Hip

Genotype-guided warfarin dosing reduced anticoagulation-related adverse events by almost 4% compared with a clinically based warfarin-dosing regimen in a randomized trial of 1,650 elderly patients undergoing hip or knee arthroplasty.

The difference in the composite endpoint (major bleeding within 30 days, international normalized ratio [INR] of 4 or greater within 30 days, venous thromboembolism within 60 days, or death within 30 days) in the Genetic Informatics Trial of Warfarin to Prevent Deep Vein Thrombosis (GIFT) trial was mainly driven by a significant difference in episodes of elevated INR, reported Brian F. Gage, MD, and his colleagues (JAMA 2017;318[12]:1115-1124. doi: 10.1001/jama.2017.11469).

A total of 1,597 patients completed the trial. Of 808 patients in the genotype-guided group, 10.8% met one of the endpoints. Of 789 in the clinically guided warfarin dosing group, 14.7% met at least 1 of the endpoints. There were no deaths in the study.

“Widespread use of genotype-guided dosing will depend on reimbursement, regulations, and logistics. Although several commercial platforms for warfarin-related genes have been approved by the Food and Drug Administration and the European Medicines Agency, routine genotyping is not yet recommended,” wrote Dr. Gage of Washington University, St. Louis, and his coauthors.

The Centers for Medicare and Medicaid Services used its Coverage with Evidence Development program to fund genotyping in this trial and will review the results to determine future coverage, the researchers added.

In GIFT, patients were randomized to an 11-day regimen of warfarin guided either by a clinical algorithm or by their individual genotype. The team tested for four polymorphisms known to affect warfarin metabolism: VKORC1-1639G>A, CYP2C9*2, CYP2C9*3, and CYP4F2 V433M. The treatment goal was an INR of 1.8-2. After 11 days, physicians could administer warfarin according to their own judgment.

The absolute difference of 3.9% in the composite endpoint was largely driven by a 2.8% absolute difference in the rate of an INR of 4 or greater. The rate difference between the two groups was 0.8% for major bleeding, and 0.7% for VTE.

About 41% of the cohort was considered to be at high risk of bleeding complications, and this group accrued the highest benefit from genotype-based dosing. Among them, the composite endpoint was 11.5% compared with 15.2% in the clinical algorithm group – an absolute difference of 3.76%.

The benefit was consistent among black patients, and those with CYP2C9.

By day 90, one VTE had occurred in each group. An intracranial hemorrhage occurred in one patient in the clinically guided group, 2 months after stopping warfarin.

The clinical benefit of genotype-based dosing influenced 90-day outcomes as well, with the composite endpoint occurring in 11% of the genotype group and 15% of the clinically guided group (absolute difference 3.9%).

Among the 1,588 patients who had their percentage of time in the therapeutic range (PTTR) calculated, genotyping improved PTTR time by 3.4% overall. The effect was especially strong from days 4 to 14, when it improved PTTR by 5.7% relative to clinical guidance.

Three other studies have examined the effect of a genotype-based warfarin dosing regimen, Dr. Gage and his coauthors noted: Two found no benefit, and a third found that such guidance improved INR control. GIFT has several advantages over those trials, which the authors said lend credence to its results.

“Compared with previous studies, this trial was larger, used genotype-guided dosing for a longer duration, and incorporated more genes into the dosing algorithm …The longer period of genotype-guided dosing likely prevented cases of supratherapeutic INR that were common in these trials,” they wrote.

Dr. Gage reported no financial disclosures, but several coauthors reported ties with pharmaceutical and imaging companies.

msullivan@frontlinemedcom.com

Genotype-guided warfarin dosing reduced anticoagulation-related adverse events by almost 4% compared with a clinically based warfarin-dosing regimen in a randomized trial of 1,650 elderly patients undergoing hip or knee arthroplasty.

The difference in the composite endpoint (major bleeding within 30 days, international normalized ratio [INR] of 4 or greater within 30 days, venous thromboembolism within 60 days, or death within 30 days) in the Genetic Informatics Trial of Warfarin to Prevent Deep Vein Thrombosis (GIFT) trial was mainly driven by a significant difference in episodes of elevated INR, reported Brian F. Gage, MD, and his colleagues (JAMA 2017;318[12]:1115-1124. doi: 10.1001/jama.2017.11469).

A total of 1,597 patients completed the trial. Of 808 patients in the genotype-guided group, 10.8% met one of the endpoints. Of 789 in the clinically guided warfarin dosing group, 14.7% met at least 1 of the endpoints. There were no deaths in the study.

“Widespread use of genotype-guided dosing will depend on reimbursement, regulations, and logistics. Although several commercial platforms for warfarin-related genes have been approved by the Food and Drug Administration and the European Medicines Agency, routine genotyping is not yet recommended,” wrote Dr. Gage of Washington University, St. Louis, and his coauthors.

The Centers for Medicare and Medicaid Services used its Coverage with Evidence Development program to fund genotyping in this trial and will review the results to determine future coverage, the researchers added.

In GIFT, patients were randomized to an 11-day regimen of warfarin guided either by a clinical algorithm or by their individual genotype. The team tested for four polymorphisms known to affect warfarin metabolism: VKORC1-1639G>A, CYP2C9*2, CYP2C9*3, and CYP4F2 V433M. The treatment goal was an INR of 1.8-2. After 11 days, physicians could administer warfarin according to their own judgment.

The absolute difference of 3.9% in the composite endpoint was largely driven by a 2.8% absolute difference in the rate of an INR of 4 or greater. The rate difference between the two groups was 0.8% for major bleeding, and 0.7% for VTE.

