Arthroplasty/Joint Replacement

ABSTRACT

It has been suggested that the utilization of joint arthroplasty in patients with rheumatoid arthritis (RA) is decreasing; however, this observation is largely based upon evidence pertaining to lower-extremity joint arthroplasty. It remains unknown if these observed trends also hold true for shoulder arthroplasty. The purpose of this study is to utilize a nationally representative population database in the US to identify trends in the utilization of shoulder arthroplasty among patients with RA. Secondarily, we sought to determine the rate of early adverse events, length of stay, and hospitalization costs associated with RA patients undergoing shoulder arthroplasty and to compare these outcomes to those of patients without a diagnosis of RA undergoing shoulder arthroplasty. Using a large population database in the US, we determined the annual rates of shoulder arthroplasty (overall and individual) in RA patients between 2002 and 2011. Early adverse events, length of stay, and hospitalization costs were determined and compared with those of non-RA patients undergoing shoulder arthroplasty. Overall, we identified 332,593 patients who underwent shoulder arthroplasty between 2002 and 2011, of whom 17,883 patients (5.4%) had a diagnosis of RA. Over the study period, there was a significant increase in the utilization of shoulder arthroplasty in RA patients, particularly total shoulder arthroplasty. Over the same period, there was a significant increase in the number of RA patients who underwent shoulder arthroplasty with a diagnosis of rotator cuff disease. There were no significant differences in adverse events or mean hospitalization costs between RA and non-RA patients. Non-RA patients had a significantly shorter length of stay; however, the difference did not appear to be clinically significant. In conclusion, the utilization of shoulder arthroplasty in patients with RA significantly increased from 2002 to 2011, which may partly reflect a trend toward management of rotator cuff disease with arthroplasty rather than repair.

Continue to: It has been suggested...

It has been suggested that the utilization of total joint arthroplasty (TJA) in patients with rheumatoid arthritis (RA) is decreasing over time;¹ however, this observation is largely based upon evidence pertaining to lower extremity TJA.² It remains unknown if these observed trends also hold true for shoulder arthroplasty, whereby the utilization of shoulder arthroplasty in RA patients is not limited to the management of end-stage inflammatory arthropathy. In this study, we used a nationally representative population database in the US to identify trends in the utilization of shoulder arthroplasty among patients with RA. As a secondary objective, we sought to determine the rate of early adverse events, length of stay, and hospitalization costs associated with RA patients undergoing shoulder arthroplasty and compare these outcomes to those of patients without a diagnosis of RA undergoing shoulder arthroplasty. We hypothesize that the utilization of shoulder arthroplasty in RA patients would be decreasing, but adverse events, length of stay, and hospitalization costs would not differ between patients with and without RA undergoing shoulder arthroplasty.

METHODS

We conducted a retrospective cohort study using the Healthcare Cost and Utilization Project (HCUP) Nationwide Inpatient Sample (NIS) from 2002 to 2011.³ The NIS comprises a 20% stratified sample of all hospital discharges in the US. The NIS includes information about patient characteristics (age, sex, insurance status, and medical comorbidities) and hospitalization outcomes (adverse events, costs, and length of stay). The NIS allows identification of hospitalizations according to procedures and diagnoses using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes. Given the anonymity of this study, it was exempt from Institutional Review Board ethics approval.

Hospitalizations were selected for the study based on ICD-9-CM procedural codes for hemiarthroplasty (81.81), anatomic total shoulder arthroplasty (TSA) (81.80), and reverse TSA (81.88). These patients were then stratified by an ICD-9-CM diagnosis of RA (714.X). We also utilized ICD-9-CM diagnosis codes to determine the presence of rotator cuff pathology at the time of shoulder arthroplasty (726.13, 727.61, 840.4) and to exclude patients with a history of trauma (812.X, 716.11, 733.8X). In a separate analysis, all patients in the NIS database with an ICD-9-CM diagnosis of RA were identified for each calendar year of the study, and a national estimate of RA patients was generated annually to assess overall and individual utilization rates of shoulder arthroplasty in this population (the national estimate served as the denominator).

Preoperative patient data withdrawn from the NIS included age, sex, insurance status, and medical comorbidities. An Elixhauser Comorbidity Index (ECI) was generated for each patient based on the presence of 29 comorbid conditions. The ECI was chosen because of its capacity to accurately predict mortality and represent the patient burden of comorbidities in similar administrative database studies.^4-6

Early adverse events were also chosen based on ICD-9-CM diagnosis codes (Appendix A), and included the following: death, acute kidney injury, cardiac arrest, thromboembolic event, myocardial infarction, peripheral nerve injury, pneumonia, sepsis, stroke, surgical site infection, urinary tract infection, and wound dehiscence. The overall adverse event rate was defined as the occurrence of ≥1 of the above adverse events in a patient.

Appendix A. ICD-9-CM Codes Corresponding to Postoperative Adverse Events

Abbreviation: ICD-9-CM, International Classification of Diseases, Ninth Revision, Clinical Modification

Length of stay and total hospital charges were available for each patient. Length of stay represents the number of calendar days a patient stayed in the hospital. All hospital charges were converted to hospitalization costs using the HCUP Cost-to-Charge Ratio Files. All hospitalization costs were adjusted for inflation using the US Bureau of Labor statistics yearly inflation calculator to represent charges in the year 2011, which was the final and most recent year in this study.

Continue to: Statistical analysis...

STATISTICAL ANALYSIS

Statistical analyses were conducted using Stata version 13.1 (StataCorp, LP). All analyses took into account the complex survey design of the NIS. Discharge weights, strata, and cluster variables were included to correctly estimate variance and to produce national estimates from the stratified sample. Pearson’s chi-squared test was used to compare age, sex, ECI, and insurance status between RA and non-RA patients undergoing shoulder arthroplasty.

Bivariate and multivariate logistic regressions were subsequently used to compare the rates of adverse events between RA and non-RA patients undergoing shoulder arthroplasty (non-RA cases were used as the reference). Multivariate linear regressions were used to compare hospital length of stay and hospitalization costs between RA and non-RA patients undergoing shoulder arthroplasty. The multivariate regressions were adjusted for baseline differences in age, sex, ECI, and insurance status. Cochran-Armitage tests for trend were used to assess trends over time. All tests were 2-tailed, and the statistical difference was established at a 2-sided α level of 0.05 (P < .05).

RESULTS

Overall, we identified 332,593 patients who underwent shoulder arthroplasty in the US between 2002 and 2011, of which 17,883 patients (5.4%) had a diagnosis of RA. In comparison with non-RA patients undergoing shoulder arthroplasty, patients with RA at the time of shoulder arthroplasty were significantly younger (65.2 ± 12.5 years vs 68.4 ± 11.0 years, P < .001), included a significantly greater proportion of female patients (76.7% vs 53.8%, P < .001), and included a significantly higher proportion of patients with Medicaid insurance (3.6% vs 2.3%, P < .001). There were no significant differences in the mean ECI between patients with and without a diagnosis of RA (Table 1). As depicted in Table 1, there were significant differences in the utilization of specific shoulder arthroplasty types between patients with and without RA, whereby a significantly greater proportion of RA patients underwent hemiarthroplasty (HA) (31.6% vs 29.3%, P = .002) and reverse TSA (7.7% vs 6.6%, P = .002), whereas a significantly greater proportion of non-RA patients underwent anatomic SA (64.0% vs 60.8%, P = .002).

Over the study period from 2002 to 2011, there was a significant increase in the overall utilization of shoulder arthroplasty in RA patients, as indicated by both the absolute number and the proportion of patients with a diagnosis of RA (P < .001) (Table 2, Figure). More specifically, 0.39% of RA patients underwent shoulder arthroplasty in 2002, as compared with 0.58% of RA patients in 2011 (P < .001) (Table 2). With respect to specific arthroplasty types, there was an exponential rise in the utilization of reverse TSA beginning in 2010 and a corresponding decrease in the rates of both HA and anatomic TSA (Table 2, Figure). In addition to changes in shoulder arthroplasty utilization over time among RA patients, we also observed a significant increase in the number of RA patients undergoing shoulder arthroplasty with a corresponding diagnosis of rotator cuff disease (9.7% in 2002 to 15.2% in 2011, P < .001).

Table 2. The Annual Utilization of Shoulder Arthroplasty Among Patients with a Diagnosis of Rheumatoid Arthritis.

^aRate determined as number of RA patients undergoing shoulder arthroplasty compared to the number of patients with an RA diagnosis in the stated calendar year.

Abbreviations: HA, hemiarthroplasty; RA, rheumatoid arthritis; TSA, total shoulder arthroplasty.

Continue to: Among patients with RA...

Among patients with RA undergoing shoulder arthroplasty, the overall rate of early adverse events was 3.12%, of which the most common early adverse events were urinary tract infections (1.8%), acute kidney injury (0.66%), and pneumonia (0.38%) (Table 3). As compared with patients without a diagnosis of RA undergoing shoulder arthroplasty, there were no significant differences in the overall and individual rates of early adverse events (Table 3).

Table 3. A Comparison of Early Adverse Events, Length of Stay, and Cost Between Patients With and Without Rheumatoid Arthritis (RA) Undergoing Shoulder Arthroplasty

^aReported in days. ^bReported in 2011 US dollars, adjusted for inflation.

The mean length of stay following shoulder arthroplasty in RA patients was 2.4 ± 1.6 days, and the mean hospitalization cost was $14,787 ± $7625 (Table 3). As compared with non-RA patients undergoing shoulder arthroplasty, there were no significant differences in the mean hospitalization costs; however, non-RA patients had a significantly shorter length of stay by 0.1 days (P = .002) (Table 3).

DISCUSSION

In this study, we observed that the utilization of shoulder arthroplasty in patients with RA increased significantly in the decade from 2002 to 2011, largely related to a rise in TSA. Interestingly, we also observed a corresponding rise in the proportion of RA patients undergoing shoulder arthroplasty with a diagnosis of rotator cuff disease, and we believe that this may partly account for the recent increase in the use of the reverse TSA in this patient population. Additionally, we found shoulder arthroplasty in RA patients to be safe in the early postoperative period, with no significant increase in cost as compared with patients undergoing shoulder arthroplasty without a diagnosis of RA. Although we did observe a significant increase in length of stay among RA patients as compared with non-RA patients, the absolute difference was only 0.1 days, and given the aforementioned similarities in cost between RA and non-RA patients, we do not believe this difference to be clinically significant.

It has been theorized that the utilization of TJA in RA patients has been decreasing with improvements in medical management; however, this is largely based upon literature pertaining to lower extremity TJA.² On the contrary, past research pertaining to the utilization of shoulder arthroplasty in RA patients has been highly variable. For instance, a Swedish study demonstrated a statistically significant decrease in admissions associated with RA-related upper limb surgery and a stable rate of shoulder arthroplasty between 1998 and 2004.⁷ Similarly, a Finnish study demonstrated that the annual incidence of primary joint arthroplasty in RA patients had declined from 1995 to 2010, with a greater decline for upper-limb arthroplasty as compared with lower-limb arthroplasty.⁸ Despite these European observations, Jain and colleagues⁹ reported an increasing rate of TSA among RA patients in the US between the years 1992 and 2005. In this study, we demonstrate a clear increase in the utilization of shoulder arthroplasty among RA patients between 2002 and 2011. What was most striking about our observation was that the rise in utilization appeared to be driven by an increase in TSA, whereas the utilization of HA decreased over time. This change in practice likely reflects several factors, including the multitude of studies that have demonstrated improved outcomes with anatomic TSA as compared with HA in RA patients.^10-14

Perhaps the most interesting aspect of our data was the recent exponential rise in the utilization of the reverse TSA. Despite improved outcomes following TSA as compared with HA in RA patients, these outcomes all appear to be highly dependent upon the integrity of the rotator cuff.¹⁰ In fact, there is evidence that failure of the rotator cuff could be as high as 75% within 10 years of TSA in patients with RA,¹⁵ which ultimately could jeopardize the long-term durability of the TSA implant in this patient population.¹¹ For this reason, interest in the reverse TSA for the RA patient population has increased since its introduction in the US in 2004;¹⁶ in fact, in RA patients with end-stage inflammatory arthropathy and a damaged rotator cuff, the reverse TSA has demonstrated excellent results.^17-20 Based upon this evidence, it is not surprising that we found an exponential rise in the use of the reverse TSA since 2010, which corresponds to the introduction of an ICD-9 code for this implant.²¹ Prior to 2010, it is likely that many implanted reverse TSAs were coded as TSA, and for this reason, we believe that the observed rise in the utilization of TSA in RA patients prior to 2010 may have been partly fueled by an increase in the use of the reverse TSA. To further support this theory, there was a dramatic decrease in the use of anatomic TSA following 2010, and we believe this was related to increased awareness of the newly introduced reverse TSA code among surgeons.

Another consideration when examining the utilization of shoulder arthroplasty in RA patients is its versatility in managing different disease states, including rotator cuff disease. As has been documented in the literature, outcomes of rotator cuff repair in RA patients are discouraging.²² For this reason, it is reasonable for surgeons and patients with RA to consider alternatives to rotator cuff repair when nonoperative management has failed to provide adequate improvement in symptoms. One alternative may be shoulder arthroplasty, namely the reverse TSA. In this study, we observed a significant increase in the rate of diagnosis of rotator cuff disease among RA patients undergoing shoulder arthroplasty from 2002 to 2011 (9.7% in 2002 to 15.2% in 2011, P < .001), and it is our belief that the simultaneous increase in the diagnosis of rotator cuff disease and use of TSA is not coincidental. More specifically, there is likely an emerging trend among surgeons toward using the reverse TSA to manage rotator cuff tears in the RA population, rather than undertaking a rotator cuff repair that carries a high rate of failure. Going forward, there is a need to not only identify this trend more clearly but to also compare the outcomes between reverse TSA and rotator cuff repair in the management of rotator cuff tears in RA patients.

Continue to: In this study, we observed...

In this study, we observed that RA patients undergoing shoulder arthroplasty were significantly younger than non-RA patients undergoing shoulder arthroplasty. At first, this observation seems to counter recent literature suggesting that the age of patients with inflammatory arthropathy undergoing TJA is increasing over time;¹ however, looking more closely at the data, it becomes clearer that the mean age we report is actually a relative increase as compared with past clinical studies pertaining to RA patients undergoing shoulder arthroplasty (mean ages of 47 years,²³ 55 years,²⁴ 60 years,¹⁰ and 62 years²⁵). On the other hand, the continued existence of an age gap between RA and non-RA patients undergoing shoulder arthroplasty may be the result of several possible phenomena. First, this may reflect issues with patient access to and coverage of expensive biologic antirheumatic medication that would otherwise mitigate disease progression. For instance, the out-of-pocket expense for biologic medication through Medicaid and Medicare is substantial,²⁶ which has direct implications on over two-thirds of our RA cohort. Second, it may be skewed by the proportion of RA patients who have previously been or continue to be poorly managed, enabling disease progression to end-stage arthropathy at a younger age. Ultimately, further investigation is needed to determine the reasons for this continued age disparity.

In comparing RA and non-RA patients undergoing shoulder arthroplasty, we did not find a significant difference in the overall nor the individual rates of early adverse events. This finding appears to be unique, as similar studies pertaining to total knee arthroplasty (TKA) demonstrated a significantly higher incidence of postoperative pneumonia and bleeding requiring transfusion among RA patients as compared with non-RA patients.²⁷ In patients with RA being treated with biologic medication and undergoing shoulder arthroplasty, the frequent concern in the postoperative period is the integrity of the wound and the potential for infection.²⁸ In this study, we did not find a significant difference in the rate of early infection, and although the difference in the rate of early wound dehiscence approached significance, it did not meet the threshold of 0.05 (P = .09). This finding is in keeping with the aforementioned NIS study pertaining to TKA, and we believe that it likely reflects the short duration of follow-up for patients in both studies. Given the nature of the database we utilized, we were only privy to complications that arose during the inpatient hospital stay, and it is likely that the clear majority of patients who develop a postoperative infection or wound dehiscence do so in the postoperative setting following discharge. A second concern regarding postoperative wound complications is the management of biologic medication in the perioperative period, which we cannot determine using this database. Despite all these limitations specific to this database, a past systematic review of reverse TSA in RA patients found a low rate of deep infection after reverse TSA in RA patients (3.3%),¹⁷ which was not higher than that after shoulder arthroplasty performed in non-RA patients.

A final demonstration from this study is that the hospital length of stay was significantly longer for RA patients than non-RA patients undergoing shoulder arthroplasty; however, given that the difference was only 0.1 days, and there was no significant difference in hospitalization cost, we are inclined to believe that statistical significance may not translate into clinical significance in this scenario. Ultimately, we do believe that length of stay is an important consideration in the current healthcare system, and given our finding that shoulder arthroplasty in the RA patient is safe in the early postoperative period, that a prolonged postoperative hospitalization is not warranted on the sole basis of a patient’s history of RA.

As with all studies using data from a search of an administrative database, such as the NIS database, this study has limitations. First, this type of research is limited by the reliability of both diagnosis and procedural coding. Although the NIS database has demonstrated high reliability,³ it is still possible that events may have been miscoded. Second, the tracking period for adverse events is limited to the inpatient hospital stay, which may be too short to detect certain postoperative complications. As such, the rates we report are likely underestimates of the true incidence of these complications, but this is true for both the RA and non-RA populations. Third, the comparisons we draw between RA and non-RA patients are limited to the scope of the NIS database and the available data; as such, we could not draw comparisons between preoperative disease stage, intraoperative findings, and postoperative course following hospital discharge. Lastly, our data are limited to a distinct period between 2002 and 2011 and may not reflect current practice. Ultimately, our findings may underestimate current trends in shoulder arthroplasty utilization among RA patients, particularly for the reverse TSA.

CONCLUSION

In this study, we found that the utilization of shoulder arthroplasty in patients with RA increased significantly from 2002 to 2011, largely related to a rise in the utilization of TSA. Similarly, we observed a rise in the proportion of RA patients undergoing shoulder arthroplasty with a corresponding diagnosis of rotator cuff disease, and we believe the increased utilization of shoulder arthroplasty among RA patients resulted from management of both end-stage inflammatory arthropathy and rotator cuff disease. Although we did not find a significant difference between RA and non-RA patients in the rates of early adverse events and overall hospitalization costs following shoulder arthroplasty, length of stay was significantly longer among RA patients; however, the absolute difference does not appear to be clinically significant.

ABSTRACT

It has been suggested that the utilization of joint arthroplasty in patients with rheumatoid arthritis (RA) is decreasing; however, this observation is largely based upon evidence pertaining to lower-extremity joint arthroplasty. It remains unknown if these observed trends also hold true for shoulder arthroplasty. The purpose of this study is to utilize a nationally representative population database in the US to identify trends in the utilization of shoulder arthroplasty among patients with RA. Secondarily, we sought to determine the rate of early adverse events, length of stay, and hospitalization costs associated with RA patients undergoing shoulder arthroplasty and to compare these outcomes to those of patients without a diagnosis of RA undergoing shoulder arthroplasty. Using a large population database in the US, we determined the annual rates of shoulder arthroplasty (overall and individual) in RA patients between 2002 and 2011. Early adverse events, length of stay, and hospitalization costs were determined and compared with those of non-RA patients undergoing shoulder arthroplasty. Overall, we identified 332,593 patients who underwent shoulder arthroplasty between 2002 and 2011, of whom 17,883 patients (5.4%) had a diagnosis of RA. Over the study period, there was a significant increase in the utilization of shoulder arthroplasty in RA patients, particularly total shoulder arthroplasty. Over the same period, there was a significant increase in the number of RA patients who underwent shoulder arthroplasty with a diagnosis of rotator cuff disease. There were no significant differences in adverse events or mean hospitalization costs between RA and non-RA patients. Non-RA patients had a significantly shorter length of stay; however, the difference did not appear to be clinically significant. In conclusion, the utilization of shoulder arthroplasty in patients with RA significantly increased from 2002 to 2011, which may partly reflect a trend toward management of rotator cuff disease with arthroplasty rather than repair.

Continue to: It has been suggested...

It has been suggested that the utilization of total joint arthroplasty (TJA) in patients with rheumatoid arthritis (RA) is decreasing over time;¹ however, this observation is largely based upon evidence pertaining to lower extremity TJA.² It remains unknown if these observed trends also hold true for shoulder arthroplasty, whereby the utilization of shoulder arthroplasty in RA patients is not limited to the management of end-stage inflammatory arthropathy. In this study, we used a nationally representative population database in the US to identify trends in the utilization of shoulder arthroplasty among patients with RA. As a secondary objective, we sought to determine the rate of early adverse events, length of stay, and hospitalization costs associated with RA patients undergoing shoulder arthroplasty and compare these outcomes to those of patients without a diagnosis of RA undergoing shoulder arthroplasty. We hypothesize that the utilization of shoulder arthroplasty in RA patients would be decreasing, but adverse events, length of stay, and hospitalization costs would not differ between patients with and without RA undergoing shoulder arthroplasty.

