chosen because this is the normal origin of the superior capsule and because of the angle of approach, these percutaneous portals are often more medial than typical portals for placing anchors during SLAP (superior labral anterior to posterior) repair. Next, 2 threaded anchors (4.75-mm BioComposite SwiveLock; Arthrex) preloaded with suture tape are placed in the greater tuberosity along the articular margin (Figure 1). However, if a biceps tenodesis with an interference screw is placed at the top of the bicipital groove, this anchor preloaded with suture tape can also serve as the anteromedial anchor in the greater tuberosity footprint. The distances between all 4 anchors are carefully measured with a calibrated probe (Figures 2A-2D).

 

 

 

We use a 3.0-mm acellular dermal allograft (ArthroFlex; Arthrex) to reconstruct the superior capsule. The positions of the 4 anchors are carefully marked on the dermal allograft. We routinely add an additional 5 mm of tissue to the medial, anterior, and posterior margins to decrease the risk of suture cut out. An additional 10 mm of tissue is added laterally to cover the greater tuberosity. The final contoured graft is typically trapezoidal in shape.

The sutures from the 4 anchors are then sequentially retrieved through the lateral cannula. The sutures from the greater tuberosity anchors are passed through their respective holes in the graft. However, the suture limbs from each of the glenoid anchors are individually passed 2 mm anterior and 2 mm posterior to their respective marks on the graft with an antegrade suture passer (Figure 3). It is important to have an assistant apply tension to each of the sutures after they are passed through the graft to decrease the chance of crossing and tangling the sutures.

The eyelets of the medial anchors are utilized as pulleys to deliver the dermal allograft into the shoulder. One suture limb from each of the glenoid anchors is tied to the other over a switching stick (Figure 4A). The 2 remaining (untied) suture limbs are then pulled, which introduces the graft to the orifice of the cannula (Figure 4B). A tissue grasper is then used to fold the dermal allograft along its long axis and introduce the graft into the joint (Figure 4C). Once the medial portion of the graft is positioned onto the superior glenoid the 2 remaining (untied) suture limbs are tied to each other as a static knot in the subacromial space (Figure 4D).

The redundancy in the suture tapes can be removed by sequentially sliding a retriever down each suture and tensioning the suture as the nose of the instrument pushes the dermal graft down to the tuberosity bone bed. The suture tapes are crisscrossed and secured laterally with 2 additional knotless threaded anchors (Figure 5). One may also place cinch stitches at the anterolateral and posterolateral corners of the graft that are incorporated into the lateral anchors. These sutures can be useful for pulling the graft back out of the subacromial space in the event of any suture tangles, and can be used for controlling the lateral aspect of the graft during lateral anchor placement.

 

 

At this point in the procedure, additional glenoid anchors can be placed both anterior and posterior to the superior glenoid anchors if additional glenoid fixation is desired. Finally, 2 to 3 side-to-side sutures are placed posteriorly attaching the anterior aspect of the infraspinatus to the posterior aspect of the dermal allograft (Figures 6A-6C). If rotator interval tissue (comma tissue) is present, anterior side-to-side sutures may be placed. However, we do not recommend placing anterior side-to-side sutures directly from the dermal allograft to the subscapularis as this may deform the graft, over- constrain the shoulder, and restrict motion.

Discussion

Reconstruction of the superior capsule has been shown to restore the normal restraint to superior translation of the humeral head and reestablish a stable fulcrum at the glenohumeral joint.⁵ It should be mentioned that we do not perform the SCR in patients with advanced glenohumeral arthritis. The short-term results of this novel procedure have been encouraging, including our own series of patients, in which most patients have had a significant reduction in pain, improvement in function, and very few complications (P. J. Denard, MD, S. S. Burkhart, MD, P. C. Brady, MD, J. Tokish, MD, C. R. Adams, MD, unpublished data, May 2016).

The early success of this procedure suggests that a robust superior capsule is necessary, in addition to functional muscle-tendon units, to restore the stable fulcrum and force couples that are necessary for normal shoulder function. Perhaps we have not paid enough attention to the integrity of the superior capsule in the past. In cases of revision cuff repair, we pay special attention to the quality of the capsular layer deep to the cuff tendon. If the capsule is poor quality, we sometimes reconstruct the capsule with a dermal allograft (SCR) and then do a rotator cuff repair (partial or complete) over the top of the SCR to maintain the normal anatomic deep to superficial layering of the capsule and rotator cuff.