About 41% of the cohort was considered to be at high risk of bleeding complications, and this group accrued the highest benefit from genotype-based dosing. Among them, the composite endpoint was 11.5% compared with 15.2% in the clinical algorithm group – an absolute difference of 3.76%.

The benefit was consistent among black patients, and those with CYP2C9.

By day 90, one VTE had occurred in each group. An intracranial hemorrhage occurred in one patient in the clinically guided group, 2 months after stopping warfarin.

The clinical benefit of genotype-based dosing influenced 90-day outcomes as well, with the composite endpoint occurring in 11% of the genotype group and 15% of the clinically guided group (absolute difference 3.9%).

Among the 1,588 patients who had their percentage of time in the therapeutic range (PTTR) calculated, genotyping improved PTTR time by 3.4% overall. The effect was especially strong from days 4 to 14, when it improved PTTR by 5.7% relative to clinical guidance.

Three other studies have examined the effect of a genotype-based warfarin dosing regimen, Dr. Gage and his coauthors noted: Two found no benefit, and a third found that such guidance improved INR control. GIFT has several advantages over those trials, which the authors said lend credence to its results.

“Compared with previous studies, this trial was larger, used genotype-guided dosing for a longer duration, and incorporated more genes into the dosing algorithm …The longer period of genotype-guided dosing likely prevented cases of supratherapeutic INR that were common in these trials,” they wrote.

Dr. Gage reported no financial disclosures, but several coauthors reported ties with pharmaceutical and imaging companies.

msullivan@frontlinemedcom.com

Genotype-guided warfarin dosing reduced anticoagulation-related adverse events by almost 4% compared with a clinically based warfarin-dosing regimen in a randomized trial of 1,650 elderly patients undergoing hip or knee arthroplasty.

The difference in the composite endpoint (major bleeding within 30 days, international normalized ratio [INR] of 4 or greater within 30 days, venous thromboembolism within 60 days, or death within 30 days) in the Genetic Informatics Trial of Warfarin to Prevent Deep Vein Thrombosis (GIFT) trial was mainly driven by a significant difference in episodes of elevated INR, reported Brian F. Gage, MD, and his colleagues (JAMA 2017;318[12]:1115-1124. doi: 10.1001/jama.2017.11469).

A total of 1,597 patients completed the trial. Of 808 patients in the genotype-guided group, 10.8% met one of the endpoints. Of 789 in the clinically guided warfarin dosing group, 14.7% met at least 1 of the endpoints. There were no deaths in the study.

“Widespread use of genotype-guided dosing will depend on reimbursement, regulations, and logistics. Although several commercial platforms for warfarin-related genes have been approved by the Food and Drug Administration and the European Medicines Agency, routine genotyping is not yet recommended,” wrote Dr. Gage of Washington University, St. Louis, and his coauthors.

The Centers for Medicare and Medicaid Services used its Coverage with Evidence Development program to fund genotyping in this trial and will review the results to determine future coverage, the researchers added.

In GIFT, patients were randomized to an 11-day regimen of warfarin guided either by a clinical algorithm or by their individual genotype. The team tested for four polymorphisms known to affect warfarin metabolism: VKORC1-1639G>A, CYP2C9*2, CYP2C9*3, and CYP4F2 V433M. The treatment goal was an INR of 1.8-2. After 11 days, physicians could administer warfarin according to their own judgment.

The absolute difference of 3.9% in the composite endpoint was largely driven by a 2.8% absolute difference in the rate of an INR of 4 or greater. The rate difference between the two groups was 0.8% for major bleeding, and 0.7% for VTE.

About 41% of the cohort was considered to be at high risk of bleeding complications, and this group accrued the highest benefit from genotype-based dosing. Among them, the composite endpoint was 11.5% compared with 15.2% in the clinical algorithm group – an absolute difference of 3.76%.

The benefit was consistent among black patients, and those with CYP2C9.

By day 90, one VTE had occurred in each group. An intracranial hemorrhage occurred in one patient in the clinically guided group, 2 months after stopping warfarin.

The clinical benefit of genotype-based dosing influenced 90-day outcomes as well, with the composite endpoint occurring in 11% of the genotype group and 15% of the clinically guided group (absolute difference 3.9%).

Among the 1,588 patients who had their percentage of time in the therapeutic range (PTTR) calculated, genotyping improved PTTR time by 3.4% overall. The effect was especially strong from days 4 to 14, when it improved PTTR by 5.7% relative to clinical guidance.

Three other studies have examined the effect of a genotype-based warfarin dosing regimen, Dr. Gage and his coauthors noted: Two found no benefit, and a third found that such guidance improved INR control. GIFT has several advantages over those trials, which the authors said lend credence to its results.

“Compared with previous studies, this trial was larger, used genotype-guided dosing for a longer duration, and incorporated more genes into the dosing algorithm …The longer period of genotype-guided dosing likely prevented cases of supratherapeutic INR that were common in these trials,” they wrote.

Dr. Gage reported no financial disclosures, but several coauthors reported ties with pharmaceutical and imaging companies.

msullivan@frontlinemedcom.com

Take-Home Points

• IV-TXA significantly reduces intraoperative blood loss following TJA.
• Early mobilization correlates with reduced incidence of postoperative complications.
• IV-TXA minimizes postoperative anemia, facilitating improved early ambulation following TJA.
• IV-TXA significantly reduces the need for postoperative transfusions.
• IV-TXA is safe to use with no adverse events noted.

By the year 2020, use of primary total knee arthroplasty (TKA) in the United States will increase an estimated 110%, to 1.375 million procedures annually, and use of primary total hip arthroplasty (THA) will increase an estimated 75%, to more than 500,000 procedures.¹ Minimizing perioperative blood loss and improving early postoperative ambulation both correlate with reduced postoperative morbidity, allowing patients to return to their daily lives expeditiously. 