METHODS

We conducted a retrospective cohort study using the Healthcare Cost and Utilization Project (HCUP) Nationwide Inpatient Sample (NIS) from 2002 to 2011.³ The NIS comprises a 20% stratified sample of all hospital discharges in the US. The NIS includes information about patient characteristics (age, sex, insurance status, and medical comorbidities) and hospitalization outcomes (adverse events, costs, and length of stay). The NIS allows identification of hospitalizations according to procedures and diagnoses using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes. Given the anonymity of this study, it was exempt from Institutional Review Board ethics approval.

Hospitalizations were selected for the study based on ICD-9-CM procedural codes for hemiarthroplasty (81.81), anatomic total shoulder arthroplasty (TSA) (81.80), and reverse TSA (81.88). These patients were then stratified by an ICD-9-CM diagnosis of RA (714.X). We also utilized ICD-9-CM diagnosis codes to determine the presence of rotator cuff pathology at the time of shoulder arthroplasty (726.13, 727.61, 840.4) and to exclude patients with a history of trauma (812.X, 716.11, 733.8X). In a separate analysis, all patients in the NIS database with an ICD-9-CM diagnosis of RA were identified for each calendar year of the study, and a national estimate of RA patients was generated annually to assess overall and individual utilization rates of shoulder arthroplasty in this population (the national estimate served as the denominator).

Preoperative patient data withdrawn from the NIS included age, sex, insurance status, and medical comorbidities. An Elixhauser Comorbidity Index (ECI) was generated for each patient based on the presence of 29 comorbid conditions. The ECI was chosen because of its capacity to accurately predict mortality and represent the patient burden of comorbidities in similar administrative database studies.^4-6

Early adverse events were also chosen based on ICD-9-CM diagnosis codes (Appendix A), and included the following: death, acute kidney injury, cardiac arrest, thromboembolic event, myocardial infarction, peripheral nerve injury, pneumonia, sepsis, stroke, surgical site infection, urinary tract infection, and wound dehiscence. The overall adverse event rate was defined as the occurrence of ≥1 of the above adverse events in a patient.

Appendix A. ICD-9-CM Codes Corresponding to Postoperative Adverse Events

Abbreviation: ICD-9-CM, International Classification of Diseases, Ninth Revision, Clinical Modification

Length of stay and total hospital charges were available for each patient. Length of stay represents the number of calendar days a patient stayed in the hospital. All hospital charges were converted to hospitalization costs using the HCUP Cost-to-Charge Ratio Files. All hospitalization costs were adjusted for inflation using the US Bureau of Labor statistics yearly inflation calculator to represent charges in the year 2011, which was the final and most recent year in this study.

Continue to: Statistical analysis...

STATISTICAL ANALYSIS

Statistical analyses were conducted using Stata version 13.1 (StataCorp, LP). All analyses took into account the complex survey design of the NIS. Discharge weights, strata, and cluster variables were included to correctly estimate variance and to produce national estimates from the stratified sample. Pearson’s chi-squared test was used to compare age, sex, ECI, and insurance status between RA and non-RA patients undergoing shoulder arthroplasty.

Bivariate and multivariate logistic regressions were subsequently used to compare the rates of adverse events between RA and non-RA patients undergoing shoulder arthroplasty (non-RA cases were used as the reference). Multivariate linear regressions were used to compare hospital length of stay and hospitalization costs between RA and non-RA patients undergoing shoulder arthroplasty. The multivariate regressions were adjusted for baseline differences in age, sex, ECI, and insurance status. Cochran-Armitage tests for trend were used to assess trends over time. All tests were 2-tailed, and the statistical difference was established at a 2-sided α level of 0.05 (P < .05).

RESULTS

Overall, we identified 332,593 patients who underwent shoulder arthroplasty in the US between 2002 and 2011, of which 17,883 patients (5.4%) had a diagnosis of RA. In comparison with non-RA patients undergoing shoulder arthroplasty, patients with RA at the time of shoulder arthroplasty were significantly younger (65.2 ± 12.5 years vs 68.4 ± 11.0 years, P < .001), included a significantly greater proportion of female patients (76.7% vs 53.8%, P < .001), and included a significantly higher proportion of patients with Medicaid insurance (3.6% vs 2.3%, P < .001). There were no significant differences in the mean ECI between patients with and without a diagnosis of RA (Table 1). As depicted in Table 1, there were significant differences in the utilization of specific shoulder arthroplasty types between patients with and without RA, whereby a significantly greater proportion of RA patients underwent hemiarthroplasty (HA) (31.6% vs 29.3%, P = .002) and reverse TSA (7.7% vs 6.6%, P = .002), whereas a significantly greater proportion of non-RA patients underwent anatomic SA (64.0% vs 60.8%, P = .002).

Over the study period from 2002 to 2011, there was a significant increase in the overall utilization of shoulder arthroplasty in RA patients, as indicated by both the absolute number and the proportion of patients with a diagnosis of RA (P < .001) (Table 2, Figure). More specifically, 0.39% of RA patients underwent shoulder arthroplasty in 2002, as compared with 0.58% of RA patients in 2011 (P < .001) (Table 2). With respect to specific arthroplasty types, there was an exponential rise in the utilization of reverse TSA beginning in 2010 and a corresponding decrease in the rates of both HA and anatomic TSA (Table 2, Figure). In addition to changes in shoulder arthroplasty utilization over time among RA patients, we also observed a significant increase in the number of RA patients undergoing shoulder arthroplasty with a corresponding diagnosis of rotator cuff disease (9.7% in 2002 to 15.2% in 2011, P < .001).

Table 2. The Annual Utilization of Shoulder Arthroplasty Among Patients with a Diagnosis of Rheumatoid Arthritis.

^aRate determined as number of RA patients undergoing shoulder arthroplasty compared to the number of patients with an RA diagnosis in the stated calendar year.

Abbreviations: HA, hemiarthroplasty; RA, rheumatoid arthritis; TSA, total shoulder arthroplasty.

Continue to: Among patients with RA...

Among patients with RA undergoing shoulder arthroplasty, the overall rate of early adverse events was 3.12%, of which the most common early adverse events were urinary tract infections (1.8%), acute kidney injury (0.66%), and pneumonia (0.38%) (Table 3). As compared with patients without a diagnosis of RA undergoing shoulder arthroplasty, there were no significant differences in the overall and individual rates of early adverse events (Table 3).

Table 3. A Comparison of Early Adverse Events, Length of Stay, and Cost Between Patients With and Without Rheumatoid Arthritis (RA) Undergoing Shoulder Arthroplasty

^aReported in days. ^bReported in 2011 US dollars, adjusted for inflation.

The mean length of stay following shoulder arthroplasty in RA patients was 2.4 ± 1.6 days, and the mean hospitalization cost was $14,787 ± $7625 (Table 3). As compared with non-RA patients undergoing shoulder arthroplasty, there were no significant differences in the mean hospitalization costs; however, non-RA patients had a significantly shorter length of stay by 0.1 days (P = .002) (Table 3).

DISCUSSION

In this study, we observed that the utilization of shoulder arthroplasty in patients with RA increased significantly in the decade from 2002 to 2011, largely related to a rise in TSA. Interestingly, we also observed a corresponding rise in the proportion of RA patients undergoing shoulder arthroplasty with a diagnosis of rotator cuff disease, and we believe that this may partly account for the recent increase in the use of the reverse TSA in this patient population. Additionally, we found shoulder arthroplasty in RA patients to be safe in the early postoperative period, with no significant increase in cost as compared with patients undergoing shoulder arthroplasty without a diagnosis of RA. Although we did observe a significant increase in length of stay among RA patients as compared with non-RA patients, the absolute difference was only 0.1 days, and given the aforementioned similarities in cost between RA and non-RA patients, we do not believe this difference to be clinically significant.

It has been theorized that the utilization of TJA in RA patients has been decreasing with improvements in medical management; however, this is largely based upon literature pertaining to lower extremity TJA.² On the contrary, past research pertaining to the utilization of shoulder arthroplasty in RA patients has been highly variable. For instance, a Swedish study demonstrated a statistically significant decrease in admissions associated with RA-related upper limb surgery and a stable rate of shoulder arthroplasty between 1998 and 2004.⁷ Similarly, a Finnish study demonstrated that the annual incidence of primary joint arthroplasty in RA patients had declined from 1995 to 2010, with a greater decline for upper-limb arthroplasty as compared with lower-limb arthroplasty.⁸ Despite these European observations, Jain and colleagues⁹ reported an increasing rate of TSA among RA patients in the US between the years 1992 and 2005. In this study, we demonstrate a clear increase in the utilization of shoulder arthroplasty among RA patients between 2002 and 2011. What was most striking about our observation was that the rise in utilization appeared to be driven by an increase in TSA, whereas the utilization of HA decreased over time. This change in practice likely reflects several factors, including the multitude of studies that have demonstrated improved outcomes with anatomic TSA as compared with HA in RA patients.^10-14

Perhaps the most interesting aspect of our data was the recent exponential rise in the utilization of the reverse TSA. Despite improved outcomes following TSA as compared with HA in RA patients, these outcomes all appear to be highly dependent upon the integrity of the rotator cuff.¹⁰ In fact, there is evidence that failure of the rotator cuff could be as high as 75% within 10 years of TSA in patients with RA,¹⁵ which ultimately could jeopardize the long-term durability of the TSA implant in this patient population.¹¹ For this reason, interest in the reverse TSA for the RA patient population has increased since its introduction in the US in 2004;¹⁶ in fact, in RA patients with end-stage inflammatory arthropathy and a damaged rotator cuff, the reverse TSA has demonstrated excellent results.^17-20 Based upon this evidence, it is not surprising that we found an exponential rise in the use of the reverse TSA since 2010, which corresponds to the introduction of an ICD-9 code for this implant.²¹ Prior to 2010, it is likely that many implanted reverse TSAs were coded as TSA, and for this reason, we believe that the observed rise in the utilization of TSA in RA patients prior to 2010 may have been partly fueled by an increase in the use of the reverse TSA. To further support this theory, there was a dramatic decrease in the use of anatomic TSA following 2010, and we believe this was related to increased awareness of the newly introduced reverse TSA code among surgeons.

Another consideration when examining the utilization of shoulder arthroplasty in RA patients is its versatility in managing different disease states, including rotator cuff disease. As has been documented in the literature, outcomes of rotator cuff repair in RA patients are discouraging.²² For this reason, it is reasonable for surgeons and patients with RA to consider alternatives to rotator cuff repair when nonoperative management has failed to provide adequate improvement in symptoms. One alternative may be shoulder arthroplasty, namely the reverse TSA. In this study, we observed a significant increase in the rate of diagnosis of rotator cuff disease among RA patients undergoing shoulder arthroplasty from 2002 to 2011 (9.7% in 2002 to 15.2% in 2011, P < .001), and it is our belief that the simultaneous increase in the diagnosis of rotator cuff disease and use of TSA is not coincidental. More specifically, there is likely an emerging trend among surgeons toward using the reverse TSA to manage rotator cuff tears in the RA population, rather than undertaking a rotator cuff repair that carries a high rate of failure. Going forward, there is a need to not only identify this trend more clearly but to also compare the outcomes between reverse TSA and rotator cuff repair in the management of rotator cuff tears in RA patients.

Continue to: In this study, we observed...

In this study, we observed that RA patients undergoing shoulder arthroplasty were significantly younger than non-RA patients undergoing shoulder arthroplasty. At first, this observation seems to counter recent literature suggesting that the age of patients with inflammatory arthropathy undergoing TJA is increasing over time;¹ however, looking more closely at the data, it becomes clearer that the mean age we report is actually a relative increase as compared with past clinical studies pertaining to RA patients undergoing shoulder arthroplasty (mean ages of 47 years,²³ 55 years,²⁴ 60 years,¹⁰ and 62 years²⁵). On the other hand, the continued existence of an age gap between RA and non-RA patients undergoing shoulder arthroplasty may be the result of several possible phenomena. First, this may reflect issues with patient access to and coverage of expensive biologic antirheumatic medication that would otherwise mitigate disease progression. For instance, the out-of-pocket expense for biologic medication through Medicaid and Medicare is substantial,²⁶ which has direct implications on over two-thirds of our RA cohort. Second, it may be skewed by the proportion of RA patients who have previously been or continue to be poorly managed, enabling disease progression to end-stage arthropathy at a younger age. Ultimately, further investigation is needed to determine the reasons for this continued age disparity.

In comparing RA and non-RA patients undergoing shoulder arthroplasty, we did not find a significant difference in the overall nor the individual rates of early adverse events. This finding appears to be unique, as similar studies pertaining to total knee arthroplasty (TKA) demonstrated a significantly higher incidence of postoperative pneumonia and bleeding requiring transfusion among RA patients as compared with non-RA patients.²⁷ In patients with RA being treated with biologic medication and undergoing shoulder arthroplasty, the frequent concern in the postoperative period is the integrity of the wound and the potential for infection.²⁸ In this study, we did not find a significant difference in the rate of early infection, and although the difference in the rate of early wound dehiscence approached significance, it did not meet the threshold of 0.05 (P = .09). This finding is in keeping with the aforementioned NIS study pertaining to TKA, and we believe that it likely reflects the short duration of follow-up for patients in both studies. Given the nature of the database we utilized, we were only privy to complications that arose during the inpatient hospital stay, and it is likely that the clear majority of patients who develop a postoperative infection or wound dehiscence do so in the postoperative setting following discharge. A second concern regarding postoperative wound complications is the management of biologic medication in the perioperative period, which we cannot determine using this database. Despite all these limitations specific to this database, a past systematic review of reverse TSA in RA patients found a low rate of deep infection after reverse TSA in RA patients (3.3%),¹⁷ which was not higher than that after shoulder arthroplasty performed in non-RA patients.

A final demonstration from this study is that the hospital length of stay was significantly longer for RA patients than non-RA patients undergoing shoulder arthroplasty; however, given that the difference was only 0.1 days, and there was no significant difference in hospitalization cost, we are inclined to believe that statistical significance may not translate into clinical significance in this scenario. Ultimately, we do believe that length of stay is an important consideration in the current healthcare system, and given our finding that shoulder arthroplasty in the RA patient is safe in the early postoperative period, that a prolonged postoperative hospitalization is not warranted on the sole basis of a patient’s history of RA.

As with all studies using data from a search of an administrative database, such as the NIS database, this study has limitations. First, this type of research is limited by the reliability of both diagnosis and procedural coding. Although the NIS database has demonstrated high reliability,³ it is still possible that events may have been miscoded. Second, the tracking period for adverse events is limited to the inpatient hospital stay, which may be too short to detect certain postoperative complications. As such, the rates we report are likely underestimates of the true incidence of these complications, but this is true for both the RA and non-RA populations. Third, the comparisons we draw between RA and non-RA patients are limited to the scope of the NIS database and the available data; as such, we could not draw comparisons between preoperative disease stage, intraoperative findings, and postoperative course following hospital discharge. Lastly, our data are limited to a distinct period between 2002 and 2011 and may not reflect current practice. Ultimately, our findings may underestimate current trends in shoulder arthroplasty utilization among RA patients, particularly for the reverse TSA.

CONCLUSION

In this study, we found that the utilization of shoulder arthroplasty in patients with RA increased significantly from 2002 to 2011, largely related to a rise in the utilization of TSA. Similarly, we observed a rise in the proportion of RA patients undergoing shoulder arthroplasty with a corresponding diagnosis of rotator cuff disease, and we believe the increased utilization of shoulder arthroplasty among RA patients resulted from management of both end-stage inflammatory arthropathy and rotator cuff disease. Although we did not find a significant difference between RA and non-RA patients in the rates of early adverse events and overall hospitalization costs following shoulder arthroplasty, length of stay was significantly longer among RA patients; however, the absolute difference does not appear to be clinically significant.

ABSTRACT

It has been suggested that the utilization of joint arthroplasty in patients with rheumatoid arthritis (RA) is decreasing; however, this observation is largely based upon evidence pertaining to lower-extremity joint arthroplasty. It remains unknown if these observed trends also hold true for shoulder arthroplasty. The purpose of this study is to utilize a nationally representative population database in the US to identify trends in the utilization of shoulder arthroplasty among patients with RA. Secondarily, we sought to determine the rate of early adverse events, length of stay, and hospitalization costs associated with RA patients undergoing shoulder arthroplasty and to compare these outcomes to those of patients without a diagnosis of RA undergoing shoulder arthroplasty. Using a large population database in the US, we determined the annual rates of shoulder arthroplasty (overall and individual) in RA patients between 2002 and 2011. Early adverse events, length of stay, and hospitalization costs were determined and compared with those of non-RA patients undergoing shoulder arthroplasty. Overall, we identified 332,593 patients who underwent shoulder arthroplasty between 2002 and 2011, of whom 17,883 patients (5.4%) had a diagnosis of RA. Over the study period, there was a significant increase in the utilization of shoulder arthroplasty in RA patients, particularly total shoulder arthroplasty. Over the same period, there was a significant increase in the number of RA patients who underwent shoulder arthroplasty with a diagnosis of rotator cuff disease. There were no significant differences in adverse events or mean hospitalization costs between RA and non-RA patients. Non-RA patients had a significantly shorter length of stay; however, the difference did not appear to be clinically significant. In conclusion, the utilization of shoulder arthroplasty in patients with RA significantly increased from 2002 to 2011, which may partly reflect a trend toward management of rotator cuff disease with arthroplasty rather than repair.

Continue to: It has been suggested...

It has been suggested that the utilization of total joint arthroplasty (TJA) in patients with rheumatoid arthritis (RA) is decreasing over time;¹ however, this observation is largely based upon evidence pertaining to lower extremity TJA.² It remains unknown if these observed trends also hold true for shoulder arthroplasty, whereby the utilization of shoulder arthroplasty in RA patients is not limited to the management of end-stage inflammatory arthropathy. In this study, we used a nationally representative population database in the US to identify trends in the utilization of shoulder arthroplasty among patients with RA. As a secondary objective, we sought to determine the rate of early adverse events, length of stay, and hospitalization costs associated with RA patients undergoing shoulder arthroplasty and compare these outcomes to those of patients without a diagnosis of RA undergoing shoulder arthroplasty. We hypothesize that the utilization of shoulder arthroplasty in RA patients would be decreasing, but adverse events, length of stay, and hospitalization costs would not differ between patients with and without RA undergoing shoulder arthroplasty.

METHODS

We conducted a retrospective cohort study using the Healthcare Cost and Utilization Project (HCUP) Nationwide Inpatient Sample (NIS) from 2002 to 2011.³ The NIS comprises a 20% stratified sample of all hospital discharges in the US. The NIS includes information about patient characteristics (age, sex, insurance status, and medical comorbidities) and hospitalization outcomes (adverse events, costs, and length of stay). The NIS allows identification of hospitalizations according to procedures and diagnoses using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes. Given the anonymity of this study, it was exempt from Institutional Review Board ethics approval.

Hospitalizations were selected for the study based on ICD-9-CM procedural codes for hemiarthroplasty (81.81), anatomic total shoulder arthroplasty (TSA) (81.80), and reverse TSA (81.88). These patients were then stratified by an ICD-9-CM diagnosis of RA (714.X). We also utilized ICD-9-CM diagnosis codes to determine the presence of rotator cuff pathology at the time of shoulder arthroplasty (726.13, 727.61, 840.4) and to exclude patients with a history of trauma (812.X, 716.11, 733.8X). In a separate analysis, all patients in the NIS database with an ICD-9-CM diagnosis of RA were identified for each calendar year of the study, and a national estimate of RA patients was generated annually to assess overall and individual utilization rates of shoulder arthroplasty in this population (the national estimate served as the denominator).

Preoperative patient data withdrawn from the NIS included age, sex, insurance status, and medical comorbidities. An Elixhauser Comorbidity Index (ECI) was generated for each patient based on the presence of 29 comorbid conditions. The ECI was chosen because of its capacity to accurately predict mortality and represent the patient burden of comorbidities in similar administrative database studies.^4-6

Early adverse events were also chosen based on ICD-9-CM diagnosis codes (Appendix A), and included the following: death, acute kidney injury, cardiac arrest, thromboembolic event, myocardial infarction, peripheral nerve injury, pneumonia, sepsis, stroke, surgical site infection, urinary tract infection, and wound dehiscence. The overall adverse event rate was defined as the occurrence of ≥1 of the above adverse events in a patient.