We are very conservative with our postoperative rehabilitation program after a SCR. We know that the rate of stiffness with a conservative program after an arthroscopic rotator cuff repair, even in the revision setting, is very low.⁶ Furthermore, both basic science on healing of soft tissue to bone and radiographic analysis of healing after postoperative rotator cuff repairs support a slow rehabilitation program.^7,8 A canine model specifically evaluating acellular dermal allografts in the shoulder suggests that these grafts undergo significant remodeling and become weaker before they get stronger.⁹ We would rather err on the side of healing of the SCR with potentially a slight increase in the rate of shoulder stiffness than to regain early motion at the expense of graft failure. Therefore, we have the patient wear a sling with no shoulder motion for 6 weeks. Passive motion is started at 6 weeks postoperative and strengthening is delayed until 12 to 16 weeks postoperative.

Rotator cuff tears are very common, and 250,000 to 500,000 rotator cuff repairs are performed in the United States each year.^1,2 In most cases, a complete repair of even large or massive tears can be achieved. However, a subset of patients exist in whom the glenohumeral joint has minimal degenerative changes and the rotator cuff tendon is either irreparable or very poor quality and unlikely to heal (ie, failed previous cuff repair). Some authors have advocated for reverse shoulder arthroplasty (RSA) in these patients despite the lack of glenohumeral arthritis. However, due to the permanent destruction of the glenohumeral articular surfaces, complication rates, and concerns about implant longevity with RSA, we believe the superior capsular reconstruction (SCR) is a viable alternative in patients in whom joint preservation is appropriate based on age limitations and/or activity requirements.³

The SCR was first described by Mihata and colleagues4 as a means to reconstruct the superior capsule in shoulders with large, irreparable posterosuperior rotator cuff tears. Originally described using a fascia lata autograft, our technique has been adapted to incorporate a dermal allograft, which limits donor site morbidity and operative time. In most cases, the dermal allograft is fixed to the normal anatomic attachments of the superior glenoid just medial to the superior labrum, laterally to the greater tuberosity, and posteriorly with side-to-side sutures to the remaining rotator cuff. If there is a robust band of “comma” tissue anteriorly, we fix the anterior margin of the dermal graft to this with side-to-side sutures. The comma tissue represents the medial sling of the biceps tendon and connects the upper subscapularis tendon to the anterior supraspinatus. In most cases, this tissue is intact after repair of the subscapularis tendon.

Technique

The patient is positioned in either the lateral decubitus or beach chair position. The arm is positioned in 20° to 30° of abduction and 20° to 30° of forward flexion. A diagnostic arthroscopy is performed through a posterior glenohumeral viewing portal. The subscapularis is visualized and repaired if torn. A biceps tenodesis is performed in most cases, as there is often a tear of the subscapularis, tear or instability of the biceps tendon, and/or a compromised attachment of the biceps root.

Attention is turned to the subacromial space. Posterior viewing and lateral working portals are established. A 10-mm flexible cannula (PassPort; Arthrex) is placed in the lateral portal to aid with suture management and graft passage. A limited subacromial decompression is performed that preserves the coracoacromial arch. The rotator cuff is carefully dissected and freed from the internal deltoid fascia. The scapular spine is identified to visualize the raphé between the supraspinatus and infraspinatus. The infraspinatus is mobilized and repaired as much as possible.

If we think that the tear might be reparable by gaining added excursion from a posterior interval slide, or if it is clearly not reparable but the remaining rim of rotator cuff obscures clear visualization of the superior glenoid, we perform a posterior interval slide. If the additional excursion that is achieved by the posterior slide is adequate for a complete repair, we proceed with the repair. However, if the tear is not reparable even after the posterior interval slide, we have found that the exposure and preparation of the superior glenoid is greatly improved after the posterior slide. After fixation of the dermal graft, we typically perform a partial side-to-side repair of the supraspinatus to the infraspinatus over the top of the graft.

The bone beds of the greater tuberosity and just medial to the superior glenoid labrum are prepared with a shaver and motorized burr. Two anchors (3.0-mm BioComposite SutureTak; Arthrex) are placed in the superior glenoid neck at about the 10 o’clock and 2 o’clock positions approximately 5 mm medial to the superior labrum. Note: the placement medial to the labrum is chosen because this is the normal origin of the superior capsule and because of the angle of approach, these percutaneous portals are often more medial than typical portals for placing anchors during SLAP (superior labral anterior to posterior) repair. Next, 2 threaded anchors (4.75-mm BioComposite SwiveLock; Arthrex) preloaded with suture tape are placed in the greater tuberosity along the articular margin (Figure 1). However, if a biceps tenodesis with an interference screw is placed at the top of the bicipital groove, this anchor preloaded with suture tape can also serve as the anteromedial anchor in the greater tuberosity footprint. The distances between all 4 anchors are carefully measured with a calibrated probe (Figures 2A-2D).