Tranexamic acid (TXA), a fibrinolytic inhibitor, competitively blocks lysine receptor binding sites of plasminogen, sustaining and stabilizing the fibrin architecture.² TXA must be present to occupy binding sites before plasminogen binds to fibrin, validating the need for preoperative administration so the drug is available early in the fibrinolytic cascade.³ Intravenous (IV) TXA diffuses rapidly into joint fluid and the synovial membrane.⁴ Drug concentration and elimination half-life in joint fluid are equivalent to those in serum. Elimination of TXA occurs by glomerular filtration, with about 30% of a 10-mg/kg dose removed in 1 hour, 55% over the first 3 hours, and 90% within 24 hours of IV administration.⁵

The efficacy of IV-TXA in minimizing total joint arthroplasty (TJA) perioperative blood loss has been proved in small studies and meta-analyses.^6-9 TXA-induced blood conservation decreases or eliminates the need for postoperative transfusion, which can impede valuable, early ambulation.10 In addition, the positive clinical safety profile of TXA supports routine use of TXA in TJA.^6,11-15

The benefits of early ambulation after TJA are well established. Getting patients to walk on the day of surgery is a key part of effective and rapid postoperative rehabilitation. Early mobilization correlates with reduced incidence of venous thrombosis and postoperative complications.¹⁶ In contrast to bed rest, sitting and standing promotes oxygen saturation, which improves tissue healing and minimizes adverse pulmonary events. Oxygen saturation also preserves muscle strength and blood flow, reducing the risk of venous thromboembolism and ulcers. Muscle strength must be maintained so normal gait can be regained.¹⁷ Compared with rehabilitation initiated 48 to 72 hours after TKA, rehabilitation initiated within 24 hours reduced the number of sessions needed to achieve independence and normal gait; in addition, early mobilization improved patient reports of pain after surgery.¹⁸ An evaluation of Denmark registry data revealed that mobilization to walking and use of crutches or canes was achieved earlier when ambulation was initiated on day of surgery.¹⁹ Finally, mobilization on day of surgery and during the immediate postoperative period improved long-term quality of life after TJA.²⁰

We conducted a retrospective cohort study to determine if use of IV-TXA improves early ambulation and reduces blood loss after TKA and anterior and posterior THA. We hypothesized that IV-TXA use would reduce postoperative anemia and improve early ambulation and outcomes without producing adverse events during the immediate postoperative period. TXA reduces bleeding, and reduced incidence of hemarthrosis, wound swelling, and anemia could facilitate ambulation, reduce complications, and shorten recovery in patients who undergo TJA.

Patients and Methods

In February 2014, this retrospective cohort study received Institutional Review Board approval to compare the safety and efficacy of IV-TXA (vs no TXA) in patients who underwent TKA, anterior THA, and posterior THA.

In March 2012, multidisciplinary protocols were standardized to ensure a uniform hospital course for patients at our institution. All patients underwent preoperative testing and evaluation by a nurse practitioner and an anesthesiologist. In March 2013, IV-TXA became our standard of care. TXA use was contraindicated in patients with thromboembolic disease or with hypersensitivity to TXA. Patients without a contraindication were given two 10-mg/kg IV-TXA doses, each administered over 15 to 30 minutes; the first dose was administered before incision, and the second was infused at case close and/or at least 60 minutes after the first dose. Most TKA patients received regional (femoral) anesthesia and analgesia, and most THA patients received spinal or epidural anesthesia and analgesia. In a small percentage of cases, IV analgesia was patient-controlled, as determined by the pain service. There were no significant differences in anesthesia/analgesia modality between the 2 study groups—patients who received TXA and those who did not. Patients were then transitioned to oral opioids for pain management, unless otherwise contraindicated, and were ambulated 4 hours after end of surgery, unless medically unstable. Hematology and chemistry laboratory values were monitored daily during admission.

Patients underwent physical therapy (PT) after surgery and until hospital discharge. Physical therapists blinded to patients’ intraoperative use or no use of TXA measured ambulation. After initial evaluation on postoperative day 0 (POD-0), patients were ambulated twice daily. The daily ambulation distance used for the study was the larger of the 2 daily PT distances (occasionally, patients were unable to participate fully in both sessions). Patients received either enoxaparin or rivaroxaban for postoperative thromboprophylaxis (the anticoagulant used was based on surgeon preference). Enoxaparin was subcutaneously administered at 30 mg every 12 hours for TKA, 40 mg once daily for THA, 30 mg once daily for calculated creatinine clearance under 30 mL/min, or 40 mg every 12 hours for body mass index (BMI) 40 or above. With enoxaparin, therapy duration was 14 days. Oral rivaroxaban was administered at 10 mg once daily for 12 days for TKA and 35 days for THA unless contraindicated.

The primary outcome variables were ambulation measured on POD-1 and POD-2 and intraoperative blood loss. In addition, hemoglobin and hematocrit were measured on POD-0, POD-1, and POD-2. Ambulation was defined as number of feet walked during postoperative hospitalization. To calculate intraoperative blood loss, the anesthesiologist subtracted any saline irrigation volume from the total volume in the suction canister. Also noted were postoperative transfusions and any diagnosis of postoperative venous thromboembolism—specifically, deep vein thrombosis (DVT) or pulmonary embolism (PE).

Demographic and clinical characteristics of the TXA and no-TXA groups were compared using either 2-sample t test (for continuous variables) or χ2 test (for categorical variables).

The ambulation outcome was log-transformed to meet standard assumptions of Gaussian residuals and equality of variance. Means and 95% confidence intervals (CIs) were calculated on the log scale and were anti-logged so the results could be presented in their original units. 