Appendix A. ICD-9-CM Codes Corresponding to Postoperative Adverse Events

Abbreviation: ICD-9-CM, International Classification of Diseases, Ninth Revision, Clinical Modification

Length of stay and total hospital charges were available for each patient. Length of stay represents the number of calendar days a patient stayed in the hospital. All hospital charges were converted to hospitalization costs using the HCUP Cost-to-Charge Ratio Files. All hospitalization costs were adjusted for inflation using the US Bureau of Labor statistics yearly inflation calculator to represent charges in the year 2011, which was the final and most recent year in this study.

Continue to: Statistical analysis...

STATISTICAL ANALYSIS

Statistical analyses were conducted using Stata version 13.1 (StataCorp, LP). All analyses took into account the complex survey design of the NIS. Discharge weights, strata, and cluster variables were included to correctly estimate variance and to produce national estimates from the stratified sample. Pearson’s chi-squared test was used to compare age, sex, ECI, and insurance status between RA and non-RA patients undergoing shoulder arthroplasty.

Bivariate and multivariate logistic regressions were subsequently used to compare the rates of adverse events between RA and non-RA patients undergoing shoulder arthroplasty (non-RA cases were used as the reference). Multivariate linear regressions were used to compare hospital length of stay and hospitalization costs between RA and non-RA patients undergoing shoulder arthroplasty. The multivariate regressions were adjusted for baseline differences in age, sex, ECI, and insurance status. Cochran-Armitage tests for trend were used to assess trends over time. All tests were 2-tailed, and the statistical difference was established at a 2-sided α level of 0.05 (P < .05).

RESULTS

Overall, we identified 332,593 patients who underwent shoulder arthroplasty in the US between 2002 and 2011, of which 17,883 patients (5.4%) had a diagnosis of RA. In comparison with non-RA patients undergoing shoulder arthroplasty, patients with RA at the time of shoulder arthroplasty were significantly younger (65.2 ± 12.5 years vs 68.4 ± 11.0 years, P < .001), included a significantly greater proportion of female patients (76.7% vs 53.8%, P < .001), and included a significantly higher proportion of patients with Medicaid insurance (3.6% vs 2.3%, P < .001). There were no significant differences in the mean ECI between patients with and without a diagnosis of RA (Table 1). As depicted in Table 1, there were significant differences in the utilization of specific shoulder arthroplasty types between patients with and without RA, whereby a significantly greater proportion of RA patients underwent hemiarthroplasty (HA) (31.6% vs 29.3%, P = .002) and reverse TSA (7.7% vs 6.6%, P = .002), whereas a significantly greater proportion of non-RA patients underwent anatomic SA (64.0% vs 60.8%, P = .002).

Over the study period from 2002 to 2011, there was a significant increase in the overall utilization of shoulder arthroplasty in RA patients, as indicated by both the absolute number and the proportion of patients with a diagnosis of RA (P < .001) (Table 2, Figure). More specifically, 0.39% of RA patients underwent shoulder arthroplasty in 2002, as compared with 0.58% of RA patients in 2011 (P < .001) (Table 2). With respect to specific arthroplasty types, there was an exponential rise in the utilization of reverse TSA beginning in 2010 and a corresponding decrease in the rates of both HA and anatomic TSA (Table 2, Figure). In addition to changes in shoulder arthroplasty utilization over time among RA patients, we also observed a significant increase in the number of RA patients undergoing shoulder arthroplasty with a corresponding diagnosis of rotator cuff disease (9.7% in 2002 to 15.2% in 2011, P < .001).

Table 2. The Annual Utilization of Shoulder Arthroplasty Among Patients with a Diagnosis of Rheumatoid Arthritis.

^aRate determined as number of RA patients undergoing shoulder arthroplasty compared to the number of patients with an RA diagnosis in the stated calendar year.

Abbreviations: HA, hemiarthroplasty; RA, rheumatoid arthritis; TSA, total shoulder arthroplasty.

Continue to: Among patients with RA...

Among patients with RA undergoing shoulder arthroplasty, the overall rate of early adverse events was 3.12%, of which the most common early adverse events were urinary tract infections (1.8%), acute kidney injury (0.66%), and pneumonia (0.38%) (Table 3). As compared with patients without a diagnosis of RA undergoing shoulder arthroplasty, there were no significant differences in the overall and individual rates of early adverse events (Table 3).

Table 3. A Comparison of Early Adverse Events, Length of Stay, and Cost Between Patients With and Without Rheumatoid Arthritis (RA) Undergoing Shoulder Arthroplasty

^aReported in days. ^bReported in 2011 US dollars, adjusted for inflation.

The mean length of stay following shoulder arthroplasty in RA patients was 2.4 ± 1.6 days, and the mean hospitalization cost was $14,787 ± $7625 (Table 3). As compared with non-RA patients undergoing shoulder arthroplasty, there were no significant differences in the mean hospitalization costs; however, non-RA patients had a significantly shorter length of stay by 0.1 days (P = .002) (Table 3).

DISCUSSION

In this study, we observed that the utilization of shoulder arthroplasty in patients with RA increased significantly in the decade from 2002 to 2011, largely related to a rise in TSA. Interestingly, we also observed a corresponding rise in the proportion of RA patients undergoing shoulder arthroplasty with a diagnosis of rotator cuff disease, and we believe that this may partly account for the recent increase in the use of the reverse TSA in this patient population. Additionally, we found shoulder arthroplasty in RA patients to be safe in the early postoperative period, with no significant increase in cost as compared with patients undergoing shoulder arthroplasty without a diagnosis of RA. Although we did observe a significant increase in length of stay among RA patients as compared with non-RA patients, the absolute difference was only 0.1 days, and given the aforementioned similarities in cost between RA and non-RA patients, we do not believe this difference to be clinically significant.

It has been theorized that the utilization of TJA in RA patients has been decreasing with improvements in medical management; however, this is largely based upon literature pertaining to lower extremity TJA.² On the contrary, past research pertaining to the utilization of shoulder arthroplasty in RA patients has been highly variable. For instance, a Swedish study demonstrated a statistically significant decrease in admissions associated with RA-related upper limb surgery and a stable rate of shoulder arthroplasty between 1998 and 2004.⁷ Similarly, a Finnish study demonstrated that the annual incidence of primary joint arthroplasty in RA patients had declined from 1995 to 2010, with a greater decline for upper-limb arthroplasty as compared with lower-limb arthroplasty.⁸ Despite these European observations, Jain and colleagues⁹ reported an increasing rate of TSA among RA patients in the US between the years 1992 and 2005. In this study, we demonstrate a clear increase in the utilization of shoulder arthroplasty among RA patients between 2002 and 2011. What was most striking about our observation was that the rise in utilization appeared to be driven by an increase in TSA, whereas the utilization of HA decreased over time. This change in practice likely reflects several factors, including the multitude of studies that have demonstrated improved outcomes with anatomic TSA as compared with HA in RA patients.^10-14

Perhaps the most interesting aspect of our data was the recent exponential rise in the utilization of the reverse TSA. Despite improved outcomes following TSA as compared with HA in RA patients, these outcomes all appear to be highly dependent upon the integrity of the rotator cuff.¹⁰ In fact, there is evidence that failure of the rotator cuff could be as high as 75% within 10 years of TSA in patients with RA,¹⁵ which ultimately could jeopardize the long-term durability of the TSA implant in this patient population.¹¹ For this reason, interest in the reverse TSA for the RA patient population has increased since its introduction in the US in 2004;¹⁶ in fact, in RA patients with end-stage inflammatory arthropathy and a damaged rotator cuff, the reverse TSA has demonstrated excellent results.^17-20 Based upon this evidence, it is not surprising that we found an exponential rise in the use of the reverse TSA since 2010, which corresponds to the introduction of an ICD-9 code for this implant.²¹ Prior to 2010, it is likely that many implanted reverse TSAs were coded as TSA, and for this reason, we believe that the observed rise in the utilization of TSA in RA patients prior to 2010 may have been partly fueled by an increase in the use of the reverse TSA. To further support this theory, there was a dramatic decrease in the use of anatomic TSA following 2010, and we believe this was related to increased awareness of the newly introduced reverse TSA code among surgeons.

Another consideration when examining the utilization of shoulder arthroplasty in RA patients is its versatility in managing different disease states, including rotator cuff disease. As has been documented in the literature, outcomes of rotator cuff repair in RA patients are discouraging.²² For this reason, it is reasonable for surgeons and patients with RA to consider alternatives to rotator cuff repair when nonoperative management has failed to provide adequate improvement in symptoms. One alternative may be shoulder arthroplasty, namely the reverse TSA. In this study, we observed a significant increase in the rate of diagnosis of rotator cuff disease among RA patients undergoing shoulder arthroplasty from 2002 to 2011 (9.7% in 2002 to 15.2% in 2011, P < .001), and it is our belief that the simultaneous increase in the diagnosis of rotator cuff disease and use of TSA is not coincidental. More specifically, there is likely an emerging trend among surgeons toward using the reverse TSA to manage rotator cuff tears in the RA population, rather than undertaking a rotator cuff repair that carries a high rate of failure. Going forward, there is a need to not only identify this trend more clearly but to also compare the outcomes between reverse TSA and rotator cuff repair in the management of rotator cuff tears in RA patients.

Continue to: In this study, we observed...

In this study, we observed that RA patients undergoing shoulder arthroplasty were significantly younger than non-RA patients undergoing shoulder arthroplasty. At first, this observation seems to counter recent literature suggesting that the age of patients with inflammatory arthropathy undergoing TJA is increasing over time;¹ however, looking more closely at the data, it becomes clearer that the mean age we report is actually a relative increase as compared with past clinical studies pertaining to RA patients undergoing shoulder arthroplasty (mean ages of 47 years,²³ 55 years,²⁴ 60 years,¹⁰ and 62 years²⁵). On the other hand, the continued existence of an age gap between RA and non-RA patients undergoing shoulder arthroplasty may be the result of several possible phenomena. First, this may reflect issues with patient access to and coverage of expensive biologic antirheumatic medication that would otherwise mitigate disease progression. For instance, the out-of-pocket expense for biologic medication through Medicaid and Medicare is substantial,²⁶ which has direct implications on over two-thirds of our RA cohort. Second, it may be skewed by the proportion of RA patients who have previously been or continue to be poorly managed, enabling disease progression to end-stage arthropathy at a younger age. Ultimately, further investigation is needed to determine the reasons for this continued age disparity.

In comparing RA and non-RA patients undergoing shoulder arthroplasty, we did not find a significant difference in the overall nor the individual rates of early adverse events. This finding appears to be unique, as similar studies pertaining to total knee arthroplasty (TKA) demonstrated a significantly higher incidence of postoperative pneumonia and bleeding requiring transfusion among RA patients as compared with non-RA patients.²⁷ In patients with RA being treated with biologic medication and undergoing shoulder arthroplasty, the frequent concern in the postoperative period is the integrity of the wound and the potential for infection.²⁸ In this study, we did not find a significant difference in the rate of early infection, and although the difference in the rate of early wound dehiscence approached significance, it did not meet the threshold of 0.05 (P = .09). This finding is in keeping with the aforementioned NIS study pertaining to TKA, and we believe that it likely reflects the short duration of follow-up for patients in both studies. Given the nature of the database we utilized, we were only privy to complications that arose during the inpatient hospital stay, and it is likely that the clear majority of patients who develop a postoperative infection or wound dehiscence do so in the postoperative setting following discharge. A second concern regarding postoperative wound complications is the management of biologic medication in the perioperative period, which we cannot determine using this database. Despite all these limitations specific to this database, a past systematic review of reverse TSA in RA patients found a low rate of deep infection after reverse TSA in RA patients (3.3%),¹⁷ which was not higher than that after shoulder arthroplasty performed in non-RA patients.

A final demonstration from this study is that the hospital length of stay was significantly longer for RA patients than non-RA patients undergoing shoulder arthroplasty; however, given that the difference was only 0.1 days, and there was no significant difference in hospitalization cost, we are inclined to believe that statistical significance may not translate into clinical significance in this scenario. Ultimately, we do believe that length of stay is an important consideration in the current healthcare system, and given our finding that shoulder arthroplasty in the RA patient is safe in the early postoperative period, that a prolonged postoperative hospitalization is not warranted on the sole basis of a patient’s history of RA.

As with all studies using data from a search of an administrative database, such as the NIS database, this study has limitations. First, this type of research is limited by the reliability of both diagnosis and procedural coding. Although the NIS database has demonstrated high reliability,³ it is still possible that events may have been miscoded. Second, the tracking period for adverse events is limited to the inpatient hospital stay, which may be too short to detect certain postoperative complications. As such, the rates we report are likely underestimates of the true incidence of these complications, but this is true for both the RA and non-RA populations. Third, the comparisons we draw between RA and non-RA patients are limited to the scope of the NIS database and the available data; as such, we could not draw comparisons between preoperative disease stage, intraoperative findings, and postoperative course following hospital discharge. Lastly, our data are limited to a distinct period between 2002 and 2011 and may not reflect current practice. Ultimately, our findings may underestimate current trends in shoulder arthroplasty utilization among RA patients, particularly for the reverse TSA.

CONCLUSION

In this study, we found that the utilization of shoulder arthroplasty in patients with RA increased significantly from 2002 to 2011, largely related to a rise in the utilization of TSA. Similarly, we observed a rise in the proportion of RA patients undergoing shoulder arthroplasty with a corresponding diagnosis of rotator cuff disease, and we believe the increased utilization of shoulder arthroplasty among RA patients resulted from management of both end-stage inflammatory arthropathy and rotator cuff disease. Although we did not find a significant difference between RA and non-RA patients in the rates of early adverse events and overall hospitalization costs following shoulder arthroplasty, length of stay was significantly longer among RA patients; however, the absolute difference does not appear to be clinically significant.

ABSTRACT

Postoperative pain management is an important component of total shoulder arthroplasty (TSA). Continuous cryotherapy (CC) has been proposed as a means of improving postoperative pain control. However, CC represents an increased cost not typically covered by insurance. The purpose of this study is to compare CC to plain ice (ICE) following TSA. The hypothesis was that CC would lead to lower pain scores and decreased narcotic usage during the first 2 weeks postoperatively.

A randomized controlled trial was performed to compare CC to ICE. Forty patients were randomized to receive either CC or ICE following TSA. The rehabilitation and pain control protocols were otherwise standardized. Visual analog scales (VAS) for pain, satisfaction with cold therapy, and quality of sleep were recorded preoperatively and postoperatively at 24 hours, 3 days, 7 days, and 14 days following surgery. Narcotic usage in morphine equivalents was also recorded. 

No significant differences in preoperative pain (5.9 vs 6.8; P = .121), or postoperative pain at 24 hours (4.2 vs 4.3; P = .989), 3 days (4.8 vs 4.7; P = .944), 7 days (2.9 vs 3.3; P = .593) or 14 days (2.5 vs 2.7; P = .742) were observed between the CC and ICE groups. Similarly, no differences in quality of sleep, satisfaction with the cold therapy, or narcotic usage at any time interval were observed between the 2 groups.

No differences in pain control, quality of sleep, patient satisfaction, or narcotic usage were detected between CC and ICE following TSA. CC may offer convenience as an advantage, but the increased cost associated with this type of treatment may not be justified.

The number of total shoulder arthroplasties (TSAs) performed annually is increasing dramatically.¹ At the same time, there has been a push toward decreased length of hospital stay and earlier mobilization following joint replacement surgery. Central to these goals is adequate pain control. Multimodal pain pathways exist, and one of the safest and cheapest methods of pain control is cold therapy, which can be accomplished with continuous cryotherapy (CC) or plain ice (ICE).

Continue to: The mechanism of cryotherapy...

The knee literature contains multiple studies that have examined the benefits of cryotherapy after both arthroscopic and arthroplasty procedures. The clinical benefits on pain have been equivocal with some studies showing improvements using cryotherapy^3,4 and others showing no difference in the treatment group.^5,6

Few studies have examined cryotherapy for the shoulder. Speer and colleagues⁷ demonstrated that postoperative use of CC was effective in reducing recovery time after shoulder surgery. However; they did not provide an ICE comparative group and did not focus specifically on TSA. In another study, Kraeutler and colleagues⁸ examined only arthroscopic shoulder surgery cases in a randomized prospective trial and found no significant different between CC and ICE. They concluded that there did not appear to be a significant benefit in using CC over ICE for arthroscopic shoulder procedures.

The purpose of this study is to prospectively evaluate CC and ICE following TSA. The hypothesis was that CC leads to improved pain control, less narcotic consumption, and improved quality of sleep compared to ICE in the immediate postoperative period following TSA.

MATERIALS AND METHODS

This was a prospective randomized control study of patients undergoing TSA receiving either CC or ICE postoperatively. Institutional Review Board approval was obtained before commencement of the study. Inclusion criteria included patients aged 30 to 90 years old undergoing a primary or revision shoulder arthroplasty procedure between June 2015 and January 2016. Exclusion criteria included hemiarthroplasty procedures.

Continue to: Three patients refused...

Table 1. Summary of Surgical Cases

Abbreviations: CC, continuous cryotherapy; ICE, plain ice; RSA, reverse shoulder arthroplasty; TSA, total shoulder arthroplasty.

All surgeries were performed by Dr. Denard. All patients received a single-shot interscalene nerve block prior to the procedure. A deltopectoral approach was utilized, and the subscapularis was managed with the peel technique.⁹ All patients were admitted to the hospital following surgery. Standard postoperative pain control consisted of as-needed intravenous morphine (1-2 mg every 2 hours, as needed) or an oral narcotic (hydrocodone/acetaminophen 5/325mg, 1-2 every 4 hours, as needed) which was also provided at discharge. However, total narcotic usage was recorded in morphine equivalents to account for substitutions. No non-steroidal anti-inflammatory drugs were allowed until 3 months postoperatively. 

The CC group received treatment from a commercially available cryotherapy unit (Polar Care; Breg). All patients received instructions by a medical professional on how to use the unit. The unit was applied immediately postoperatively and set at a temperature of 45°F to 55°F. Patients were instructed to use the unit continuously during postoperative days 0 to 3. This cryotherapy was administered by a nurse while in the hospital but was left to the responsibility of the patient upon discharge. Patients were instructed to use the unit as needed for pain control during the day and continuously while asleep from days 4 to14. 

The ICE group used standard ice packs postoperatively. The patients were instructed to apply an ice pack for 20 min every 2 hours while awake during days 0 to 3. This therapy was administered by a nurse while in the hospital but left to the responsibility of the patient upon discharge. Patients were instructed to use ice packs as needed for pain control during the day at a maximum of 20 minutes per hour on postoperative days 4 to 14. Compliance by both groups was monitored using a patient survey after hospital discharge. The number of hours that patients used either the CC or ICE per 24-hour period was recorded at 24 hours, 3 days, 7 days, and 14 days. The nursing staff recorded the number of hours of use of either cold modality for each patient prior to hospital discharge. The average length of stay as an inpatient was 1.2 days for the CC group and 1.3 days for the ICE group. 

Visual analog scales (VAS) for pain, satisfaction with the cold therapy, and quality of sleep were recorded preoperatively and postoperatively at 24 hours, 3 days, 7 days, and 14 days following surgery. 

Continue to: The Wilcoxon rank-sum test...

STATISTICAL METHOD

The Wilcoxon rank-sum test was used to assess whether scores changed significantly from the preoperative period to the different postoperative time intervals, as well as to assess the values for pain, quality of sleep, and patient satisfaction. P-values <.05 were considered significant.

RESULTS

No differences were observed in the baseline characteristics between the 2 groups. Both groups showed improvements in pain, quality of sleep, and satisfaction with the cold therapy from the preoperative period to the final follow-up.

The VAS pain scores were not different between the CC and ICE groups preoperatively (5.9 vs 6.8; P = .121) or postoperatively at 24 hours (4.2 vs 4.3; P = .989), 3 days (4.8 vs 4.7; P = .944), 7 days (2.9 vs 3.3; P = .593), or 14 days (2.5 vs 2.7; P = .742).  Both cohorts demonstrated improved overall pain throughout the study period. These findings are summarized in Table 2. 

Table 2. Summary of VAS Pain Scores With Cold Therapy

Abbreviations: CC, continuous cryotherapy; CI, confidence interval; ICE, plain ice; VAS, visual analog scales.

The number of morphine equivalents of pain medication was not different between the CC and ICE groups postoperatively at 24 hours (43 vs 38 mg; P = .579), 3 days (149 vs 116 mg; P = .201), 7 days (308 vs 228 mg; P = .181), or 14 days (431 vs 348 mg; P = .213). Both groups showed increased narcotic consumption from 24 hours postoperatively until the 2-week follow-up. Narcotic consumption is summarized in Table 3.

Table 3. Summary of Narcotic Consumption in Morphine Equivalents

Abbreviations: CC, continuous cryotherapy; CI, confidence interval; ICE, plain ice.