 

 

 

We use a 3.0-mm acellular dermal allograft (ArthroFlex; Arthrex) to reconstruct the superior capsule. The positions of the 4 anchors are carefully marked on the dermal allograft. We routinely add an additional 5 mm of tissue to the medial, anterior, and posterior margins to decrease the risk of suture cut out. An additional 10 mm of tissue is added laterally to cover the greater tuberosity. The final contoured graft is typically trapezoidal in shape.

The sutures from the 4 anchors are then sequentially retrieved through the lateral cannula. The sutures from the greater tuberosity anchors are passed through their respective holes in the graft. However, the suture limbs from each of the glenoid anchors are individually passed 2 mm anterior and 2 mm posterior to their respective marks on the graft with an antegrade suture passer (Figure 3). It is important to have an assistant apply tension to each of the sutures after they are passed through the graft to decrease the chance of crossing and tangling the sutures.

The eyelets of the medial anchors are utilized as pulleys to deliver the dermal allograft into the shoulder. One suture limb from each of the glenoid anchors is tied to the other over a switching stick (Figure 4A). The 2 remaining (untied) suture limbs are then pulled, which introduces the graft to the orifice of the cannula (Figure 4B). A tissue grasper is then used to fold the dermal allograft along its long axis and introduce the graft into the joint (Figure 4C). Once the medial portion of the graft is positioned onto the superior glenoid the 2 remaining (untied) suture limbs are tied to each other as a static knot in the subacromial space (Figure 4D).

The redundancy in the suture tapes can be removed by sequentially sliding a retriever down each suture and tensioning the suture as the nose of the instrument pushes the dermal graft down to the tuberosity bone bed. The suture tapes are crisscrossed and secured laterally with 2 additional knotless threaded anchors (Figure 5). One may also place cinch stitches at the anterolateral and posterolateral corners of the graft that are incorporated into the lateral anchors. These sutures can be useful for pulling the graft back out of the subacromial space in the event of any suture tangles, and can be used for controlling the lateral aspect of the graft during lateral anchor placement.

 

 

At this point in the procedure, additional glenoid anchors can be placed both anterior and posterior to the superior glenoid anchors if additional glenoid fixation is desired. Finally, 2 to 3 side-to-side sutures are placed posteriorly attaching the anterior aspect of the infraspinatus to the posterior aspect of the dermal allograft (Figures 6A-6C). If rotator interval tissue (comma tissue) is present, anterior side-to-side sutures may be placed. However, we do not recommend placing anterior side-to-side sutures directly from the dermal allograft to the subscapularis as this may deform the graft, over- constrain the shoulder, and restrict motion.

Discussion

Reconstruction of the superior capsule has been shown to restore the normal restraint to superior translation of the humeral head and reestablish a stable fulcrum at the glenohumeral joint.⁵ It should be mentioned that we do not perform the SCR in patients with advanced glenohumeral arthritis. The short-term results of this novel procedure have been encouraging, including our own series of patients, in which most patients have had a significant reduction in pain, improvement in function, and very few complications (P. J. Denard, MD, S. S. Burkhart, MD, P. C. Brady, MD, J. Tokish, MD, C. R. Adams, MD, unpublished data, May 2016).

The early success of this procedure suggests that a robust superior capsule is necessary, in addition to functional muscle-tendon units, to restore the stable fulcrum and force couples that are necessary for normal shoulder function. Perhaps we have not paid enough attention to the integrity of the superior capsule in the past. In cases of revision cuff repair, we pay special attention to the quality of the capsular layer deep to the cuff tendon. If the capsule is poor quality, we sometimes reconstruct the capsule with a dermal allograft (SCR) and then do a rotator cuff repair (partial or complete) over the top of the SCR to maintain the normal anatomic deep to superficial layering of the capsule and rotator cuff.

We are very conservative with our postoperative rehabilitation program after a SCR. We know that the rate of stiffness with a conservative program after an arthroscopic rotator cuff repair, even in the revision setting, is very low.⁶ Furthermore, both basic science on healing of soft tissue to bone and radiographic analysis of healing after postoperative rotator cuff repairs support a slow rehabilitation program.^7,8 A canine model specifically evaluating acellular dermal allografts in the shoulder suggests that these grafts undergo significant remodeling and become weaker before they get stronger.⁹ We would rather err on the side of healing of the SCR with potentially a slight increase in the rate of shoulder stiffness than to regain early motion at the expense of graft failure. Therefore, we have the patient wear a sling with no shoulder motion for 6 weeks. Passive motion is started at 6 weeks postoperative and strengthening is delayed until 12 to 16 weeks postoperative.