A linear mixed model was used to model intraoperative blood loss as a function of group (TXA, no TXA), procedure (TKA, anterior THA, posterior THA), and potential confounders (age, sex, BMI, operative time).

Linear mixed models for repeated measures were used to compare outcomes (hemoglobin, hematocrit) between groups (TXA, no TXA) and procedures (TKA, anterior THA, posterior THA) and to compare changes in outcomes over time. Group, procedure, and operative time interactions were explored. Potential confounders (age, sex, BMI, operative time) were included in the model as well.

A χ2 test was used to compare the groups (TXA, no TXA) on postoperative blood transfusion (yes, no). Given the smaller number of events, a more complex model accounting for clustered data and potential confounders was not used. Need for transfusion was clinically assessed case by case. Symptomatic anemia (dyspnea on exertion, headaches, tachycardia) was used as the primary indication for transfusion once hemoglobin fell below 8 g/dL or hematocrit below 24%. Number of patients with a postoperative thrombus formation was minimal. Therefore, this outcome was described with summary statistics and was not formally analyzed.

Results

Of the 477 patients who underwent TJAs (275 TKAs, 98 anterior THAs, 104 posterior THAs; all unilateral), 111 did not receive TXA (June 2012-February 2013), and 366 received TXA (March 2013-January 2014). Other than for the addition of IV-TXA, the same standardized protocols instituted in March 2012 continued throughout the study period. The difference in sample size between the TXA and no-TXA groups was not statistically significant and did not influence the outcome measures.

Ambulation

There was a significant (P = .0066) 3-way interaction of TXA, procedure, and operative time after adjusting for age (P < .0001), sex (P < .0001), BMI (P < .0001), and operative time (P = .8308). Regarding TKA, mean ambulation was higher for the TXA group than for the no-TXA group at POD-1 (8.36 vs 3.40 feet; P < .0001) and POD-2 (25.81 vs 18.75 feet; P = .0054). The same was true for anterior THA at POD-1 (10.86 vs 3.33 feet; P < .0001) and POD-2 (27.24 vs 13.19 feet; P < .0001) and posterior THA at POD-1 (10.64 vs 3.37 feet; P < .0001) and POD-2 (24.68 vs 12.93 feet; P = .0002). See Table 3.

Intraoperative Blood Loss

There was a significant 3-way interaction of TXA, procedure (P < .0053), and operative time (P < .0001) after adjusting for age (P < .6136), sex (P = .1147), and BMI (P = .6180). Regarding TKA, mean intraoperative blood loss was significantly lower for the TXA group than for the no-TXA group (241.58 vs 287.81 mL; P = .0004). The same was true for anterior THA (352.91 vs 533.79 mL; P < .0001). Regarding posterior THA, there was no significant difference between the TXA and no-TXA groups (326.00 vs 350.16 mL; P = .3246). See Table 4. 

Hemoglobin

There was a significant (P = .0008) 3-way interaction of TXA, procedure, and operative time after adjusting for age (P = .0174), sex (P < .0001), BMI (P = .0007), and operative time (P = .0002). Regarding TKA, postoperative hemoglobin levels were higher for the TXA group than for the no-TXA group at POD-0 (12.10 vs 11.68 g/dL; P = .0135), POD-1 (11.62 vs 10.67 g/dL; P < .0001), and POD-2 (11.02 vs 10.11 g/dL; P < .0001). The same was true for anterior THA at POD-1 (11.03 vs 10.19 g/dL; P = .0034) and POD-2 (10.57 vs 9.64 g/dL; P = .0009) and posterior THA at POD-2 (11.04 vs 10.16 g/dL; P = .0003). See Table 5.

Hematocrit

There was a significant (P < .0006) 3-way interaction of TXA, procedure, and operative time after adjusting for age (P = .1597), sex (P < .0001), BMI (P < .0001), and operative time (P = .0003). Regarding TKA, postoperative hematocrit levels were higher for the TXA group than for the no-TXA group at POD-0 (36.52% vs 34.65%; P < .0001), POD-1 (34.62% vs 31.83%; P < .0001), and POD-2 (33.01% vs 30.20%; P < .0001). The same was true for anterior THA at POD-1 (32.82% vs 30.59%; P = .0037) and POD-2 (31.58% vs 28.61%; P = .0004) and posterior THA at POD-2 (32.93% vs 30.17%; P < .0001). See Table 6.

Postoperative Transfusions 

Of the 477 patients, 25 (5.24%) required a postoperative transfusion. Postoperative transfusions were less likely (P < .0001) required in the TXA group (1.64%, 6/366) than in the no-TXA group (17.12%, 19/111). Given the smaller number of events, a more complex model accounting for clustered data and potential confounders was not used, and the different procedures were not evaluated separately.

Deep Vein Thrombosis and Pulmonary Embolism

Of the 477 patients, 2 developed a DVT, and 5 developed a PE. Both DVTs occurred in the TXA group (2/366, 0.55%; 95% CI, 0.07%-1.96%). Of the 5 PEs, 4 occurred in the TXA group (4/366, 1.09%; 95% CI, 0.30%-2.77%), and 1 occurred in the no-TXA group (1/111, 0.90%; 95% CI, 0.02%-4.92%). Given the exceedingly small number of events, no statistical significance was noted between groups.

Discussion

Orthopedic surgeons carefully balance patient expectations, societal needs, and regulatory mandates while providing excellent care and working under payers’ financial restrictions. The Centers for Medicare & Medicaid Services announced that, starting in 2016, TJAs will be reimbursed in total as a single bundled payment, adding to the need to provide optimal care in a fiscally responsible manner.²¹ Standardized protocols implementing multimodal therapies are pivotal in achieving favorable postoperative outcomes.