VAS for quality of sleep improved in both groups from 24 hours postoperatively until the final follow-up. However, no significant differences in sleep quality were observed between the CC and ICE groups postoperatively at 24 hours (5.1 vs 4.3; P = .382), 3 days (5.1 vs 5.3; P = .601), 7 days (6.0 vs 6.7; P = .319), or 14 days (6.5 vs 7.1; P = .348). The VAS scores for sleep quality are reported in Table 4.

Table 4. Summary of VAS Sleep Quality With Cold Therapy^a

^a0-10 rating with 10 being the highest possible score.

Abbreviations: CC, continuous cryotherapy; CI, confidence interval; ICE, plain ice; VAS, visual analog scales.

Continue to: Finally, VAS patient satisfaction...

While compliance within each group utilizing the randomly assigned cold modality was similar, the usage by the CC group was consistently higher at all time points recorded. No complications or reoperations were observed in either group.

DISCUSSION

The optimal method for managing postoperative pain from an arthroplasty procedure is controversial. This prospective randomized study attempted to confirm the hypothesis that CC infers better pain control, improves quality of sleep, and decreases narcotic usage compared to ICE in the first 2 weeks after a TSA procedure. The results of this study refuted our hypothesis, demonstrating no significant difference in pain control, satisfaction, narcotic usage, or sleep quality between the CC and ICE cohorts at all time points studied. 

Studies on knees and lower extremities demonstrate equivocal results for the role CC plays in providing improved postoperative pain control. Thienpont¹⁰ evaluated CC in a randomized control trial comparing plain ice packs postoperatively in patients who underwent TKA. The author found no significant difference in VAS for pain or narcotic consumption in morphine equivalents. Thienpont¹⁰ recommended that CC not be used for outpatient knee arthroplasty as it is an additional cost that does not improve pain significantly. Healy and colleagues⁵ reported similar results that CC did not demonstrate a difference in narcotic requirement or pain control compared to plain ice packs, as well as no difference in local postoperative swelling or wound drainage. However, a recently published randomized trial by Su and colleagues¹¹ comparing a cryopneumatic device and ICE with static compression in patients who underwent TKA demonstrated significantly lower narcotic consumption and increased ambulation distances in the treatment group. The treatment group consumed approximately 170 mg morphine equivalents less than the control group between discharge and the 2-week postoperative visit. In addition, a significant difference was observed in the satisfaction scores in the treatment group.¹¹ Similarly, a meta-analysis by Raynor and colleagues¹² on randomized clinical trials comparing cryotherapy to a placebo group after anterior cruciate ligament reconstruction showed that cryotherapy is associated with significantly lower postoperative pain (P = .02), but demonstrated no difference in postoperative drainage (P = .23) or range of motion (P = .25).

Although multiple studies have been published regarding the efficacy of cryotherapy after knee surgery, very few studies have compared CC to conventional ICE after shoulder surgery. A prospective randomized trial was performed by Singh and colleagues¹³ to compare CC vs no ICE in open and arthroscopic shoulder surgery patients. Both the open and arthroscopic groups receiving CC demonstrated significant reductions in pain frequency and more restful sleep at the 7-day, 14-day, and 21-day intervals compared to the control group. However, they did not compare the commercial unit to ICE. In contrast, a study by Kraeutler and colleagues⁸ randomized 46 patients to receive either CC or ICE in the setting of arthroscopic shoulder surgery. Although no significant difference was observed in morphine equivalent dosage between the 2 groups, the CC group used more pain medication on every postoperative day during the first week after surgery. They found no difference between the 2 groups with regards to narcotic consumption or pain scores. The results of this study mirror those by Kraeutler and colleagues,⁸ demonstrating no difference in pain scores, sleep quality, or narcotic consumption.

Continue to: With rising costs in the US...

The major strengths of this study are the randomized design and multiple data points during the early postoperative period. However, there are several limitations. First, we did not objectively measure compliance of either therapy and relied only on a patient survey. Usage of the commercial CC unit in hours decreased over half between days 3 and 14. This occurred despite training on the application and specific instructions. We believe this reflects “real-world” usage, but it is possible that compliance affected our results. Second, all patients in this study had a single-shot interscalene block. While this is standard at our institution, it is possible that either CC or ICE would have a more significant effect in the absence of an interscalene block. Finally, we did not evaluate final outcomes in this study and therefore cannot determine if the final outcome was different between the 2 groups. Our goal was simply to evaluate the first 2 weeks following surgery, as this is the most painful period following TSA. 

CONCLUSION

There was no difference between CC and ICE in terms of pain control, quality of sleep, patient satisfaction, or narcotic consumption following TSA. CC may offer convenience advantages, but the increased cost associated with this type of unit may not be justified. 

ABSTRACT

Postoperative pain management is an important component of total shoulder arthroplasty (TSA). Continuous cryotherapy (CC) has been proposed as a means of improving postoperative pain control. However, CC represents an increased cost not typically covered by insurance. The purpose of this study is to compare CC to plain ice (ICE) following TSA. The hypothesis was that CC would lead to lower pain scores and decreased narcotic usage during the first 2 weeks postoperatively.

A randomized controlled trial was performed to compare CC to ICE. Forty patients were randomized to receive either CC or ICE following TSA. The rehabilitation and pain control protocols were otherwise standardized. Visual analog scales (VAS) for pain, satisfaction with cold therapy, and quality of sleep were recorded preoperatively and postoperatively at 24 hours, 3 days, 7 days, and 14 days following surgery. Narcotic usage in morphine equivalents was also recorded. 

No significant differences in preoperative pain (5.9 vs 6.8; P = .121), or postoperative pain at 24 hours (4.2 vs 4.3; P = .989), 3 days (4.8 vs 4.7; P = .944), 7 days (2.9 vs 3.3; P = .593) or 14 days (2.5 vs 2.7; P = .742) were observed between the CC and ICE groups. Similarly, no differences in quality of sleep, satisfaction with the cold therapy, or narcotic usage at any time interval were observed between the 2 groups.

No differences in pain control, quality of sleep, patient satisfaction, or narcotic usage were detected between CC and ICE following TSA. CC may offer convenience as an advantage, but the increased cost associated with this type of treatment may not be justified.

The number of total shoulder arthroplasties (TSAs) performed annually is increasing dramatically.¹ At the same time, there has been a push toward decreased length of hospital stay and earlier mobilization following joint replacement surgery. Central to these goals is adequate pain control. Multimodal pain pathways exist, and one of the safest and cheapest methods of pain control is cold therapy, which can be accomplished with continuous cryotherapy (CC) or plain ice (ICE).

Continue to: The mechanism of cryotherapy...

The knee literature contains multiple studies that have examined the benefits of cryotherapy after both arthroscopic and arthroplasty procedures. The clinical benefits on pain have been equivocal with some studies showing improvements using cryotherapy^3,4 and others showing no difference in the treatment group.^5,6

Few studies have examined cryotherapy for the shoulder. Speer and colleagues⁷ demonstrated that postoperative use of CC was effective in reducing recovery time after shoulder surgery. However; they did not provide an ICE comparative group and did not focus specifically on TSA. In another study, Kraeutler and colleagues⁸ examined only arthroscopic shoulder surgery cases in a randomized prospective trial and found no significant different between CC and ICE. They concluded that there did not appear to be a significant benefit in using CC over ICE for arthroscopic shoulder procedures.

The purpose of this study is to prospectively evaluate CC and ICE following TSA. The hypothesis was that CC leads to improved pain control, less narcotic consumption, and improved quality of sleep compared to ICE in the immediate postoperative period following TSA.

MATERIALS AND METHODS

This was a prospective randomized control study of patients undergoing TSA receiving either CC or ICE postoperatively. Institutional Review Board approval was obtained before commencement of the study. Inclusion criteria included patients aged 30 to 90 years old undergoing a primary or revision shoulder arthroplasty procedure between June 2015 and January 2016. Exclusion criteria included hemiarthroplasty procedures.

Continue to: Three patients refused...

Table 1. Summary of Surgical Cases

Abbreviations: CC, continuous cryotherapy; ICE, plain ice; RSA, reverse shoulder arthroplasty; TSA, total shoulder arthroplasty.

All surgeries were performed by Dr. Denard. All patients received a single-shot interscalene nerve block prior to the procedure. A deltopectoral approach was utilized, and the subscapularis was managed with the peel technique.⁹ All patients were admitted to the hospital following surgery. Standard postoperative pain control consisted of as-needed intravenous morphine (1-2 mg every 2 hours, as needed) or an oral narcotic (hydrocodone/acetaminophen 5/325mg, 1-2 every 4 hours, as needed) which was also provided at discharge. However, total narcotic usage was recorded in morphine equivalents to account for substitutions. No non-steroidal anti-inflammatory drugs were allowed until 3 months postoperatively. 

The CC group received treatment from a commercially available cryotherapy unit (Polar Care; Breg). All patients received instructions by a medical professional on how to use the unit. The unit was applied immediately postoperatively and set at a temperature of 45°F to 55°F. Patients were instructed to use the unit continuously during postoperative days 0 to 3. This cryotherapy was administered by a nurse while in the hospital but was left to the responsibility of the patient upon discharge. Patients were instructed to use the unit as needed for pain control during the day and continuously while asleep from days 4 to14. 

The ICE group used standard ice packs postoperatively. The patients were instructed to apply an ice pack for 20 min every 2 hours while awake during days 0 to 3. This therapy was administered by a nurse while in the hospital but left to the responsibility of the patient upon discharge. Patients were instructed to use ice packs as needed for pain control during the day at a maximum of 20 minutes per hour on postoperative days 4 to 14. Compliance by both groups was monitored using a patient survey after hospital discharge. The number of hours that patients used either the CC or ICE per 24-hour period was recorded at 24 hours, 3 days, 7 days, and 14 days. The nursing staff recorded the number of hours of use of either cold modality for each patient prior to hospital discharge. The average length of stay as an inpatient was 1.2 days for the CC group and 1.3 days for the ICE group. 

Visual analog scales (VAS) for pain, satisfaction with the cold therapy, and quality of sleep were recorded preoperatively and postoperatively at 24 hours, 3 days, 7 days, and 14 days following surgery. 

Continue to: The Wilcoxon rank-sum test...

STATISTICAL METHOD

The Wilcoxon rank-sum test was used to assess whether scores changed significantly from the preoperative period to the different postoperative time intervals, as well as to assess the values for pain, quality of sleep, and patient satisfaction. P-values <.05 were considered significant.

RESULTS

No differences were observed in the baseline characteristics between the 2 groups. Both groups showed improvements in pain, quality of sleep, and satisfaction with the cold therapy from the preoperative period to the final follow-up.

The VAS pain scores were not different between the CC and ICE groups preoperatively (5.9 vs 6.8; P = .121) or postoperatively at 24 hours (4.2 vs 4.3; P = .989), 3 days (4.8 vs 4.7; P = .944), 7 days (2.9 vs 3.3; P = .593), or 14 days (2.5 vs 2.7; P = .742).  Both cohorts demonstrated improved overall pain throughout the study period. These findings are summarized in Table 2. 

Table 2. Summary of VAS Pain Scores With Cold Therapy

Abbreviations: CC, continuous cryotherapy; CI, confidence interval; ICE, plain ice; VAS, visual analog scales.

The number of morphine equivalents of pain medication was not different between the CC and ICE groups postoperatively at 24 hours (43 vs 38 mg; P = .579), 3 days (149 vs 116 mg; P = .201), 7 days (308 vs 228 mg; P = .181), or 14 days (431 vs 348 mg; P = .213). Both groups showed increased narcotic consumption from 24 hours postoperatively until the 2-week follow-up. Narcotic consumption is summarized in Table 3.

Table 3. Summary of Narcotic Consumption in Morphine Equivalents

Abbreviations: CC, continuous cryotherapy; CI, confidence interval; ICE, plain ice.

VAS for quality of sleep improved in both groups from 24 hours postoperatively until the final follow-up. However, no significant differences in sleep quality were observed between the CC and ICE groups postoperatively at 24 hours (5.1 vs 4.3; P = .382), 3 days (5.1 vs 5.3; P = .601), 7 days (6.0 vs 6.7; P = .319), or 14 days (6.5 vs 7.1; P = .348). The VAS scores for sleep quality are reported in Table 4.

Table 4. Summary of VAS Sleep Quality With Cold Therapy^a

^a0-10 rating with 10 being the highest possible score.

Abbreviations: CC, continuous cryotherapy; CI, confidence interval; ICE, plain ice; VAS, visual analog scales.

Continue to: Finally, VAS patient satisfaction...

While compliance within each group utilizing the randomly assigned cold modality was similar, the usage by the CC group was consistently higher at all time points recorded. No complications or reoperations were observed in either group.

DISCUSSION

The optimal method for managing postoperative pain from an arthroplasty procedure is controversial. This prospective randomized study attempted to confirm the hypothesis that CC infers better pain control, improves quality of sleep, and decreases narcotic usage compared to ICE in the first 2 weeks after a TSA procedure. The results of this study refuted our hypothesis, demonstrating no significant difference in pain control, satisfaction, narcotic usage, or sleep quality between the CC and ICE cohorts at all time points studied. 

Studies on knees and lower extremities demonstrate equivocal results for the role CC plays in providing improved postoperative pain control. Thienpont¹⁰ evaluated CC in a randomized control trial comparing plain ice packs postoperatively in patients who underwent TKA. The author found no significant difference in VAS for pain or narcotic consumption in morphine equivalents. Thienpont¹⁰ recommended that CC not be used for outpatient knee arthroplasty as it is an additional cost that does not improve pain significantly. Healy and colleagues⁵ reported similar results that CC did not demonstrate a difference in narcotic requirement or pain control compared to plain ice packs, as well as no difference in local postoperative swelling or wound drainage. However, a recently published randomized trial by Su and colleagues¹¹ comparing a cryopneumatic device and ICE with static compression in patients who underwent TKA demonstrated significantly lower narcotic consumption and increased ambulation distances in the treatment group. The treatment group consumed approximately 170 mg morphine equivalents less than the control group between discharge and the 2-week postoperative visit. In addition, a significant difference was observed in the satisfaction scores in the treatment group.¹¹ Similarly, a meta-analysis by Raynor and colleagues¹² on randomized clinical trials comparing cryotherapy to a placebo group after anterior cruciate ligament reconstruction showed that cryotherapy is associated with significantly lower postoperative pain (P = .02), but demonstrated no difference in postoperative drainage (P = .23) or range of motion (P = .25).

Although multiple studies have been published regarding the efficacy of cryotherapy after knee surgery, very few studies have compared CC to conventional ICE after shoulder surgery. A prospective randomized trial was performed by Singh and colleagues¹³ to compare CC vs no ICE in open and arthroscopic shoulder surgery patients. Both the open and arthroscopic groups receiving CC demonstrated significant reductions in pain frequency and more restful sleep at the 7-day, 14-day, and 21-day intervals compared to the control group. However, they did not compare the commercial unit to ICE. In contrast, a study by Kraeutler and colleagues⁸ randomized 46 patients to receive either CC or ICE in the setting of arthroscopic shoulder surgery. Although no significant difference was observed in morphine equivalent dosage between the 2 groups, the CC group used more pain medication on every postoperative day during the first week after surgery. They found no difference between the 2 groups with regards to narcotic consumption or pain scores. The results of this study mirror those by Kraeutler and colleagues,⁸ demonstrating no difference in pain scores, sleep quality, or narcotic consumption.

Continue to: With rising costs in the US...

The major strengths of this study are the randomized design and multiple data points during the early postoperative period. However, there are several limitations. First, we did not objectively measure compliance of either therapy and relied only on a patient survey. Usage of the commercial CC unit in hours decreased over half between days 3 and 14. This occurred despite training on the application and specific instructions. We believe this reflects “real-world” usage, but it is possible that compliance affected our results. Second, all patients in this study had a single-shot interscalene block. While this is standard at our institution, it is possible that either CC or ICE would have a more significant effect in the absence of an interscalene block. Finally, we did not evaluate final outcomes in this study and therefore cannot determine if the final outcome was different between the 2 groups. Our goal was simply to evaluate the first 2 weeks following surgery, as this is the most painful period following TSA. 

CONCLUSION

There was no difference between CC and ICE in terms of pain control, quality of sleep, patient satisfaction, or narcotic consumption following TSA. CC may offer convenience advantages, but the increased cost associated with this type of unit may not be justified. 

ABSTRACT

Postoperative pain management is an important component of total shoulder arthroplasty (TSA). Continuous cryotherapy (CC) has been proposed as a means of improving postoperative pain control. However, CC represents an increased cost not typically covered by insurance. The purpose of this study is to compare CC to plain ice (ICE) following TSA. The hypothesis was that CC would lead to lower pain scores and decreased narcotic usage during the first 2 weeks postoperatively.

A randomized controlled trial was performed to compare CC to ICE. Forty patients were randomized to receive either CC or ICE following TSA. The rehabilitation and pain control protocols were otherwise standardized. Visual analog scales (VAS) for pain, satisfaction with cold therapy, and quality of sleep were recorded preoperatively and postoperatively at 24 hours, 3 days, 7 days, and 14 days following surgery. Narcotic usage in morphine equivalents was also recorded. 

No significant differences in preoperative pain (5.9 vs 6.8; P = .121), or postoperative pain at 24 hours (4.2 vs 4.3; P = .989), 3 days (4.8 vs 4.7; P = .944), 7 days (2.9 vs 3.3; P = .593) or 14 days (2.5 vs 2.7; P = .742) were observed between the CC and ICE groups. Similarly, no differences in quality of sleep, satisfaction with the cold therapy, or narcotic usage at any time interval were observed between the 2 groups.

No differences in pain control, quality of sleep, patient satisfaction, or narcotic usage were detected between CC and ICE following TSA. CC may offer convenience as an advantage, but the increased cost associated with this type of treatment may not be justified.

The number of total shoulder arthroplasties (TSAs) performed annually is increasing dramatically.¹ At the same time, there has been a push toward decreased length of hospital stay and earlier mobilization following joint replacement surgery. Central to these goals is adequate pain control. Multimodal pain pathways exist, and one of the safest and cheapest methods of pain control is cold therapy, which can be accomplished with continuous cryotherapy (CC) or plain ice (ICE).

Continue to: The mechanism of cryotherapy...

The knee literature contains multiple studies that have examined the benefits of cryotherapy after both arthroscopic and arthroplasty procedures. The clinical benefits on pain have been equivocal with some studies showing improvements using cryotherapy^3,4 and others showing no difference in the treatment group.^5,6

Few studies have examined cryotherapy for the shoulder. Speer and colleagues⁷ demonstrated that postoperative use of CC was effective in reducing recovery time after shoulder surgery. However; they did not provide an ICE comparative group and did not focus specifically on TSA. In another study, Kraeutler and colleagues⁸ examined only arthroscopic shoulder surgery cases in a randomized prospective trial and found no significant different between CC and ICE. They concluded that there did not appear to be a significant benefit in using CC over ICE for arthroscopic shoulder procedures.

The purpose of this study is to prospectively evaluate CC and ICE following TSA. The hypothesis was that CC leads to improved pain control, less narcotic consumption, and improved quality of sleep compared to ICE in the immediate postoperative period following TSA.

MATERIALS AND METHODS

This was a prospective randomized control study of patients undergoing TSA receiving either CC or ICE postoperatively. Institutional Review Board approval was obtained before commencement of the study. Inclusion criteria included patients aged 30 to 90 years old undergoing a primary or revision shoulder arthroplasty procedure between June 2015 and January 2016. Exclusion criteria included hemiarthroplasty procedures.

Continue to: Three patients refused...

Table 1. Summary of Surgical Cases

Abbreviations: CC, continuous cryotherapy; ICE, plain ice; RSA, reverse shoulder arthroplasty; TSA, total shoulder arthroplasty.

All surgeries were performed by Dr. Denard. All patients received a single-shot interscalene nerve block prior to the procedure. A deltopectoral approach was utilized, and the subscapularis was managed with the peel technique.⁹ All patients were admitted to the hospital following surgery. Standard postoperative pain control consisted of as-needed intravenous morphine (1-2 mg every 2 hours, as needed) or an oral narcotic (hydrocodone/acetaminophen 5/325mg, 1-2 every 4 hours, as needed) which was also provided at discharge. However, total narcotic usage was recorded in morphine equivalents to account for substitutions. No non-steroidal anti-inflammatory drugs were allowed until 3 months postoperatively. 

The CC group received treatment from a commercially available cryotherapy unit (Polar Care; Breg). All patients received instructions by a medical professional on how to use the unit. The unit was applied immediately postoperatively and set at a temperature of 45°F to 55°F. Patients were instructed to use the unit continuously during postoperative days 0 to 3. This cryotherapy was administered by a nurse while in the hospital but was left to the responsibility of the patient upon discharge. Patients were instructed to use the unit as needed for pain control during the day and continuously while asleep from days 4 to14. 

The ICE group used standard ice packs postoperatively. The patients were instructed to apply an ice pack for 20 min every 2 hours while awake during days 0 to 3. This therapy was administered by a nurse while in the hospital but left to the responsibility of the patient upon discharge. Patients were instructed to use ice packs as needed for pain control during the day at a maximum of 20 minutes per hour on postoperative days 4 to 14. Compliance by both groups was monitored using a patient survey after hospital discharge. The number of hours that patients used either the CC or ICE per 24-hour period was recorded at 24 hours, 3 days, 7 days, and 14 days. The nursing staff recorded the number of hours of use of either cold modality for each patient prior to hospital discharge. The average length of stay as an inpatient was 1.2 days for the CC group and 1.3 days for the ICE group. 

Visual analog scales (VAS) for pain, satisfaction with the cold therapy, and quality of sleep were recorded preoperatively and postoperatively at 24 hours, 3 days, 7 days, and 14 days following surgery. 

Continue to: The Wilcoxon rank-sum test...

STATISTICAL METHOD

The Wilcoxon rank-sum test was used to assess whether scores changed significantly from the preoperative period to the different postoperative time intervals, as well as to assess the values for pain, quality of sleep, and patient satisfaction. P-values <.05 were considered significant.

RESULTS

No differences were observed in the baseline characteristics between the 2 groups. Both groups showed improvements in pain, quality of sleep, and satisfaction with the cold therapy from the preoperative period to the final follow-up.

The VAS pain scores were not different between the CC and ICE groups preoperatively (5.9 vs 6.8; P = .121) or postoperatively at 24 hours (4.2 vs 4.3; P = .989), 3 days (4.8 vs 4.7; P = .944), 7 days (2.9 vs 3.3; P = .593), or 14 days (2.5 vs 2.7; P = .742).  Both cohorts demonstrated improved overall pain throughout the study period. These findings are summarized in Table 2. 

Table 2. Summary of VAS Pain Scores With Cold Therapy

Abbreviations: CC, continuous cryotherapy; CI, confidence interval; ICE, plain ice; VAS, visual analog scales.

The number of morphine equivalents of pain medication was not different between the CC and ICE groups postoperatively at 24 hours (43 vs 38 mg; P = .579), 3 days (149 vs 116 mg; P = .201), 7 days (308 vs 228 mg; P = .181), or 14 days (431 vs 348 mg; P = .213). Both groups showed increased narcotic consumption from 24 hours postoperatively until the 2-week follow-up. Narcotic consumption is summarized in Table 3.

Table 3. Summary of Narcotic Consumption in Morphine Equivalents

Abbreviations: CC, continuous cryotherapy; CI, confidence interval; ICE, plain ice.

VAS for quality of sleep improved in both groups from 24 hours postoperatively until the final follow-up. However, no significant differences in sleep quality were observed between the CC and ICE groups postoperatively at 24 hours (5.1 vs 4.3; P = .382), 3 days (5.1 vs 5.3; P = .601), 7 days (6.0 vs 6.7; P = .319), or 14 days (6.5 vs 7.1; P = .348). The VAS scores for sleep quality are reported in Table 4.

Table 4. Summary of VAS Sleep Quality With Cold Therapy^a

^a0-10 rating with 10 being the highest possible score.

Abbreviations: CC, continuous cryotherapy; CI, confidence interval; ICE, plain ice; VAS, visual analog scales.

Continue to: Finally, VAS patient satisfaction...

While compliance within each group utilizing the randomly assigned cold modality was similar, the usage by the CC group was consistently higher at all time points recorded. No complications or reoperations were observed in either group.

DISCUSSION

The optimal method for managing postoperative pain from an arthroplasty procedure is controversial. This prospective randomized study attempted to confirm the hypothesis that CC infers better pain control, improves quality of sleep, and decreases narcotic usage compared to ICE in the first 2 weeks after a TSA procedure. The results of this study refuted our hypothesis, demonstrating no significant difference in pain control, satisfaction, narcotic usage, or sleep quality between the CC and ICE cohorts at all time points studied. 

Studies on knees and lower extremities demonstrate equivocal results for the role CC plays in providing improved postoperative pain control. Thienpont¹⁰ evaluated CC in a randomized control trial comparing plain ice packs postoperatively in patients who underwent TKA. The author found no significant difference in VAS for pain or narcotic consumption in morphine equivalents. Thienpont¹⁰ recommended that CC not be used for outpatient knee arthroplasty as it is an additional cost that does not improve pain significantly. Healy and colleagues⁵ reported similar results that CC did not demonstrate a difference in narcotic requirement or pain control compared to plain ice packs, as well as no difference in local postoperative swelling or wound drainage. However, a recently published randomized trial by Su and colleagues¹¹ comparing a cryopneumatic device and ICE with static compression in patients who underwent TKA demonstrated significantly lower narcotic consumption and increased ambulation distances in the treatment group. The treatment group consumed approximately 170 mg morphine equivalents less than the control group between discharge and the 2-week postoperative visit. In addition, a significant difference was observed in the satisfaction scores in the treatment group.¹¹ Similarly, a meta-analysis by Raynor and colleagues¹² on randomized clinical trials comparing cryotherapy to a placebo group after anterior cruciate ligament reconstruction showed that cryotherapy is associated with significantly lower postoperative pain (P = .02), but demonstrated no difference in postoperative drainage (P = .23) or range of motion (P = .25).

Although multiple studies have been published regarding the efficacy of cryotherapy after knee surgery, very few studies have compared CC to conventional ICE after shoulder surgery. A prospective randomized trial was performed by Singh and colleagues¹³ to compare CC vs no ICE in open and arthroscopic shoulder surgery patients. Both the open and arthroscopic groups receiving CC demonstrated significant reductions in pain frequency and more restful sleep at the 7-day, 14-day, and 21-day intervals compared to the control group. However, they did not compare the commercial unit to ICE. In contrast, a study by Kraeutler and colleagues⁸ randomized 46 patients to receive either CC or ICE in the setting of arthroscopic shoulder surgery. Although no significant difference was observed in morphine equivalent dosage between the 2 groups, the CC group used more pain medication on every postoperative day during the first week after surgery. They found no difference between the 2 groups with regards to narcotic consumption or pain scores. The results of this study mirror those by Kraeutler and colleagues,⁸ demonstrating no difference in pain scores, sleep quality, or narcotic consumption.

Continue to: With rising costs in the US...

The major strengths of this study are the randomized design and multiple data points during the early postoperative period. However, there are several limitations. First, we did not objectively measure compliance of either therapy and relied only on a patient survey. Usage of the commercial CC unit in hours decreased over half between days 3 and 14. This occurred despite training on the application and specific instructions. We believe this reflects “real-world” usage, but it is possible that compliance affected our results. Second, all patients in this study had a single-shot interscalene block. While this is standard at our institution, it is possible that either CC or ICE would have a more significant effect in the absence of an interscalene block. Finally, we did not evaluate final outcomes in this study and therefore cannot determine if the final outcome was different between the 2 groups. Our goal was simply to evaluate the first 2 weeks following surgery, as this is the most painful period following TSA. 

CONCLUSION

There was no difference between CC and ICE in terms of pain control, quality of sleep, patient satisfaction, or narcotic consumption following TSA. CC may offer convenience advantages, but the increased cost associated with this type of unit may not be justified. 

ABSTRACT

The importance of cost control in total knee arthroplasty is increasing in the United States secondary to both changing economic realities of healthcare and the increasing prevalence of joint replacement.

Surgeons play a critical role in cost containment and may soon be incentivized to make cost-effective decisions under proposed gainsharing programs. The purpose of this study is to examine the cost-effectiveness of all-polyethylene tibial (APT) components and determine what difference in revision rate would make modular metal-backed tibial (MBT) implants a more cost-effective intervention.

Markov models were constructed using variable implant failure rates and previously published probabilities. Cost data were obtained from both our institution and published United States implant list prices, and modeled with a 3.0% discount rate. The decision tree was continued over a 20-year timeframe.

Using our institutional cost data and model assumptions with a 1.0% annual failure rate for MBT components, an annual failure rate of 1.6% for APT components would be required to achieve equivalency in cost. Over a 20-year period, a failure rate of >27% for the APT component would be necessary to achieve equivalent cost compared with the proposed failure rate of 18% with MBT components. A sensitivity analysis was performed with different assumptions for MBT annual failure rates.

Given our assumptions, the APT component is cost-saving if the excess cumulative revision rate increases by <9% in 20 years compared with that of the MBT implant. Surgeons, payers, and hospitals should consider this approach when evaluating implants. Consideration should also be given to the decreased utility associated with revision surgery.

Continue to: All-polythylene tibial implants...

All-polyethylene tibial (APT) implants have been available for use in total knee arthroplasty (TKA) for decades. Except for one particular implant design, APT implants have shown equivalent functional outcome and survivorship to metal-backed tibial (MBT) components.¹ Two recent systematic reviews have demonstrated no difference in durability or functional outcome between APT and MBT components.^1,2 Despite this data, APT components continue to be used uncommonly in the United States. Improved technical ease and the theoretical advantages of modularity are likely responsible for the continued popularity of MBT implants despite the fact that APT implants cost considerably less than their MBT counterparts.

The importance of cost control in TKA is increasing secondary to changing economic realities of healthcare and increasing prevalence of joint replacement. Payers are seeking ways to ensure quality care at more affordable reimbursement rates. Surgeons play a critical role in cost containment and may soon be incentivized to make cost-effective decisions under proposed gainsharing programs. Implants account for a substantial portion of hospital costs for knee replacement and have been suggested as an essential part of cost control.³ As such, surgeons in the United States will probably need to factor in value when selecting implants and be required to justify the additional cost of “premium” implants.

Given recent systemic reviews concluding both equivalent effectiveness and survivorship, the APT component would appear to be inherently cost-effective when compared with an MBT design. However, the degree to which this implant is cost-effective has been difficult to quantify. The purpose of this study is to take a novel approach to examine the cost-effectiveness of APT components by determining what theoretical difference in revision rate would make modular MBT implants a more cost-effective intervention using our institutional cost data.

MATERIALS AND METHODS

A Markov decision model was used to evaluate the cost-effectiveness of APT components.⁴ A Markov decision model is a mathematical framework for modeling decision making in situations where outcomes are partly random and partly under the control of a decision maker. They are powerful tools for determining the best solution from all feasible solutions to a given problem. A decision model was constructed (Figure 1) to depict patients with arthritis of the knee being treated with either APT or MBT implants in a fashion similar to previously published models.⁵ At each point of a patient’s health status in the 20 years following surgery, they are either considered well after total knee replacement, well after revision surgery, or dead. Patients transition through the decision tree and pass through different states according to the probability of each event occurring, a process that is discussed further below. A utility value, measured in quality-adjusted life years (QALYs), and a cost are assigned to every health state and both primary and revision procedures within the model. The model is designed to determine the maximum failure rate for which the APT is the more cost-effective option.

We assumed the age at the initial surgery to be 65 years. Age-specific mortality rates were taken from the 2007 United States Life Tables published by the Centers for Disease Control and Prevention.⁶ An additional probability of .007 of dying during the surgery or postoperative from the initial surgery and a probability of .011 from the revision was included.

Costs for the surgery were obtained from the University of Virginia’s billing department. We obtained the average cost for the diagnosis-related group in 2012. The cost of primary knee replacement was $17,578.06 with MBT implants. We subtracted institutional cost savings for the APT that could be achieved to obtain a cost of $16,272.10 for the APT. The cost of revision was $21,650.34 and assumed to be the same regardless of the type of initial surgery. A 3% discount rate was used.

The costs, QALYs, and probabilities were then used to compute cost-effectiveness ratios, or the cost per additional QALY, of the 2 options. Unlike previous models published in the orthopedic literature, we assumed a constant probability of revision for the MBT. We initially assumed a 1.0% probability of failure per year for the MBT implant. We then determined what revision rate for the APT would be necessary to be cost equivalent with the MBT. A sensitivity analysis was performed to examine the impact of varying assumptions regarding the rate of revision.

Continue to: Results...

RESULTS

Under our institutional cost data and model assumptions with a 1% annual failure rate for MBT implants, an annual failure rate of 1.6% for APT components would be required to achieve equivalency in cost. Over a 20-year period, a failure rate of >27% for the APT component would be necessary to achieve equivalent cost compared with the proposed failure rate of 18% with MBT components.

A two-way sensitivity analysis for probabilities of failure was performed to compare revision probabilities of the APT with those of MBT components. The preferred strategy graph is included in Figure 2. This graph shows how varying annual revision rates for both the APT and MBT would impact which option would be preferable. For example, on the graph, an annual failure rate of 1.6% for APT implants would be cost equivalent to a 0.1% annual failure rate for MBT implants at 20 years. A 2.0% annual failure rate for the APT would be equivalent to a 1.4% annual failure rate for the MBT, and a 2.5% failure rate for the APT would be equivalent to a 1.8% MBT failure rate. Holding the APT failure rate constant at 2.5%, any MBT failure rate <1.8% would make the MBT the more cost-effective option, whereas a failure rate >1.8% would make the MBT less cost-effective than the APT. For probability combinations that fall in the lower right area of Figure 2, the APT is preferable, and for probability combinations that fall in the upper left area, the MBT is preferable. The line separating the 2 areas is where 1 would be indifferent, such that the cost per additional QALY is the same for both procedures.

DISCUSSION

In light of the current economic climate and push for cost savings in the United States healthcare system, orthopedic surgeons must increasingly understand the realities of cost and the role it plays in the assessment of new technology. This concept is especially true of TKA as it becomes an increasingly common operative intervention. Utilizing cost savings techniques while ensuring quality outcomes is something that needs to be championed by healthcare providers.

Ideally, the introduction of a new medical technology that is more expensive than preexisting technology should lead to improved outcomes. Multiple randomized radiostereometric and clinical outcome studies looking at failure rates of APT compared with MBT have consistently suggested equivalence or superiority of the APT design when modern round-on-round implant designs are utilized.^7-17 Two recent systematic reviews demonstrated that APT components were equivalent to MBT components regarding both revision rates and clinical scores.^1,18 Given these results, it seems that the increased use of the APT design could save the healthcare system substantial amounts of money without compromising outcomes. For example, in 2006 Muller and colleagues^19. proposed a possible cost savings of approximately 39 million dollars per year across England and Wales, if just 50% of the 70,000 TKAs performed annually used APTs. Our study, which helps quantify the potential cost-effectiveness of the APT design in terms of revision rates, should help further support this debate and provide a framework for the evaluation of new technology.

It should be noted that the results of this current study are based on both assumptions and generalizations. Institutional cost data is known to vary widely among institutions and our conclusions regarding comparable revision rates would change with different cost inputs. We are also unable to take into account individual patients, surgeons, or specific implant factors. It is very difficult to place a price on quality-adjusted life years and negative repercussions with revision surgery. Furthermore, speaking specifically about surgical technique, each surgeon has his/her own preference when performing TKA. There is a lack of intraoperative flexibility when using monoblock tibial components that many surgeons may find undesirable. A surgeon is unable to adjust the thickness of the polyethylene insert after cementation of metal implants. Finally, we are aware that cost-effectiveness analyses cannot take the place of rational clinical decision making when evaluating an individual patient for TKA. Patient age, body mass index, and deformity are all factors that may dictate the use of MBTs in an attempt to improve outcomes.

The results of this analysis help quantify the cost-effectiveness of the APT. Given the additional cost, the MBT design would have to lower revision rates substantially when compared with the APT design to be considered cost-effective. Multiple clinical studies have not shown this to be the case. Further studies are required to help guide clinical decision making and define the role of APT components in TKA.

ABSTRACT

The importance of cost control in total knee arthroplasty is increasing in the United States secondary to both changing economic realities of healthcare and the increasing prevalence of joint replacement.

Surgeons play a critical role in cost containment and may soon be incentivized to make cost-effective decisions under proposed gainsharing programs. The purpose of this study is to examine the cost-effectiveness of all-polyethylene tibial (APT) components and determine what difference in revision rate would make modular metal-backed tibial (MBT) implants a more cost-effective intervention.

Markov models were constructed using variable implant failure rates and previously published probabilities. Cost data were obtained from both our institution and published United States implant list prices, and modeled with a 3.0% discount rate. The decision tree was continued over a 20-year timeframe.

Using our institutional cost data and model assumptions with a 1.0% annual failure rate for MBT components, an annual failure rate of 1.6% for APT components would be required to achieve equivalency in cost. Over a 20-year period, a failure rate of >27% for the APT component would be necessary to achieve equivalent cost compared with the proposed failure rate of 18% with MBT components. A sensitivity analysis was performed with different assumptions for MBT annual failure rates.

Given our assumptions, the APT component is cost-saving if the excess cumulative revision rate increases by <9% in 20 years compared with that of the MBT implant. Surgeons, payers, and hospitals should consider this approach when evaluating implants. Consideration should also be given to the decreased utility associated with revision surgery.

Continue to: All-polythylene tibial implants...

All-polyethylene tibial (APT) implants have been available for use in total knee arthroplasty (TKA) for decades. Except for one particular implant design, APT implants have shown equivalent functional outcome and survivorship to metal-backed tibial (MBT) components.¹ Two recent systematic reviews have demonstrated no difference in durability or functional outcome between APT and MBT components.^1,2 Despite this data, APT components continue to be used uncommonly in the United States. Improved technical ease and the theoretical advantages of modularity are likely responsible for the continued popularity of MBT implants despite the fact that APT implants cost considerably less than their MBT counterparts.

The importance of cost control in TKA is increasing secondary to changing economic realities of healthcare and increasing prevalence of joint replacement. Payers are seeking ways to ensure quality care at more affordable reimbursement rates. Surgeons play a critical role in cost containment and may soon be incentivized to make cost-effective decisions under proposed gainsharing programs. Implants account for a substantial portion of hospital costs for knee replacement and have been suggested as an essential part of cost control.³ As such, surgeons in the United States will probably need to factor in value when selecting implants and be required to justify the additional cost of “premium” implants.

Given recent systemic reviews concluding both equivalent effectiveness and survivorship, the APT component would appear to be inherently cost-effective when compared with an MBT design. However, the degree to which this implant is cost-effective has been difficult to quantify. The purpose of this study is to take a novel approach to examine the cost-effectiveness of APT components by determining what theoretical difference in revision rate would make modular MBT implants a more cost-effective intervention using our institutional cost data.

MATERIALS AND METHODS

A Markov decision model was used to evaluate the cost-effectiveness of APT components.⁴ A Markov decision model is a mathematical framework for modeling decision making in situations where outcomes are partly random and partly under the control of a decision maker. They are powerful tools for determining the best solution from all feasible solutions to a given problem. A decision model was constructed (Figure 1) to depict patients with arthritis of the knee being treated with either APT or MBT implants in a fashion similar to previously published models.⁵ At each point of a patient’s health status in the 20 years following surgery, they are either considered well after total knee replacement, well after revision surgery, or dead. Patients transition through the decision tree and pass through different states according to the probability of each event occurring, a process that is discussed further below. A utility value, measured in quality-adjusted life years (QALYs), and a cost are assigned to every health state and both primary and revision procedures within the model. The model is designed to determine the maximum failure rate for which the APT is the more cost-effective option.

We assumed the age at the initial surgery to be 65 years. Age-specific mortality rates were taken from the 2007 United States Life Tables published by the Centers for Disease Control and Prevention.⁶ An additional probability of .007 of dying during the surgery or postoperative from the initial surgery and a probability of .011 from the revision was included.

Costs for the surgery were obtained from the University of Virginia’s billing department. We obtained the average cost for the diagnosis-related group in 2012. The cost of primary knee replacement was $17,578.06 with MBT implants. We subtracted institutional cost savings for the APT that could be achieved to obtain a cost of $16,272.10 for the APT. The cost of revision was $21,650.34 and assumed to be the same regardless of the type of initial surgery. A 3% discount rate was used.

The costs, QALYs, and probabilities were then used to compute cost-effectiveness ratios, or the cost per additional QALY, of the 2 options. Unlike previous models published in the orthopedic literature, we assumed a constant probability of revision for the MBT. We initially assumed a 1.0% probability of failure per year for the MBT implant. We then determined what revision rate for the APT would be necessary to be cost equivalent with the MBT. A sensitivity analysis was performed to examine the impact of varying assumptions regarding the rate of revision.

Continue to: Results...

RESULTS

Under our institutional cost data and model assumptions with a 1% annual failure rate for MBT implants, an annual failure rate of 1.6% for APT components would be required to achieve equivalency in cost. Over a 20-year period, a failure rate of >27% for the APT component would be necessary to achieve equivalent cost compared with the proposed failure rate of 18% with MBT components.