Our study results showed that IV-TXA use minimized hemoglobin and hematocrit reductions after TKA, anterior THA, and posterior THA. Postoperative anemia correlates with decreased ambulation ability and performance during the early postoperative period. In general, higher postoperative hemoglobin and hematocrit levels result in improved motor performance and shorter recovery.²² In addition, early ambulation is a validated predictor of favorable TJA outcomes. In our study, for TKA, anterior THA, and posterior THA, ambulation on POD-1 and POD-2 was significantly better for patients who received TXA than for patients who did not.

Transfusion rates were markedly lower for our TXA group than for our no-TXA group (1.64% vs 17.12%), confirming the findings of numerous other studies on outcomes of TJA with TXA.^{2,3,6-12,14,15} Transfusions impede physical therapy and affect hospitalization costs.

Although potential thrombosis-related adverse events remain an endpoint in studies involving TXA, we found a comparably low incidence of postoperative venous thrombosis in our TXA and no-TXA groups (1.09% and 0.90%, respectively). In addition, no patient in either group developed a postoperative arterial thrombosis.

This is the largest single-center study of TXA use in TKA, anterior THA, and posterior THA. The effect of TXA use on postoperative ambulation was not previously found with TJA.

This study had its limitations. First, it was not prospective, randomized, or double-blinded. However, the physical therapists who mobilized patients and recorded ambulation data were blinded to the study and its hypothesis and followed a standardized protocol for all patients. In addition, intraoperative blood loss was recorded by an anesthesiologist using a standardized protocol, and patients received TXA per orthopedic protocol and surgeon preference, without selection bias. Another limitation was that ambulation data were captured only for POD-1 and POD-2 (most patients were discharged by POD-3). However, a goal of the study was to capture immediate postoperative data in order to determine the efficacy of intraoperative TXA. Subsequent studies can determine if this early benefit leads to long-term clinical outcome improvements.

In reducing blood loss and transfusion rates, intra-articular TXA is as efficacious as IV-TXA.^23-25 We anticipate that the improved clinical outcomes found with IV-TXA in our study will be similar with intra-articular TXA, but more study is needed to confirm this hypothesis.

Conclusion

This retrospective cohort study found that use of IV-TXA in TJA improved early ambulation and clinical outcomes (reduced anemia, fewer transfusions) in the initial postoperative period, without producing adverse events.

Take-Home Points

• IV-TXA significantly reduces intraoperative blood loss following TJA.
• Early mobilization correlates with reduced incidence of postoperative complications.
• IV-TXA minimizes postoperative anemia, facilitating improved early ambulation following TJA.
• IV-TXA significantly reduces the need for postoperative transfusions.
• IV-TXA is safe to use with no adverse events noted.

By the year 2020, use of primary total knee arthroplasty (TKA) in the United States will increase an estimated 110%, to 1.375 million procedures annually, and use of primary total hip arthroplasty (THA) will increase an estimated 75%, to more than 500,000 procedures.¹ Minimizing perioperative blood loss and improving early postoperative ambulation both correlate with reduced postoperative morbidity, allowing patients to return to their daily lives expeditiously. 

Tranexamic acid (TXA), a fibrinolytic inhibitor, competitively blocks lysine receptor binding sites of plasminogen, sustaining and stabilizing the fibrin architecture.² TXA must be present to occupy binding sites before plasminogen binds to fibrin, validating the need for preoperative administration so the drug is available early in the fibrinolytic cascade.³ Intravenous (IV) TXA diffuses rapidly into joint fluid and the synovial membrane.⁴ Drug concentration and elimination half-life in joint fluid are equivalent to those in serum. Elimination of TXA occurs by glomerular filtration, with about 30% of a 10-mg/kg dose removed in 1 hour, 55% over the first 3 hours, and 90% within 24 hours of IV administration.⁵

The efficacy of IV-TXA in minimizing total joint arthroplasty (TJA) perioperative blood loss has been proved in small studies and meta-analyses.^6-9 TXA-induced blood conservation decreases or eliminates the need for postoperative transfusion, which can impede valuable, early ambulation.10 In addition, the positive clinical safety profile of TXA supports routine use of TXA in TJA.^6,11-15

The benefits of early ambulation after TJA are well established. Getting patients to walk on the day of surgery is a key part of effective and rapid postoperative rehabilitation. Early mobilization correlates with reduced incidence of venous thrombosis and postoperative complications.¹⁶ In contrast to bed rest, sitting and standing promotes oxygen saturation, which improves tissue healing and minimizes adverse pulmonary events. Oxygen saturation also preserves muscle strength and blood flow, reducing the risk of venous thromboembolism and ulcers. Muscle strength must be maintained so normal gait can be regained.¹⁷ Compared with rehabilitation initiated 48 to 72 hours after TKA, rehabilitation initiated within 24 hours reduced the number of sessions needed to achieve independence and normal gait; in addition, early mobilization improved patient reports of pain after surgery.¹⁸ An evaluation of Denmark registry data revealed that mobilization to walking and use of crutches or canes was achieved earlier when ambulation was initiated on day of surgery.¹⁹ Finally, mobilization on day of surgery and during the immediate postoperative period improved long-term quality of life after TJA.²⁰

We conducted a retrospective cohort study to determine if use of IV-TXA improves early ambulation and reduces blood loss after TKA and anterior and posterior THA. We hypothesized that IV-TXA use would reduce postoperative anemia and improve early ambulation and outcomes without producing adverse events during the immediate postoperative period. TXA reduces bleeding, and reduced incidence of hemarthrosis, wound swelling, and anemia could facilitate ambulation, reduce complications, and shorten recovery in patients who undergo TJA.