A two-way sensitivity analysis for probabilities of failure was performed to compare revision probabilities of the APT with those of MBT components. The preferred strategy graph is included in Figure 2. This graph shows how varying annual revision rates for both the APT and MBT would impact which option would be preferable. For example, on the graph, an annual failure rate of 1.6% for APT implants would be cost equivalent to a 0.1% annual failure rate for MBT implants at 20 years. A 2.0% annual failure rate for the APT would be equivalent to a 1.4% annual failure rate for the MBT, and a 2.5% failure rate for the APT would be equivalent to a 1.8% MBT failure rate. Holding the APT failure rate constant at 2.5%, any MBT failure rate <1.8% would make the MBT the more cost-effective option, whereas a failure rate >1.8% would make the MBT less cost-effective than the APT. For probability combinations that fall in the lower right area of Figure 2, the APT is preferable, and for probability combinations that fall in the upper left area, the MBT is preferable. The line separating the 2 areas is where 1 would be indifferent, such that the cost per additional QALY is the same for both procedures.

DISCUSSION

In light of the current economic climate and push for cost savings in the United States healthcare system, orthopedic surgeons must increasingly understand the realities of cost and the role it plays in the assessment of new technology. This concept is especially true of TKA as it becomes an increasingly common operative intervention. Utilizing cost savings techniques while ensuring quality outcomes is something that needs to be championed by healthcare providers.

Ideally, the introduction of a new medical technology that is more expensive than preexisting technology should lead to improved outcomes. Multiple randomized radiostereometric and clinical outcome studies looking at failure rates of APT compared with MBT have consistently suggested equivalence or superiority of the APT design when modern round-on-round implant designs are utilized.^7-17 Two recent systematic reviews demonstrated that APT components were equivalent to MBT components regarding both revision rates and clinical scores.^1,18 Given these results, it seems that the increased use of the APT design could save the healthcare system substantial amounts of money without compromising outcomes. For example, in 2006 Muller and colleagues^19. proposed a possible cost savings of approximately 39 million dollars per year across England and Wales, if just 50% of the 70,000 TKAs performed annually used APTs. Our study, which helps quantify the potential cost-effectiveness of the APT design in terms of revision rates, should help further support this debate and provide a framework for the evaluation of new technology.

It should be noted that the results of this current study are based on both assumptions and generalizations. Institutional cost data is known to vary widely among institutions and our conclusions regarding comparable revision rates would change with different cost inputs. We are also unable to take into account individual patients, surgeons, or specific implant factors. It is very difficult to place a price on quality-adjusted life years and negative repercussions with revision surgery. Furthermore, speaking specifically about surgical technique, each surgeon has his/her own preference when performing TKA. There is a lack of intraoperative flexibility when using monoblock tibial components that many surgeons may find undesirable. A surgeon is unable to adjust the thickness of the polyethylene insert after cementation of metal implants. Finally, we are aware that cost-effectiveness analyses cannot take the place of rational clinical decision making when evaluating an individual patient for TKA. Patient age, body mass index, and deformity are all factors that may dictate the use of MBTs in an attempt to improve outcomes.

The results of this analysis help quantify the cost-effectiveness of the APT. Given the additional cost, the MBT design would have to lower revision rates substantially when compared with the APT design to be considered cost-effective. Multiple clinical studies have not shown this to be the case. Further studies are required to help guide clinical decision making and define the role of APT components in TKA.

ABSTRACT

The importance of cost control in total knee arthroplasty is increasing in the United States secondary to both changing economic realities of healthcare and the increasing prevalence of joint replacement.

Surgeons play a critical role in cost containment and may soon be incentivized to make cost-effective decisions under proposed gainsharing programs. The purpose of this study is to examine the cost-effectiveness of all-polyethylene tibial (APT) components and determine what difference in revision rate would make modular metal-backed tibial (MBT) implants a more cost-effective intervention.

Markov models were constructed using variable implant failure rates and previously published probabilities. Cost data were obtained from both our institution and published United States implant list prices, and modeled with a 3.0% discount rate. The decision tree was continued over a 20-year timeframe.

Using our institutional cost data and model assumptions with a 1.0% annual failure rate for MBT components, an annual failure rate of 1.6% for APT components would be required to achieve equivalency in cost. Over a 20-year period, a failure rate of >27% for the APT component would be necessary to achieve equivalent cost compared with the proposed failure rate of 18% with MBT components. A sensitivity analysis was performed with different assumptions for MBT annual failure rates.

Given our assumptions, the APT component is cost-saving if the excess cumulative revision rate increases by <9% in 20 years compared with that of the MBT implant. Surgeons, payers, and hospitals should consider this approach when evaluating implants. Consideration should also be given to the decreased utility associated with revision surgery.

Continue to: All-polythylene tibial implants...

All-polyethylene tibial (APT) implants have been available for use in total knee arthroplasty (TKA) for decades. Except for one particular implant design, APT implants have shown equivalent functional outcome and survivorship to metal-backed tibial (MBT) components.¹ Two recent systematic reviews have demonstrated no difference in durability or functional outcome between APT and MBT components.^1,2 Despite this data, APT components continue to be used uncommonly in the United States. Improved technical ease and the theoretical advantages of modularity are likely responsible for the continued popularity of MBT implants despite the fact that APT implants cost considerably less than their MBT counterparts.

The importance of cost control in TKA is increasing secondary to changing economic realities of healthcare and increasing prevalence of joint replacement. Payers are seeking ways to ensure quality care at more affordable reimbursement rates. Surgeons play a critical role in cost containment and may soon be incentivized to make cost-effective decisions under proposed gainsharing programs. Implants account for a substantial portion of hospital costs for knee replacement and have been suggested as an essential part of cost control.³ As such, surgeons in the United States will probably need to factor in value when selecting implants and be required to justify the additional cost of “premium” implants.

Given recent systemic reviews concluding both equivalent effectiveness and survivorship, the APT component would appear to be inherently cost-effective when compared with an MBT design. However, the degree to which this implant is cost-effective has been difficult to quantify. The purpose of this study is to take a novel approach to examine the cost-effectiveness of APT components by determining what theoretical difference in revision rate would make modular MBT implants a more cost-effective intervention using our institutional cost data.

MATERIALS AND METHODS

A Markov decision model was used to evaluate the cost-effectiveness of APT components.⁴ A Markov decision model is a mathematical framework for modeling decision making in situations where outcomes are partly random and partly under the control of a decision maker. They are powerful tools for determining the best solution from all feasible solutions to a given problem. A decision model was constructed (Figure 1) to depict patients with arthritis of the knee being treated with either APT or MBT implants in a fashion similar to previously published models.⁵ At each point of a patient’s health status in the 20 years following surgery, they are either considered well after total knee replacement, well after revision surgery, or dead. Patients transition through the decision tree and pass through different states according to the probability of each event occurring, a process that is discussed further below. A utility value, measured in quality-adjusted life years (QALYs), and a cost are assigned to every health state and both primary and revision procedures within the model. The model is designed to determine the maximum failure rate for which the APT is the more cost-effective option.

We assumed the age at the initial surgery to be 65 years. Age-specific mortality rates were taken from the 2007 United States Life Tables published by the Centers for Disease Control and Prevention.⁶ An additional probability of .007 of dying during the surgery or postoperative from the initial surgery and a probability of .011 from the revision was included.

Costs for the surgery were obtained from the University of Virginia’s billing department. We obtained the average cost for the diagnosis-related group in 2012. The cost of primary knee replacement was $17,578.06 with MBT implants. We subtracted institutional cost savings for the APT that could be achieved to obtain a cost of $16,272.10 for the APT. The cost of revision was $21,650.34 and assumed to be the same regardless of the type of initial surgery. A 3% discount rate was used.

The costs, QALYs, and probabilities were then used to compute cost-effectiveness ratios, or the cost per additional QALY, of the 2 options. Unlike previous models published in the orthopedic literature, we assumed a constant probability of revision for the MBT. We initially assumed a 1.0% probability of failure per year for the MBT implant. We then determined what revision rate for the APT would be necessary to be cost equivalent with the MBT. A sensitivity analysis was performed to examine the impact of varying assumptions regarding the rate of revision.

Continue to: Results...

RESULTS

Under our institutional cost data and model assumptions with a 1% annual failure rate for MBT implants, an annual failure rate of 1.6% for APT components would be required to achieve equivalency in cost. Over a 20-year period, a failure rate of >27% for the APT component would be necessary to achieve equivalent cost compared with the proposed failure rate of 18% with MBT components.

A two-way sensitivity analysis for probabilities of failure was performed to compare revision probabilities of the APT with those of MBT components. The preferred strategy graph is included in Figure 2. This graph shows how varying annual revision rates for both the APT and MBT would impact which option would be preferable. For example, on the graph, an annual failure rate of 1.6% for APT implants would be cost equivalent to a 0.1% annual failure rate for MBT implants at 20 years. A 2.0% annual failure rate for the APT would be equivalent to a 1.4% annual failure rate for the MBT, and a 2.5% failure rate for the APT would be equivalent to a 1.8% MBT failure rate. Holding the APT failure rate constant at 2.5%, any MBT failure rate <1.8% would make the MBT the more cost-effective option, whereas a failure rate >1.8% would make the MBT less cost-effective than the APT. For probability combinations that fall in the lower right area of Figure 2, the APT is preferable, and for probability combinations that fall in the upper left area, the MBT is preferable. The line separating the 2 areas is where 1 would be indifferent, such that the cost per additional QALY is the same for both procedures.

DISCUSSION

In light of the current economic climate and push for cost savings in the United States healthcare system, orthopedic surgeons must increasingly understand the realities of cost and the role it plays in the assessment of new technology. This concept is especially true of TKA as it becomes an increasingly common operative intervention. Utilizing cost savings techniques while ensuring quality outcomes is something that needs to be championed by healthcare providers.

Ideally, the introduction of a new medical technology that is more expensive than preexisting technology should lead to improved outcomes. Multiple randomized radiostereometric and clinical outcome studies looking at failure rates of APT compared with MBT have consistently suggested equivalence or superiority of the APT design when modern round-on-round implant designs are utilized.^7-17 Two recent systematic reviews demonstrated that APT components were equivalent to MBT components regarding both revision rates and clinical scores.^1,18 Given these results, it seems that the increased use of the APT design could save the healthcare system substantial amounts of money without compromising outcomes. For example, in 2006 Muller and colleagues^19. proposed a possible cost savings of approximately 39 million dollars per year across England and Wales, if just 50% of the 70,000 TKAs performed annually used APTs. Our study, which helps quantify the potential cost-effectiveness of the APT design in terms of revision rates, should help further support this debate and provide a framework for the evaluation of new technology.

It should be noted that the results of this current study are based on both assumptions and generalizations. Institutional cost data is known to vary widely among institutions and our conclusions regarding comparable revision rates would change with different cost inputs. We are also unable to take into account individual patients, surgeons, or specific implant factors. It is very difficult to place a price on quality-adjusted life years and negative repercussions with revision surgery. Furthermore, speaking specifically about surgical technique, each surgeon has his/her own preference when performing TKA. There is a lack of intraoperative flexibility when using monoblock tibial components that many surgeons may find undesirable. A surgeon is unable to adjust the thickness of the polyethylene insert after cementation of metal implants. Finally, we are aware that cost-effectiveness analyses cannot take the place of rational clinical decision making when evaluating an individual patient for TKA. Patient age, body mass index, and deformity are all factors that may dictate the use of MBTs in an attempt to improve outcomes.

The results of this analysis help quantify the cost-effectiveness of the APT. Given the additional cost, the MBT design would have to lower revision rates substantially when compared with the APT design to be considered cost-effective. Multiple clinical studies have not shown this to be the case. Further studies are required to help guide clinical decision making and define the role of APT components in TKA.

ABSTRACT

Lesser tuberosity osteotomy (LTO) and subscapularis tenotomy (ST) are used for takedown of the subscapularis during shoulder arthroplasty. LTO offers the theoretical but unproven benefit of improved healing and function of the subscapularis. However, humeral stem subsidence and loosening may be greater when osteotomy is performed, which may compromise functional outcomes. Our hypothesis is that no difference in proximal collar press-fit humeral stem subsidence or loosening exists, with no impairment of functional outcomes using the LTO technique.

During the surgical approach for total shoulder arthroplasty (TSA), the subscapularis is taken down for adequate exposure to the glenohumeral joint. Various methods are available for taking down the subscapularis, including lesser tuberosity osteotomy (LTO) and a subscapularis tenotomy (ST). LTO offers the theoretical but unproven benefit of improved healing and function of the subscapularis secondary to bone-to-bone healing. One concern, however, is that humeral stem subsidence may be greater when an osteotomy is performed owing to compromise of metaphyseal cortical bone, which may compromise functional outcomes. The humeral stem design may also influence subsidence when metaphyseal bone proximally is compromised. This is a concern in both metaphyseal and diaphyseal fitting stems. Metaphyseal collars on diaphyseal fitting stems rely on adequate bone stock in the metaphysis to provide the additional support needed. Also, posterior subluxation remains a challenge in shoulder arthroplasty. The integrity of the subscapularis is important in prevention of posterior subluxation.¹ To our knowledge, no study to date has directly compared differences in humeral stem subsidence, loosening, or posterior subluxation between LTO and ST techniques with any humeral stem design. Our hypothesis is that no difference in proximal collar press-fit humeral stem subsidence or loosening exists, with no impairment of functional outcomes using the LTO technique. We also hypothesize that no difference in posterior subluxation exists between LTO and ST techniques.

MATERIALS AND METHODS

INCLUSION CRITERIA

Consecutive patients with a minimum of 12 months of radiographic follow-up were selected from 2007 to 2010 after TSA was performed by 1 of the senior authors (Dr. Miller and Dr. Voloshin). Study patients underwent primary TSA for primary osteoarthritis or rheumatoid arthritis.

EXCLUSION CRITERIA

Patients were excluded if they underwent TSA for posttraumatic glenohumeral arthritis, hemiarthroplasty, or osteonecrosis. Patients were also excluded if a rotator cuff tear was discovered intraoperatively or if they had a history of a rotator cuff repair. Additional exclusion criteria included postoperative trauma to the operative shoulder, postoperative infection, extensive documentation of chronic pain, and underlying neurologic disorder (eg, Parkinson disease, dystonia). Patients with a history of diabetes mellitus were not excluded.

SURGICAL TECHNIQUE

All patients underwent TSA via a deltopectoral approach in a modified beach chair position. Biceps tendons were tenodesed at the level of the pectoralis major. All patients received the same proximal collar press-fit implant (Bigliani-Flatow; Zimmer Biomet). These stems provide rotational stability in the metaphyseal segment via fins, vertical stability with the proximal collar, and distal fixation via an interference fit. All parts of the procedure were performed in similar fashion with the exception of ST vs LTO (Figures 1A-1D). 

Continue to: LTO was performed as the primary...

LESSER TUBEROSITY OSTEOTOMY

LTO was performed as the primary or preferred technique of 1 surgeon. After completion of the biceps tenodesis, the lesser tuberosity is reflected off with the subscapularis intact using an osteotome. After placement of the press-fit humeral stem, the LTO is repaired using No. 5 Ethibond Excel sutures (Ethicon) passed through previously created bone tunnels in the greater tuberosity. These sutures are tied over metal buttons over the lateral cortex of the greater tuberosity. Last, the lateral corner of the rotator interval is repaired using a single No. 2 FiberWire (Arthrex).²

SUBSCAPULARIS TENOTOMY

ST is the preferred surgical technique of the second surgeon. After a biceps tenodesis, the subscapularis tendon is released from the lesser tuberosity at the margin of the bicipital groove. Through careful dissection, a single flap including the underlying capsule is created and reflected medially to the level of the coracoid. After placement of the press-fit humeral stem and humeral head, the subscapularis is repaired back in place through previous bone tunnels and with a No. 5 Ethibond Excel suture under the appropriate tension. Then, the lateral corner of the rotator interval is closed using a single No. 2 Ethibond Excel suture in a figure-of-eight fashion.²

RADIOGRAPHIC ANALYSIS

The primary variables analyzed were subsidence and loosening. Additional variables, including humeral-acromial distance (HAD) and subluxation index, were also analyzed to assess for any additional impact caused by subsidence or loosening.³ All radiographic measurements were taken from the Grashey (true anteroposterior) view, except subluxation index, which was calculated using the axillary view. All radiographic measurements were completed by 3 independent reviewers. All radiographs were completed in a consistent manner according to postoperative protocols.

HAD was measured preoperatively, immediately postoperatively, and at final follow-up at a minimum of 1 year. The HAD was measured from the lowest point on the acromion to the humerus using a perpendicular line (Figure 2).

Subsidence of the prosthesis was calculated by determining the difference between immediate postoperative heights of the prosthesis in comparison to the value of the final follow-up films. To calculate the height, 2 lines were drawn, 1 line was drawn perpendicular to the top of the prosthetic head and 1 perpendicular to the top of the greater tuberosity (Figure 3). 

Continue to: Posterior subluxation is indicated...

The humeral stems were evaluated for loosening by assessing for lucency on final radiographic follow-up films. These were evaluated in a zonal fashion as demonstrated by Sanchez-Sotelo and colleagues⁴ and in Figure 5. 

FUNCTIONAL OUTCOME EVALUATION

Before clinical evaluation, each study patient completed the Western Ontario Osteoarthritis of the Shoulder (WOOS) index; the Disabilities of the Hand, Arm and Shoulder (DASH) questionnaire, and the pain and function sections of the Constant score. The functional outcomes scores were captured postoperatively from October to November 2011. The WOOS is a validated outcome measure specific to osteoarthritis of the shoulder and has been used in prior studies evaluating outcomes of TSA.^5-7 Previous studies have determined that the minimal clinically important difference for the WOOS score is 15 on a normalized 0 to 100 scale (100 being the best). The DASH score is a validated outcome measure for disorders of the upper extremity but is not specific to osteoarthritis of the shoulder.⁸ The Constant score is a validated outcome measure for a number of shoulder disorders, including TSA.^9,10

STATISTICAL ANALYSIS

Statistical analyses were completed by a trained biostatistician. A power analysis was calculated using the noninferiority test to determine if adequate data had been obtained for this study. This was calculated by using previously accepted data demonstrating a statistically significant difference for subsidence and HAD. The data from these studies were used to make assumptions regarding accepted standard deviations and noninferiority margins, as calculated from the mean values of the 2 groups analyzed in each respective study.^4,11 This analysis demonstrated power of 0.97 and 0.85 for the subsidence and HAD, respectively, given the current sample sizes. Intraclass coefficients were calculated to evaluate the measurements obtained during the radiographic analysis to determine the interrater agreement. Two samples’ t tests were calculated for the variables analyzed, along with P values and means.

RESULTS

DEMOGRAPHICS

A total of 51 consecutive patients were retrospectively selected for analysis. Of these, 16 patients were excluded from the study because they had <9 months of radiographic follow-up and were unavailable for further follow-up evaluation. Of the remaining 35 patients available for analysis, 4 patients had bilateral TSA, providing 39 shoulders for evaluation. Demographic characteristics of the study cohort are reported in Table 1.

  Fifteen patients underwent LTO, and 24 underwent ST. One patient underwent a tenotomy of the right shoulder and LTO of the left shoulder. Three LTOs were performed by the surgeon who primarily performed ST, owing to potential benefits of LTO. He eventually returned to his preferred technique of ST because of surgeon preference. Three ST procedures were completed by the surgeon who typically performed LTO at the start of the series prior to establishing LTO as his preferred technique. There was no significant difference between the study populations in terms of age, follow-up, male-to-female ratio, hand dominance, and primary diagnosis of osteoarthritis vs rheumatoid arthritis.

Continue to: There was no significant difference...

RADIOGRAPHIC DATA

There was no significant difference in preoperative HAD between the LTO and ST groups (9.5 ± 2.4 mm vs 10.9 ± 2.7 mm, P = .11). The immediate postoperative HAD was statistically significant between the LTO and ST groups (11.9 ± 3.7 mm vs 15.9 ± 4.5 mm, P = .005). There was as statistically significant difference noted in the final follow-up films between the LTO and ST groups (11.8 ± 3.2 mm vs 14.5 ± 3.9 mm, P = .025) (Table 2). 

Abbreviations: LTO, lesser tuberosity osteotomy; ST, subscapularis tenotomy.

There were no statistically significant differences found in subsidence between LTO and ST groups at final follow-up (2.8 mm ± 3.1 mm vs 2.5 mm ± 3.1 mm, P = .72) (Table 2). No statistically significant difference was noted in the subluxation index between the LTO and ST groups (0.55% ± .06% vs 0.54% ± 0.07%, P = .45), but there was a statistically significant difference noted postoperatively between the LTO and ST groups (0.55% ± 0.09% vs .48% ± 0.05%, P = .015) (Table 2).