Patients and Methods

In February 2014, this retrospective cohort study received Institutional Review Board approval to compare the safety and efficacy of IV-TXA (vs no TXA) in patients who underwent TKA, anterior THA, and posterior THA.

In March 2012, multidisciplinary protocols were standardized to ensure a uniform hospital course for patients at our institution. All patients underwent preoperative testing and evaluation by a nurse practitioner and an anesthesiologist. In March 2013, IV-TXA became our standard of care. TXA use was contraindicated in patients with thromboembolic disease or with hypersensitivity to TXA. Patients without a contraindication were given two 10-mg/kg IV-TXA doses, each administered over 15 to 30 minutes; the first dose was administered before incision, and the second was infused at case close and/or at least 60 minutes after the first dose. Most TKA patients received regional (femoral) anesthesia and analgesia, and most THA patients received spinal or epidural anesthesia and analgesia. In a small percentage of cases, IV analgesia was patient-controlled, as determined by the pain service. There were no significant differences in anesthesia/analgesia modality between the 2 study groups—patients who received TXA and those who did not. Patients were then transitioned to oral opioids for pain management, unless otherwise contraindicated, and were ambulated 4 hours after end of surgery, unless medically unstable. Hematology and chemistry laboratory values were monitored daily during admission.

Patients underwent physical therapy (PT) after surgery and until hospital discharge. Physical therapists blinded to patients’ intraoperative use or no use of TXA measured ambulation. After initial evaluation on postoperative day 0 (POD-0), patients were ambulated twice daily. The daily ambulation distance used for the study was the larger of the 2 daily PT distances (occasionally, patients were unable to participate fully in both sessions). Patients received either enoxaparin or rivaroxaban for postoperative thromboprophylaxis (the anticoagulant used was based on surgeon preference). Enoxaparin was subcutaneously administered at 30 mg every 12 hours for TKA, 40 mg once daily for THA, 30 mg once daily for calculated creatinine clearance under 30 mL/min, or 40 mg every 12 hours for body mass index (BMI) 40 or above. With enoxaparin, therapy duration was 14 days. Oral rivaroxaban was administered at 10 mg once daily for 12 days for TKA and 35 days for THA unless contraindicated.

The primary outcome variables were ambulation measured on POD-1 and POD-2 and intraoperative blood loss. In addition, hemoglobin and hematocrit were measured on POD-0, POD-1, and POD-2. Ambulation was defined as number of feet walked during postoperative hospitalization. To calculate intraoperative blood loss, the anesthesiologist subtracted any saline irrigation volume from the total volume in the suction canister. Also noted were postoperative transfusions and any diagnosis of postoperative venous thromboembolism—specifically, deep vein thrombosis (DVT) or pulmonary embolism (PE).

Demographic and clinical characteristics of the TXA and no-TXA groups were compared using either 2-sample t test (for continuous variables) or χ2 test (for categorical variables).

The ambulation outcome was log-transformed to meet standard assumptions of Gaussian residuals and equality of variance. Means and 95% confidence intervals (CIs) were calculated on the log scale and were anti-logged so the results could be presented in their original units. 

A linear mixed model was used to model intraoperative blood loss as a function of group (TXA, no TXA), procedure (TKA, anterior THA, posterior THA), and potential confounders (age, sex, BMI, operative time).

Linear mixed models for repeated measures were used to compare outcomes (hemoglobin, hematocrit) between groups (TXA, no TXA) and procedures (TKA, anterior THA, posterior THA) and to compare changes in outcomes over time. Group, procedure, and operative time interactions were explored. Potential confounders (age, sex, BMI, operative time) were included in the model as well.

A χ2 test was used to compare the groups (TXA, no TXA) on postoperative blood transfusion (yes, no). Given the smaller number of events, a more complex model accounting for clustered data and potential confounders was not used. Need for transfusion was clinically assessed case by case. Symptomatic anemia (dyspnea on exertion, headaches, tachycardia) was used as the primary indication for transfusion once hemoglobin fell below 8 g/dL or hematocrit below 24%. Number of patients with a postoperative thrombus formation was minimal. Therefore, this outcome was described with summary statistics and was not formally analyzed.

Results

Of the 477 patients who underwent TJAs (275 TKAs, 98 anterior THAs, 104 posterior THAs; all unilateral), 111 did not receive TXA (June 2012-February 2013), and 366 received TXA (March 2013-January 2014). Other than for the addition of IV-TXA, the same standardized protocols instituted in March 2012 continued throughout the study period. The difference in sample size between the TXA and no-TXA groups was not statistically significant and did not influence the outcome measures.

Ambulation

There was a significant (P = .0066) 3-way interaction of TXA, procedure, and operative time after adjusting for age (P < .0001), sex (P < .0001), BMI (P < .0001), and operative time (P = .8308). Regarding TKA, mean ambulation was higher for the TXA group than for the no-TXA group at POD-1 (8.36 vs 3.40 feet; P < .0001) and POD-2 (25.81 vs 18.75 feet; P = .0054). The same was true for anterior THA at POD-1 (10.86 vs 3.33 feet; P < .0001) and POD-2 (27.24 vs 13.19 feet; P < .0001) and posterior THA at POD-1 (10.64 vs 3.37 feet; P < .0001) and POD-2 (24.68 vs 12.93 feet; P = .0002). See Table 3.

Intraoperative Blood Loss

There was a significant 3-way interaction of TXA, procedure (P < .0053), and operative time (P < .0001) after adjusting for age (P < .6136), sex (P = .1147), and BMI (P = .6180). Regarding TKA, mean intraoperative blood loss was significantly lower for the TXA group than for the no-TXA group (241.58 vs 287.81 mL; P = .0004). The same was true for anterior THA (352.91 vs 533.79 mL; P < .0001). Regarding posterior THA, there was no significant difference between the TXA and no-TXA groups (326.00 vs 350.16 mL; P = .3246). See Table 4. 