Two stems were noted to have lucent lines >2 mm, both within the ST cohort. Each had 1 stem zone >2 mm, 1 in zone 7, and 1 in zone 4. No statistically significant difference was identified between the LTO and ST groups (0/15 vs 2/24, P = .51) (Table 2).

FUNCTIONAL OUTCOMES

Study patients were evaluated using functional outcome scores, including the Constant, WOOS, and DASH scores (Table 3). 

Abbreviations: DASH, disabilities of the arm, shoulder and hand; WOOS, Western Ontario Osteoarthritis of the Shoulder.

No statistically significant differences were noted in the DASH scores (8.4 ± 6.6 vs 13.8 ± 4.9, P = .13) or Constant scores (83.3 ± 9.1 vs 81.8 ± 10.1, P = .64) between the LTO and ST cohorts. There was a statistically significant difference between the WOOS scores (93.3 ± 5.3 vs 81.5 ± 20.8, P = .013). Because separate radiographic reviews were done by 3 independent personnel at 3 different times, it was important to ensure agreement among the reviewers. This was compared using the intraclass correlation coefficients. In the statistical analysis completed, the intraclass coefficients showed the 3 reviewers agreed with each other throughout the radiographic analysis (Table 4).

Abbreviations: CI, confidence interval; HAD, humeral acromial distance; ICC, intraclass correlation coefficient; SI, subluxation index.

DISCUSSION

At final follow-up, we identified no statistically significant difference between the LTO and ST patients in subsidence, lucent lines >2 mm, or functional outcomes (Constant and DASH scores) in patients who underwent TSA with the same proximal collar press-fit humeral stem. In regard to the functional outcome scores, although the WOOS score was statistically significant (P = .013) between the LTO and ST cohorts, we do not feel that this is clinically relevant because it does not reach the minimal clinically important difference threshold of 15 points.⁸

A statistically significant difference was noted in postoperative subluxation index but was not clinically relevant, because the values between the LTO and ST groups (0.55 vs 0.48) still showed a centered humeral head. Gerber and colleagues³ discussed using a value of 0.65 as a measure of posterior humeral head subluxation, whereas Walch and colleagues¹² defined posterior humeral head subluxation as a value >0.55. On the basis of these numbers, the values obtained in this study demonstrated that the postoperative values were still centered on the glenoid, and therefore were not clinically significant.^3,12

Continue to: In regard to HAD, there...

Studies have shown a concern regarding the integrity of the subscapularis after tenotomy or peel used in TSA with abnormal subscapularis function.^14,15 Miller and colleagues¹⁵ reported 41 patients, nearly two-thirds, of whom described subscapularis dysfunction. Those authors’ response to the poor clinical outcomes was to remove a fleck of bone with the tendon to achieve “bone-to-bone” healing.¹⁴ Gerber and colleagues¹⁶ reported on a series of patients using LTO and repair in TSA with 75% and 89% intact subscapularis function on clinical testing.¹⁶ Studies by Qureshi and colleagues¹⁷ and Scalise and colleagues¹⁸ showed similar results after LTO. Biomechanical studies have shown mixed results. Ponce and colleagues¹⁹ showed biomechanically superior results for LTO in comparison to the various repair techniques for ST. In another study, Giuseffi and colleagues²⁰ showed no difference in LTO vs ST during biomechanical testing. In response to the increased concern regarding subscapularis integrity, Caplan and colleagues²¹ reported on 45 arthroplasties in 43 patients with improved postoperative testing with intact subscapularis testing in 90% to 100% of patients. A level 1 randomized control trial conducted by Lapner and colleagues²² did not demonstrate any clear clinical advantage of LTO vs ST. Controversy still exists regarding which is the preferred technique for TSA.

Sanchez-Sotelo and colleagues⁴ evaluated uncemented humeral components in 72 patients who underwent TSA. They found a humeral component was at risk for loosening if a radiolucent line ≥2 mm was present in at least 3 radiographic zones. They also evaluated tilt or subsidence by measurement and whether the components were observed to have changed. Their measured values correlated with their observed values. That study provided a benchmark for evaluation of loosening and subsidence used during this study.⁴ Although radiographic follow-up is limited in this study, we feel that any potential subsidence secondary to use of the LTO technique would be radiographically apparent at 1 year. There were 16 patients without adequate radiographic follow-up included in the study. However, we feel that this was not a large concern, because the study was adequately powered with the patients available to determine a difference based on subsidence.

CONCLUSION

We found no difference in subsidence, lucent lines >2 mm, posterior subluxation, and the Constant and DASH functional outcome scores when we compared TSA performed by a LTO with an ST technique with proximal collar press-fit humeral stem. These data cannot be extrapolated to metaphyseal fit stems, which may exhibit different settling characteristics in the setting of the LTO technique.

This paper will be judged for the Resident Writer’s Award.

ABSTRACT

Lesser tuberosity osteotomy (LTO) and subscapularis tenotomy (ST) are used for takedown of the subscapularis during shoulder arthroplasty. LTO offers the theoretical but unproven benefit of improved healing and function of the subscapularis. However, humeral stem subsidence and loosening may be greater when osteotomy is performed, which may compromise functional outcomes. Our hypothesis is that no difference in proximal collar press-fit humeral stem subsidence or loosening exists, with no impairment of functional outcomes using the LTO technique.

During the surgical approach for total shoulder arthroplasty (TSA), the subscapularis is taken down for adequate exposure to the glenohumeral joint. Various methods are available for taking down the subscapularis, including lesser tuberosity osteotomy (LTO) and a subscapularis tenotomy (ST). LTO offers the theoretical but unproven benefit of improved healing and function of the subscapularis secondary to bone-to-bone healing. One concern, however, is that humeral stem subsidence may be greater when an osteotomy is performed owing to compromise of metaphyseal cortical bone, which may compromise functional outcomes. The humeral stem design may also influence subsidence when metaphyseal bone proximally is compromised. This is a concern in both metaphyseal and diaphyseal fitting stems. Metaphyseal collars on diaphyseal fitting stems rely on adequate bone stock in the metaphysis to provide the additional support needed. Also, posterior subluxation remains a challenge in shoulder arthroplasty. The integrity of the subscapularis is important in prevention of posterior subluxation.¹ To our knowledge, no study to date has directly compared differences in humeral stem subsidence, loosening, or posterior subluxation between LTO and ST techniques with any humeral stem design. Our hypothesis is that no difference in proximal collar press-fit humeral stem subsidence or loosening exists, with no impairment of functional outcomes using the LTO technique. We also hypothesize that no difference in posterior subluxation exists between LTO and ST techniques.

MATERIALS AND METHODS

INCLUSION CRITERIA

Consecutive patients with a minimum of 12 months of radiographic follow-up were selected from 2007 to 2010 after TSA was performed by 1 of the senior authors (Dr. Miller and Dr. Voloshin). Study patients underwent primary TSA for primary osteoarthritis or rheumatoid arthritis.

EXCLUSION CRITERIA

Patients were excluded if they underwent TSA for posttraumatic glenohumeral arthritis, hemiarthroplasty, or osteonecrosis. Patients were also excluded if a rotator cuff tear was discovered intraoperatively or if they had a history of a rotator cuff repair. Additional exclusion criteria included postoperative trauma to the operative shoulder, postoperative infection, extensive documentation of chronic pain, and underlying neurologic disorder (eg, Parkinson disease, dystonia). Patients with a history of diabetes mellitus were not excluded.

SURGICAL TECHNIQUE

All patients underwent TSA via a deltopectoral approach in a modified beach chair position. Biceps tendons were tenodesed at the level of the pectoralis major. All patients received the same proximal collar press-fit implant (Bigliani-Flatow; Zimmer Biomet). These stems provide rotational stability in the metaphyseal segment via fins, vertical stability with the proximal collar, and distal fixation via an interference fit. All parts of the procedure were performed in similar fashion with the exception of ST vs LTO (Figures 1A-1D). 

Continue to: LTO was performed as the primary...

LESSER TUBEROSITY OSTEOTOMY

LTO was performed as the primary or preferred technique of 1 surgeon. After completion of the biceps tenodesis, the lesser tuberosity is reflected off with the subscapularis intact using an osteotome. After placement of the press-fit humeral stem, the LTO is repaired using No. 5 Ethibond Excel sutures (Ethicon) passed through previously created bone tunnels in the greater tuberosity. These sutures are tied over metal buttons over the lateral cortex of the greater tuberosity. Last, the lateral corner of the rotator interval is repaired using a single No. 2 FiberWire (Arthrex).²

SUBSCAPULARIS TENOTOMY

ST is the preferred surgical technique of the second surgeon. After a biceps tenodesis, the subscapularis tendon is released from the lesser tuberosity at the margin of the bicipital groove. Through careful dissection, a single flap including the underlying capsule is created and reflected medially to the level of the coracoid. After placement of the press-fit humeral stem and humeral head, the subscapularis is repaired back in place through previous bone tunnels and with a No. 5 Ethibond Excel suture under the appropriate tension. Then, the lateral corner of the rotator interval is closed using a single No. 2 Ethibond Excel suture in a figure-of-eight fashion.²

RADIOGRAPHIC ANALYSIS

The primary variables analyzed were subsidence and loosening. Additional variables, including humeral-acromial distance (HAD) and subluxation index, were also analyzed to assess for any additional impact caused by subsidence or loosening.³ All radiographic measurements were taken from the Grashey (true anteroposterior) view, except subluxation index, which was calculated using the axillary view. All radiographic measurements were completed by 3 independent reviewers. All radiographs were completed in a consistent manner according to postoperative protocols.

HAD was measured preoperatively, immediately postoperatively, and at final follow-up at a minimum of 1 year. The HAD was measured from the lowest point on the acromion to the humerus using a perpendicular line (Figure 2).

Subsidence of the prosthesis was calculated by determining the difference between immediate postoperative heights of the prosthesis in comparison to the value of the final follow-up films. To calculate the height, 2 lines were drawn, 1 line was drawn perpendicular to the top of the prosthetic head and 1 perpendicular to the top of the greater tuberosity (Figure 3). 

Continue to: Posterior subluxation is indicated...

The humeral stems were evaluated for loosening by assessing for lucency on final radiographic follow-up films. These were evaluated in a zonal fashion as demonstrated by Sanchez-Sotelo and colleagues⁴ and in Figure 5. 

FUNCTIONAL OUTCOME EVALUATION

Before clinical evaluation, each study patient completed the Western Ontario Osteoarthritis of the Shoulder (WOOS) index; the Disabilities of the Hand, Arm and Shoulder (DASH) questionnaire, and the pain and function sections of the Constant score. The functional outcomes scores were captured postoperatively from October to November 2011. The WOOS is a validated outcome measure specific to osteoarthritis of the shoulder and has been used in prior studies evaluating outcomes of TSA.^5-7 Previous studies have determined that the minimal clinically important difference for the WOOS score is 15 on a normalized 0 to 100 scale (100 being the best). The DASH score is a validated outcome measure for disorders of the upper extremity but is not specific to osteoarthritis of the shoulder.⁸ The Constant score is a validated outcome measure for a number of shoulder disorders, including TSA.^9,10

STATISTICAL ANALYSIS

Statistical analyses were completed by a trained biostatistician. A power analysis was calculated using the noninferiority test to determine if adequate data had been obtained for this study. This was calculated by using previously accepted data demonstrating a statistically significant difference for subsidence and HAD. The data from these studies were used to make assumptions regarding accepted standard deviations and noninferiority margins, as calculated from the mean values of the 2 groups analyzed in each respective study.^4,11 This analysis demonstrated power of 0.97 and 0.85 for the subsidence and HAD, respectively, given the current sample sizes. Intraclass coefficients were calculated to evaluate the measurements obtained during the radiographic analysis to determine the interrater agreement. Two samples’ t tests were calculated for the variables analyzed, along with P values and means.

RESULTS

DEMOGRAPHICS

A total of 51 consecutive patients were retrospectively selected for analysis. Of these, 16 patients were excluded from the study because they had <9 months of radiographic follow-up and were unavailable for further follow-up evaluation. Of the remaining 35 patients available for analysis, 4 patients had bilateral TSA, providing 39 shoulders for evaluation. Demographic characteristics of the study cohort are reported in Table 1.

  Fifteen patients underwent LTO, and 24 underwent ST. One patient underwent a tenotomy of the right shoulder and LTO of the left shoulder. Three LTOs were performed by the surgeon who primarily performed ST, owing to potential benefits of LTO. He eventually returned to his preferred technique of ST because of surgeon preference. Three ST procedures were completed by the surgeon who typically performed LTO at the start of the series prior to establishing LTO as his preferred technique. There was no significant difference between the study populations in terms of age, follow-up, male-to-female ratio, hand dominance, and primary diagnosis of osteoarthritis vs rheumatoid arthritis.

Continue to: There was no significant difference...

RADIOGRAPHIC DATA

There was no significant difference in preoperative HAD between the LTO and ST groups (9.5 ± 2.4 mm vs 10.9 ± 2.7 mm, P = .11). The immediate postoperative HAD was statistically significant between the LTO and ST groups (11.9 ± 3.7 mm vs 15.9 ± 4.5 mm, P = .005). There was as statistically significant difference noted in the final follow-up films between the LTO and ST groups (11.8 ± 3.2 mm vs 14.5 ± 3.9 mm, P = .025) (Table 2). 

Abbreviations: LTO, lesser tuberosity osteotomy; ST, subscapularis tenotomy.

There were no statistically significant differences found in subsidence between LTO and ST groups at final follow-up (2.8 mm ± 3.1 mm vs 2.5 mm ± 3.1 mm, P = .72) (Table 2). No statistically significant difference was noted in the subluxation index between the LTO and ST groups (0.55% ± .06% vs 0.54% ± 0.07%, P = .45), but there was a statistically significant difference noted postoperatively between the LTO and ST groups (0.55% ± 0.09% vs .48% ± 0.05%, P = .015) (Table 2).

Two stems were noted to have lucent lines >2 mm, both within the ST cohort. Each had 1 stem zone >2 mm, 1 in zone 7, and 1 in zone 4. No statistically significant difference was identified between the LTO and ST groups (0/15 vs 2/24, P = .51) (Table 2).

FUNCTIONAL OUTCOMES

Study patients were evaluated using functional outcome scores, including the Constant, WOOS, and DASH scores (Table 3). 

Abbreviations: DASH, disabilities of the arm, shoulder and hand; WOOS, Western Ontario Osteoarthritis of the Shoulder.

No statistically significant differences were noted in the DASH scores (8.4 ± 6.6 vs 13.8 ± 4.9, P = .13) or Constant scores (83.3 ± 9.1 vs 81.8 ± 10.1, P = .64) between the LTO and ST cohorts. There was a statistically significant difference between the WOOS scores (93.3 ± 5.3 vs 81.5 ± 20.8, P = .013). Because separate radiographic reviews were done by 3 independent personnel at 3 different times, it was important to ensure agreement among the reviewers. This was compared using the intraclass correlation coefficients. In the statistical analysis completed, the intraclass coefficients showed the 3 reviewers agreed with each other throughout the radiographic analysis (Table 4).

Abbreviations: CI, confidence interval; HAD, humeral acromial distance; ICC, intraclass correlation coefficient; SI, subluxation index.

DISCUSSION

At final follow-up, we identified no statistically significant difference between the LTO and ST patients in subsidence, lucent lines >2 mm, or functional outcomes (Constant and DASH scores) in patients who underwent TSA with the same proximal collar press-fit humeral stem. In regard to the functional outcome scores, although the WOOS score was statistically significant (P = .013) between the LTO and ST cohorts, we do not feel that this is clinically relevant because it does not reach the minimal clinically important difference threshold of 15 points.⁸

A statistically significant difference was noted in postoperative subluxation index but was not clinically relevant, because the values between the LTO and ST groups (0.55 vs 0.48) still showed a centered humeral head. Gerber and colleagues³ discussed using a value of 0.65 as a measure of posterior humeral head subluxation, whereas Walch and colleagues¹² defined posterior humeral head subluxation as a value >0.55. On the basis of these numbers, the values obtained in this study demonstrated that the postoperative values were still centered on the glenoid, and therefore were not clinically significant.^3,12

Continue to: In regard to HAD, there...

Studies have shown a concern regarding the integrity of the subscapularis after tenotomy or peel used in TSA with abnormal subscapularis function.^14,15 Miller and colleagues¹⁵ reported 41 patients, nearly two-thirds, of whom described subscapularis dysfunction. Those authors’ response to the poor clinical outcomes was to remove a fleck of bone with the tendon to achieve “bone-to-bone” healing.¹⁴ Gerber and colleagues¹⁶ reported on a series of patients using LTO and repair in TSA with 75% and 89% intact subscapularis function on clinical testing.¹⁶ Studies by Qureshi and colleagues¹⁷ and Scalise and colleagues¹⁸ showed similar results after LTO. Biomechanical studies have shown mixed results. Ponce and colleagues¹⁹ showed biomechanically superior results for LTO in comparison to the various repair techniques for ST. In another study, Giuseffi and colleagues²⁰ showed no difference in LTO vs ST during biomechanical testing. In response to the increased concern regarding subscapularis integrity, Caplan and colleagues²¹ reported on 45 arthroplasties in 43 patients with improved postoperative testing with intact subscapularis testing in 90% to 100% of patients. A level 1 randomized control trial conducted by Lapner and colleagues²² did not demonstrate any clear clinical advantage of LTO vs ST. Controversy still exists regarding which is the preferred technique for TSA.

Sanchez-Sotelo and colleagues⁴ evaluated uncemented humeral components in 72 patients who underwent TSA. They found a humeral component was at risk for loosening if a radiolucent line ≥2 mm was present in at least 3 radiographic zones. They also evaluated tilt or subsidence by measurement and whether the components were observed to have changed. Their measured values correlated with their observed values. That study provided a benchmark for evaluation of loosening and subsidence used during this study.⁴ Although radiographic follow-up is limited in this study, we feel that any potential subsidence secondary to use of the LTO technique would be radiographically apparent at 1 year. There were 16 patients without adequate radiographic follow-up included in the study. However, we feel that this was not a large concern, because the study was adequately powered with the patients available to determine a difference based on subsidence.

CONCLUSION

We found no difference in subsidence, lucent lines >2 mm, posterior subluxation, and the Constant and DASH functional outcome scores when we compared TSA performed by a LTO with an ST technique with proximal collar press-fit humeral stem. These data cannot be extrapolated to metaphyseal fit stems, which may exhibit different settling characteristics in the setting of the LTO technique.

This paper will be judged for the Resident Writer’s Award.

ABSTRACT

Lesser tuberosity osteotomy (LTO) and subscapularis tenotomy (ST) are used for takedown of the subscapularis during shoulder arthroplasty. LTO offers the theoretical but unproven benefit of improved healing and function of the subscapularis. However, humeral stem subsidence and loosening may be greater when osteotomy is performed, which may compromise functional outcomes. Our hypothesis is that no difference in proximal collar press-fit humeral stem subsidence or loosening exists, with no impairment of functional outcomes using the LTO technique.

During the surgical approach for total shoulder arthroplasty (TSA), the subscapularis is taken down for adequate exposure to the glenohumeral joint. Various methods are available for taking down the subscapularis, including lesser tuberosity osteotomy (LTO) and a subscapularis tenotomy (ST). LTO offers the theoretical but unproven benefit of improved healing and function of the subscapularis secondary to bone-to-bone healing. One concern, however, is that humeral stem subsidence may be greater when an osteotomy is performed owing to compromise of metaphyseal cortical bone, which may compromise functional outcomes. The humeral stem design may also influence subsidence when metaphyseal bone proximally is compromised. This is a concern in both metaphyseal and diaphyseal fitting stems. Metaphyseal collars on diaphyseal fitting stems rely on adequate bone stock in the metaphysis to provide the additional support needed. Also, posterior subluxation remains a challenge in shoulder arthroplasty. The integrity of the subscapularis is important in prevention of posterior subluxation.¹ To our knowledge, no study to date has directly compared differences in humeral stem subsidence, loosening, or posterior subluxation between LTO and ST techniques with any humeral stem design. Our hypothesis is that no difference in proximal collar press-fit humeral stem subsidence or loosening exists, with no impairment of functional outcomes using the LTO technique. We also hypothesize that no difference in posterior subluxation exists between LTO and ST techniques.

MATERIALS AND METHODS

INCLUSION CRITERIA

Consecutive patients with a minimum of 12 months of radiographic follow-up were selected from 2007 to 2010 after TSA was performed by 1 of the senior authors (Dr. Miller and Dr. Voloshin). Study patients underwent primary TSA for primary osteoarthritis or rheumatoid arthritis.