Hemoglobin

There was a significant (P = .0008) 3-way interaction of TXA, procedure, and operative time after adjusting for age (P = .0174), sex (P < .0001), BMI (P = .0007), and operative time (P = .0002). Regarding TKA, postoperative hemoglobin levels were higher for the TXA group than for the no-TXA group at POD-0 (12.10 vs 11.68 g/dL; P = .0135), POD-1 (11.62 vs 10.67 g/dL; P < .0001), and POD-2 (11.02 vs 10.11 g/dL; P < .0001). The same was true for anterior THA at POD-1 (11.03 vs 10.19 g/dL; P = .0034) and POD-2 (10.57 vs 9.64 g/dL; P = .0009) and posterior THA at POD-2 (11.04 vs 10.16 g/dL; P = .0003). See Table 5.

Hematocrit

There was a significant (P < .0006) 3-way interaction of TXA, procedure, and operative time after adjusting for age (P = .1597), sex (P < .0001), BMI (P < .0001), and operative time (P = .0003). Regarding TKA, postoperative hematocrit levels were higher for the TXA group than for the no-TXA group at POD-0 (36.52% vs 34.65%; P < .0001), POD-1 (34.62% vs 31.83%; P < .0001), and POD-2 (33.01% vs 30.20%; P < .0001). The same was true for anterior THA at POD-1 (32.82% vs 30.59%; P = .0037) and POD-2 (31.58% vs 28.61%; P = .0004) and posterior THA at POD-2 (32.93% vs 30.17%; P < .0001). See Table 6.

Postoperative Transfusions 

Of the 477 patients, 25 (5.24%) required a postoperative transfusion. Postoperative transfusions were less likely (P < .0001) required in the TXA group (1.64%, 6/366) than in the no-TXA group (17.12%, 19/111). Given the smaller number of events, a more complex model accounting for clustered data and potential confounders was not used, and the different procedures were not evaluated separately.

Deep Vein Thrombosis and Pulmonary Embolism

Of the 477 patients, 2 developed a DVT, and 5 developed a PE. Both DVTs occurred in the TXA group (2/366, 0.55%; 95% CI, 0.07%-1.96%). Of the 5 PEs, 4 occurred in the TXA group (4/366, 1.09%; 95% CI, 0.30%-2.77%), and 1 occurred in the no-TXA group (1/111, 0.90%; 95% CI, 0.02%-4.92%). Given the exceedingly small number of events, no statistical significance was noted between groups.

Discussion

Orthopedic surgeons carefully balance patient expectations, societal needs, and regulatory mandates while providing excellent care and working under payers’ financial restrictions. The Centers for Medicare & Medicaid Services announced that, starting in 2016, TJAs will be reimbursed in total as a single bundled payment, adding to the need to provide optimal care in a fiscally responsible manner.²¹ Standardized protocols implementing multimodal therapies are pivotal in achieving favorable postoperative outcomes.

Our study results showed that IV-TXA use minimized hemoglobin and hematocrit reductions after TKA, anterior THA, and posterior THA. Postoperative anemia correlates with decreased ambulation ability and performance during the early postoperative period. In general, higher postoperative hemoglobin and hematocrit levels result in improved motor performance and shorter recovery.²² In addition, early ambulation is a validated predictor of favorable TJA outcomes. In our study, for TKA, anterior THA, and posterior THA, ambulation on POD-1 and POD-2 was significantly better for patients who received TXA than for patients who did not.

Transfusion rates were markedly lower for our TXA group than for our no-TXA group (1.64% vs 17.12%), confirming the findings of numerous other studies on outcomes of TJA with TXA.^{2,3,6-12,14,15} Transfusions impede physical therapy and affect hospitalization costs.

Although potential thrombosis-related adverse events remain an endpoint in studies involving TXA, we found a comparably low incidence of postoperative venous thrombosis in our TXA and no-TXA groups (1.09% and 0.90%, respectively). In addition, no patient in either group developed a postoperative arterial thrombosis.

This is the largest single-center study of TXA use in TKA, anterior THA, and posterior THA. The effect of TXA use on postoperative ambulation was not previously found with TJA.

This study had its limitations. First, it was not prospective, randomized, or double-blinded. However, the physical therapists who mobilized patients and recorded ambulation data were blinded to the study and its hypothesis and followed a standardized protocol for all patients. In addition, intraoperative blood loss was recorded by an anesthesiologist using a standardized protocol, and patients received TXA per orthopedic protocol and surgeon preference, without selection bias. Another limitation was that ambulation data were captured only for POD-1 and POD-2 (most patients were discharged by POD-3). However, a goal of the study was to capture immediate postoperative data in order to determine the efficacy of intraoperative TXA. Subsequent studies can determine if this early benefit leads to long-term clinical outcome improvements.

In reducing blood loss and transfusion rates, intra-articular TXA is as efficacious as IV-TXA.^23-25 We anticipate that the improved clinical outcomes found with IV-TXA in our study will be similar with intra-articular TXA, but more study is needed to confirm this hypothesis.

Conclusion

This retrospective cohort study found that use of IV-TXA in TJA improved early ambulation and clinical outcomes (reduced anemia, fewer transfusions) in the initial postoperative period, without producing adverse events.

Take-Home Points

• IV-TXA significantly reduces intraoperative blood loss following TJA.
• Early mobilization correlates with reduced incidence of postoperative complications.
• IV-TXA minimizes postoperative anemia, facilitating improved early ambulation following TJA.
• IV-TXA significantly reduces the need for postoperative transfusions.
• IV-TXA is safe to use with no adverse events noted.