EXCLUSION CRITERIA

Patients were excluded if they underwent TSA for posttraumatic glenohumeral arthritis, hemiarthroplasty, or osteonecrosis. Patients were also excluded if a rotator cuff tear was discovered intraoperatively or if they had a history of a rotator cuff repair. Additional exclusion criteria included postoperative trauma to the operative shoulder, postoperative infection, extensive documentation of chronic pain, and underlying neurologic disorder (eg, Parkinson disease, dystonia). Patients with a history of diabetes mellitus were not excluded.

SURGICAL TECHNIQUE

All patients underwent TSA via a deltopectoral approach in a modified beach chair position. Biceps tendons were tenodesed at the level of the pectoralis major. All patients received the same proximal collar press-fit implant (Bigliani-Flatow; Zimmer Biomet). These stems provide rotational stability in the metaphyseal segment via fins, vertical stability with the proximal collar, and distal fixation via an interference fit. All parts of the procedure were performed in similar fashion with the exception of ST vs LTO (Figures 1A-1D). 

Continue to: LTO was performed as the primary...

LESSER TUBEROSITY OSTEOTOMY

LTO was performed as the primary or preferred technique of 1 surgeon. After completion of the biceps tenodesis, the lesser tuberosity is reflected off with the subscapularis intact using an osteotome. After placement of the press-fit humeral stem, the LTO is repaired using No. 5 Ethibond Excel sutures (Ethicon) passed through previously created bone tunnels in the greater tuberosity. These sutures are tied over metal buttons over the lateral cortex of the greater tuberosity. Last, the lateral corner of the rotator interval is repaired using a single No. 2 FiberWire (Arthrex).²

SUBSCAPULARIS TENOTOMY

ST is the preferred surgical technique of the second surgeon. After a biceps tenodesis, the subscapularis tendon is released from the lesser tuberosity at the margin of the bicipital groove. Through careful dissection, a single flap including the underlying capsule is created and reflected medially to the level of the coracoid. After placement of the press-fit humeral stem and humeral head, the subscapularis is repaired back in place through previous bone tunnels and with a No. 5 Ethibond Excel suture under the appropriate tension. Then, the lateral corner of the rotator interval is closed using a single No. 2 Ethibond Excel suture in a figure-of-eight fashion.²

RADIOGRAPHIC ANALYSIS

The primary variables analyzed were subsidence and loosening. Additional variables, including humeral-acromial distance (HAD) and subluxation index, were also analyzed to assess for any additional impact caused by subsidence or loosening.³ All radiographic measurements were taken from the Grashey (true anteroposterior) view, except subluxation index, which was calculated using the axillary view. All radiographic measurements were completed by 3 independent reviewers. All radiographs were completed in a consistent manner according to postoperative protocols.

HAD was measured preoperatively, immediately postoperatively, and at final follow-up at a minimum of 1 year. The HAD was measured from the lowest point on the acromion to the humerus using a perpendicular line (Figure 2).

Subsidence of the prosthesis was calculated by determining the difference between immediate postoperative heights of the prosthesis in comparison to the value of the final follow-up films. To calculate the height, 2 lines were drawn, 1 line was drawn perpendicular to the top of the prosthetic head and 1 perpendicular to the top of the greater tuberosity (Figure 3). 

Continue to: Posterior subluxation is indicated...

The humeral stems were evaluated for loosening by assessing for lucency on final radiographic follow-up films. These were evaluated in a zonal fashion as demonstrated by Sanchez-Sotelo and colleagues⁴ and in Figure 5. 

FUNCTIONAL OUTCOME EVALUATION

Before clinical evaluation, each study patient completed the Western Ontario Osteoarthritis of the Shoulder (WOOS) index; the Disabilities of the Hand, Arm and Shoulder (DASH) questionnaire, and the pain and function sections of the Constant score. The functional outcomes scores were captured postoperatively from October to November 2011. The WOOS is a validated outcome measure specific to osteoarthritis of the shoulder and has been used in prior studies evaluating outcomes of TSA.^5-7 Previous studies have determined that the minimal clinically important difference for the WOOS score is 15 on a normalized 0 to 100 scale (100 being the best). The DASH score is a validated outcome measure for disorders of the upper extremity but is not specific to osteoarthritis of the shoulder.⁸ The Constant score is a validated outcome measure for a number of shoulder disorders, including TSA.^9,10

STATISTICAL ANALYSIS

Statistical analyses were completed by a trained biostatistician. A power analysis was calculated using the noninferiority test to determine if adequate data had been obtained for this study. This was calculated by using previously accepted data demonstrating a statistically significant difference for subsidence and HAD. The data from these studies were used to make assumptions regarding accepted standard deviations and noninferiority margins, as calculated from the mean values of the 2 groups analyzed in each respective study.^4,11 This analysis demonstrated power of 0.97 and 0.85 for the subsidence and HAD, respectively, given the current sample sizes. Intraclass coefficients were calculated to evaluate the measurements obtained during the radiographic analysis to determine the interrater agreement. Two samples’ t tests were calculated for the variables analyzed, along with P values and means.

RESULTS

DEMOGRAPHICS

A total of 51 consecutive patients were retrospectively selected for analysis. Of these, 16 patients were excluded from the study because they had <9 months of radiographic follow-up and were unavailable for further follow-up evaluation. Of the remaining 35 patients available for analysis, 4 patients had bilateral TSA, providing 39 shoulders for evaluation. Demographic characteristics of the study cohort are reported in Table 1.

  Fifteen patients underwent LTO, and 24 underwent ST. One patient underwent a tenotomy of the right shoulder and LTO of the left shoulder. Three LTOs were performed by the surgeon who primarily performed ST, owing to potential benefits of LTO. He eventually returned to his preferred technique of ST because of surgeon preference. Three ST procedures were completed by the surgeon who typically performed LTO at the start of the series prior to establishing LTO as his preferred technique. There was no significant difference between the study populations in terms of age, follow-up, male-to-female ratio, hand dominance, and primary diagnosis of osteoarthritis vs rheumatoid arthritis.

Continue to: There was no significant difference...

RADIOGRAPHIC DATA

There was no significant difference in preoperative HAD between the LTO and ST groups (9.5 ± 2.4 mm vs 10.9 ± 2.7 mm, P = .11). The immediate postoperative HAD was statistically significant between the LTO and ST groups (11.9 ± 3.7 mm vs 15.9 ± 4.5 mm, P = .005). There was as statistically significant difference noted in the final follow-up films between the LTO and ST groups (11.8 ± 3.2 mm vs 14.5 ± 3.9 mm, P = .025) (Table 2). 

Abbreviations: LTO, lesser tuberosity osteotomy; ST, subscapularis tenotomy.

There were no statistically significant differences found in subsidence between LTO and ST groups at final follow-up (2.8 mm ± 3.1 mm vs 2.5 mm ± 3.1 mm, P = .72) (Table 2). No statistically significant difference was noted in the subluxation index between the LTO and ST groups (0.55% ± .06% vs 0.54% ± 0.07%, P = .45), but there was a statistically significant difference noted postoperatively between the LTO and ST groups (0.55% ± 0.09% vs .48% ± 0.05%, P = .015) (Table 2).

Two stems were noted to have lucent lines >2 mm, both within the ST cohort. Each had 1 stem zone >2 mm, 1 in zone 7, and 1 in zone 4. No statistically significant difference was identified between the LTO and ST groups (0/15 vs 2/24, P = .51) (Table 2).

FUNCTIONAL OUTCOMES

Study patients were evaluated using functional outcome scores, including the Constant, WOOS, and DASH scores (Table 3). 

Abbreviations: DASH, disabilities of the arm, shoulder and hand; WOOS, Western Ontario Osteoarthritis of the Shoulder.

No statistically significant differences were noted in the DASH scores (8.4 ± 6.6 vs 13.8 ± 4.9, P = .13) or Constant scores (83.3 ± 9.1 vs 81.8 ± 10.1, P = .64) between the LTO and ST cohorts. There was a statistically significant difference between the WOOS scores (93.3 ± 5.3 vs 81.5 ± 20.8, P = .013). Because separate radiographic reviews were done by 3 independent personnel at 3 different times, it was important to ensure agreement among the reviewers. This was compared using the intraclass correlation coefficients. In the statistical analysis completed, the intraclass coefficients showed the 3 reviewers agreed with each other throughout the radiographic analysis (Table 4).

Abbreviations: CI, confidence interval; HAD, humeral acromial distance; ICC, intraclass correlation coefficient; SI, subluxation index.

DISCUSSION

At final follow-up, we identified no statistically significant difference between the LTO and ST patients in subsidence, lucent lines >2 mm, or functional outcomes (Constant and DASH scores) in patients who underwent TSA with the same proximal collar press-fit humeral stem. In regard to the functional outcome scores, although the WOOS score was statistically significant (P = .013) between the LTO and ST cohorts, we do not feel that this is clinically relevant because it does not reach the minimal clinically important difference threshold of 15 points.⁸

A statistically significant difference was noted in postoperative subluxation index but was not clinically relevant, because the values between the LTO and ST groups (0.55 vs 0.48) still showed a centered humeral head. Gerber and colleagues³ discussed using a value of 0.65 as a measure of posterior humeral head subluxation, whereas Walch and colleagues¹² defined posterior humeral head subluxation as a value >0.55. On the basis of these numbers, the values obtained in this study demonstrated that the postoperative values were still centered on the glenoid, and therefore were not clinically significant.^3,12

Continue to: In regard to HAD, there...

Studies have shown a concern regarding the integrity of the subscapularis after tenotomy or peel used in TSA with abnormal subscapularis function.^14,15 Miller and colleagues¹⁵ reported 41 patients, nearly two-thirds, of whom described subscapularis dysfunction. Those authors’ response to the poor clinical outcomes was to remove a fleck of bone with the tendon to achieve “bone-to-bone” healing.¹⁴ Gerber and colleagues¹⁶ reported on a series of patients using LTO and repair in TSA with 75% and 89% intact subscapularis function on clinical testing.¹⁶ Studies by Qureshi and colleagues¹⁷ and Scalise and colleagues¹⁸ showed similar results after LTO. Biomechanical studies have shown mixed results. Ponce and colleagues¹⁹ showed biomechanically superior results for LTO in comparison to the various repair techniques for ST. In another study, Giuseffi and colleagues²⁰ showed no difference in LTO vs ST during biomechanical testing. In response to the increased concern regarding subscapularis integrity, Caplan and colleagues²¹ reported on 45 arthroplasties in 43 patients with improved postoperative testing with intact subscapularis testing in 90% to 100% of patients. A level 1 randomized control trial conducted by Lapner and colleagues²² did not demonstrate any clear clinical advantage of LTO vs ST. Controversy still exists regarding which is the preferred technique for TSA.

Sanchez-Sotelo and colleagues⁴ evaluated uncemented humeral components in 72 patients who underwent TSA. They found a humeral component was at risk for loosening if a radiolucent line ≥2 mm was present in at least 3 radiographic zones. They also evaluated tilt or subsidence by measurement and whether the components were observed to have changed. Their measured values correlated with their observed values. That study provided a benchmark for evaluation of loosening and subsidence used during this study.⁴ Although radiographic follow-up is limited in this study, we feel that any potential subsidence secondary to use of the LTO technique would be radiographically apparent at 1 year. There were 16 patients without adequate radiographic follow-up included in the study. However, we feel that this was not a large concern, because the study was adequately powered with the patients available to determine a difference based on subsidence.

CONCLUSION

We found no difference in subsidence, lucent lines >2 mm, posterior subluxation, and the Constant and DASH functional outcome scores when we compared TSA performed by a LTO with an ST technique with proximal collar press-fit humeral stem. These data cannot be extrapolated to metaphyseal fit stems, which may exhibit different settling characteristics in the setting of the LTO technique.

This paper will be judged for the Resident Writer’s Award.

ABSTRACT

The purpose of this study is to determine the effectiveness of tranexamic acid (TXA) alone and in conjunction with a bipolar sealer in reducing postoperative transfusions during direct anterior (DA) total hip arthroplasty (THA).

In this retrospective review, we analyzed 173 consecutive patients who underwent primary unilateral DA THA performed by 2 surgeons during a 1-year period. Subjects were divided into 3 groups based on TXA use: 63 patients received TXA alone (TXA group), 49 patients received TXA in addition to a bipolar sealer (TXA + bipolar sealer group), and 61 patients received neither TXA nor a bipolar sealer (control group). Primary end points were the transfusion rate and estimated blood loss. Secondary end points were length of stay, postoperative drop in hemoglobin, and postoperative drain output.

Two patients in the TXA group and 10 patients in the control group were transfused (P = .02). In the TXA + bipolar sealer group, 1 patient was transfused (P = .02). No significant difference in the rate of transfusion was found between the TXA group and the TXA + bipolar sealer group (P = .99). Estimated blood loss was 310.3 mL ± 182.5 mL in the TXA group (P = .004), 292.9 mL ± 130.8 mL in the TXA + bipolar sealer group (P = .003), and 404.9 mL ± 201.2 mL in the control group. 

The use of TXA, with and without the concomitant use of a bipolar sealer, decreases intraoperative blood loss and postoperative transfusion requirements. The addition of a bipolar sealer, however, does not appear to provide any additional decrease in blood loss.

Historically, patients undergoing total hip arthroplasty (THA) have significant blood loss and required blood transfusions.^1-3 Blood transfusions increase not only the risk of complications but also the cost of the procedure.^4-9 Although less invasive techniques in hip surgery may decrease blood loss,^10-12 intraoperative blood loss remains a concern. Optimization of anemia and blood conservation techniques include preoperative autologous blood donation, perioperative hemodilution, meticulous surgical hemostasis, and the use of antifibrinolytic agents.^4,5,7,13,14 Antifibrinolytics are inexpensive and have been shown to reduce blood loss during THA and total knee arthroplasty (TKA).^7,15-17

Continue to: Tranexamic acid (TXA), a synthetic analog...

Although many studies have analyzed the use of TXA and a bipolar sealer with the posterior and lateral approaches to hip arthroplasty, there is a paucity of research analyzing its use in the DA approach. This study retrospectively reviews the effectiveness of TXA alone and in conjunction with a bipolar sealer in reducing allogeneic blood transfusions in DA THA.

METHODS

This is a retrospective, comparative study evaluating the efficacy of TXA with and without a bipolar sealer in unilateral DA THA. The study included 173 patients who underwent standard DA THA performed by 2 surgeons in the period April 2013 to April 2014. Patient demographic information is summarized in Table 1.

Table 1. Demographic Data

^aResult values are expressed as mean ± standard deviation (range). ^bResult values are expressed as number of cases (percentage of column header population).

Abbreviations: BMI, body mass index; TXA, tranexamic acid.

Three cohorts were created based on intraoperative blood loss management practices at the surgeon’s discretion. The first group included 63 patients who underwent DA THA with TXA but not a bipolar sealer. The second group included 49 patients who underwent DA THA with TXA and a bipolar sealer. The third (control) group included 61 patients who underwent DA THA without TXA or a bipolar sealer. Data for the control group were collected prospectively as a part of a randomized trial, which demonstrated a reduction in transfusion requirements and blood loss with the use of a bipolar sealer in DA THA.²⁸ All patients received a surgical hemovac suction drain, which was removed at 24 hours after surgery. All patients received 40 mg of enoxaparin daily for 2 weeks for venous thromboembolism prophylaxis starting the day after surgery.

All patients in the first 2 groups received 2 g of TXA administered intravenously in 2 doses: the first dose was given preoperatively, and the second dose was given immediately postoperatively in the recovery room. The bipolar sealer was utilized as needed perioperatively according to the manufacturer’s instructions to address specific bleeding targets. The common sites and steps of a DA THA, in which bleeding typically occurs, are:

• The medial femoral circumflex artery during the approach to the capsule;
• The anterior hip capsule vessels prior to capsulotomy;
• The deep branch of the medial femoral circumflex artery and the nutrient vessels to the lesser trochanter encountered while exposing the medial neck and releasing the medial capsule;
• The posterior-superior retinacular arteries encountered after femoral neck osteotomy and removal of the femoral head along the posterior capsule; and
• The branch of the obturator artery encountered during exposure of the acetabular fovea.^29-31

At the time of this study, the transfusion criteria included hemoglobin <8 g/dL in the presence of clinical symptoms.

Continue to: Primary outcome measures...

OUTCOME MEASURES AND DATA ANALYSIS

Primary outcome measures were transfusion requirements and estimated blood loss. Secondary outcome measures were postoperative decrease in hemoglobin, length of stay, and postoperative drain output. Demographic and operative data were compared between groups to ensure that there were no statistically significant differences in blood loss and transfusion requirements. All data were recorded in a password encrypted file and subsequently transferred to the REDCap system (Research Electronic Data Capture, Vanderbilt University).

STATISTICAL ANALYSIS

A priori sample size calculation was performed on the basis of a prior study ²⁸, which evaluated surgical blood loss reduction utilizing a bipolar sealer. This study suggested a sample size of 20 per group to detect the minimal clinically important difference of 1.5 (standard deviation (SD) = 1.5, α = 0.05, β = 0.20). Additionally, a general estimate for detecting a 1-unit change on an ordinal scale of 136 (SD = 1.0, α = 0.05, β = 0.20) resulted in the same number. We conservatively chose to include at least 24 patients in each study arm in the event of greater true variance. The Wilcoxon rank-sum test was used for comparison of continuous data between groups. Differences between means were analyzed using 2-sided t tests. Comparison of categorical data was performed using Pearson’s chi-square or Fisher’s exact probability test as indicated. Ordinal ranking scores were compared using the Mantel-Haenszel test.

RESULTS

There were no statistically significant differences between groups with respect to sex, age, body mass index, or preoperative hemoglobin level (Table 1). Two patients in the TXA group and 10 patients in the control group were transfused (P = .02). In the TXA + bipolar sealer group, 1 patient was transfused (P = .02). A comparison of the transfusion rate between the TXA group and the TXA + bipolar sealer group yielded no significant difference (P = .99). The estimated blood loss was 310.3 mL ± 182.5 mL in the TXA group (P = .004), 292.9 mL ± 130.8 mL in the TXA + bipolar sealer group (P = .003), and 404.9 mL ± 201.2 mL in the control group (P = .71) (Table 2).

Table 2. Patient-Related Outcomes

^aResult values are expressed as mean ± standard deviation (range). ^bResult values are expressed as number of cases (percentage of column header population).

Abbreviation: TXA, tranexamic acid.

The total drain output was 326.3 mL ± 197.5 mL in the TXA group (P < .001 for comparison with the control group), 309.8 mL ± 196.3 mL in the TXA + bipolar sealer group (P < .001 for comparison with the control group), and 473.6 mL ± 199.7 mL in the control group (P = .58). The decrease in hemoglobin was 3.5 g/dL ± 0.8 g/dL in the TXA group (P < .001), 3.5 g/dL ± 1.1 g/dL in the TXA + bipolar sealer group (P < .001), and 4.3 g/dL ± 1.2 g/dL in the control group (Table 2). The length of stay was 2.2 ± 0.6 days for the TXA group (P = .004) and 2.2 ± 0.9 days (P = .03) for the TXA + bipolar sealer group, and 2.6 ± 0.8 days in the control group (P = .78) (Table 2).

DISCUSSION

This study shows that the use of TXA alone provides a significant decrease in transfusion rates and estimated blood loss, a benefit which was not further increased with the addition of a bipolar sealer (Table 2). Many studies have demonstrated that TXA reduces blood loss and transfusion rates in patients undergoing THA and TKA.²⁹ However, TXA’s acceptance as a more readily used hemostatic medication has been hindered by the theoretically increased risk of thromboembolism in susceptible, high-risk patients.^32-35 In a 2012 meta-analysis conducted by Yang and colleagues,³⁶ the use of TXA led to significantly less blood loss per patient and fewer transfusions without leading to an increased risk of thromboembolic events.

Continue to: Similarly, the bipolar sealer...

Although the results of our research are in line with those of previous publications, it is important to address 3 limitations within this study. First, only the control group in this study was enrolled prospectively; the remaining groups were reviewed retrospectively. Second, our adoption of TXA was recent; therefore, a confounding factor is that our surgeons had more experience in the anterior approach when using TXA. Third, the established transfusion threshold of <8 g/dl for this study led to more liberal use of transfusions. Since the conclusion of this study, we have adopted stricter transfusion criteria (hemoglobin <7.0 g/dL with clinical symptoms) which has led to even lower transfusion requirements.

CONCLUSION

In the reviewed patient population, TXA decreased blood loss and transfusion requirements following DA THA. However, the addition of a bipolar sealer did not provide an advantage. The results of this study do not support the routine use of a bipolar sealer in DA THA.