By the year 2020, use of primary total knee arthroplasty (TKA) in the United States will increase an estimated 110%, to 1.375 million procedures annually, and use of primary total hip arthroplasty (THA) will increase an estimated 75%, to more than 500,000 procedures.¹ Minimizing perioperative blood loss and improving early postoperative ambulation both correlate with reduced postoperative morbidity, allowing patients to return to their daily lives expeditiously. 

Tranexamic acid (TXA), a fibrinolytic inhibitor, competitively blocks lysine receptor binding sites of plasminogen, sustaining and stabilizing the fibrin architecture.² TXA must be present to occupy binding sites before plasminogen binds to fibrin, validating the need for preoperative administration so the drug is available early in the fibrinolytic cascade.³ Intravenous (IV) TXA diffuses rapidly into joint fluid and the synovial membrane.⁴ Drug concentration and elimination half-life in joint fluid are equivalent to those in serum. Elimination of TXA occurs by glomerular filtration, with about 30% of a 10-mg/kg dose removed in 1 hour, 55% over the first 3 hours, and 90% within 24 hours of IV administration.⁵

The efficacy of IV-TXA in minimizing total joint arthroplasty (TJA) perioperative blood loss has been proved in small studies and meta-analyses.^6-9 TXA-induced blood conservation decreases or eliminates the need for postoperative transfusion, which can impede valuable, early ambulation.10 In addition, the positive clinical safety profile of TXA supports routine use of TXA in TJA.^6,11-15

The benefits of early ambulation after TJA are well established. Getting patients to walk on the day of surgery is a key part of effective and rapid postoperative rehabilitation. Early mobilization correlates with reduced incidence of venous thrombosis and postoperative complications.¹⁶ In contrast to bed rest, sitting and standing promotes oxygen saturation, which improves tissue healing and minimizes adverse pulmonary events. Oxygen saturation also preserves muscle strength and blood flow, reducing the risk of venous thromboembolism and ulcers. Muscle strength must be maintained so normal gait can be regained.¹⁷ Compared with rehabilitation initiated 48 to 72 hours after TKA, rehabilitation initiated within 24 hours reduced the number of sessions needed to achieve independence and normal gait; in addition, early mobilization improved patient reports of pain after surgery.¹⁸ An evaluation of Denmark registry data revealed that mobilization to walking and use of crutches or canes was achieved earlier when ambulation was initiated on day of surgery.¹⁹ Finally, mobilization on day of surgery and during the immediate postoperative period improved long-term quality of life after TJA.²⁰

We conducted a retrospective cohort study to determine if use of IV-TXA improves early ambulation and reduces blood loss after TKA and anterior and posterior THA. We hypothesized that IV-TXA use would reduce postoperative anemia and improve early ambulation and outcomes without producing adverse events during the immediate postoperative period. TXA reduces bleeding, and reduced incidence of hemarthrosis, wound swelling, and anemia could facilitate ambulation, reduce complications, and shorten recovery in patients who undergo TJA.

Patients and Methods

In February 2014, this retrospective cohort study received Institutional Review Board approval to compare the safety and efficacy of IV-TXA (vs no TXA) in patients who underwent TKA, anterior THA, and posterior THA.

In March 2012, multidisciplinary protocols were standardized to ensure a uniform hospital course for patients at our institution. All patients underwent preoperative testing and evaluation by a nurse practitioner and an anesthesiologist. In March 2013, IV-TXA became our standard of care. TXA use was contraindicated in patients with thromboembolic disease or with hypersensitivity to TXA. Patients without a contraindication were given two 10-mg/kg IV-TXA doses, each administered over 15 to 30 minutes; the first dose was administered before incision, and the second was infused at case close and/or at least 60 minutes after the first dose. Most TKA patients received regional (femoral) anesthesia and analgesia, and most THA patients received spinal or epidural anesthesia and analgesia. In a small percentage of cases, IV analgesia was patient-controlled, as determined by the pain service. There were no significant differences in anesthesia/analgesia modality between the 2 study groups—patients who received TXA and those who did not. Patients were then transitioned to oral opioids for pain management, unless otherwise contraindicated, and were ambulated 4 hours after end of surgery, unless medically unstable. Hematology and chemistry laboratory values were monitored daily during admission.

Patients underwent physical therapy (PT) after surgery and until hospital discharge. Physical therapists blinded to patients’ intraoperative use or no use of TXA measured ambulation. After initial evaluation on postoperative day 0 (POD-0), patients were ambulated twice daily. The daily ambulation distance used for the study was the larger of the 2 daily PT distances (occasionally, patients were unable to participate fully in both sessions). Patients received either enoxaparin or rivaroxaban for postoperative thromboprophylaxis (the anticoagulant used was based on surgeon preference). Enoxaparin was subcutaneously administered at 30 mg every 12 hours for TKA, 40 mg once daily for THA, 30 mg once daily for calculated creatinine clearance under 30 mL/min, or 40 mg every 12 hours for body mass index (BMI) 40 or above. With enoxaparin, therapy duration was 14 days. Oral rivaroxaban was administered at 10 mg once daily for 12 days for TKA and 35 days for THA unless contraindicated.

The primary outcome variables were ambulation measured on POD-1 and POD-2 and intraoperative blood loss. In addition, hemoglobin and hematocrit were measured on POD-0, POD-1, and POD-2. Ambulation was defined as number of feet walked during postoperative hospitalization. To calculate intraoperative blood loss, the anesthesiologist subtracted any saline irrigation volume from the total volume in the suction canister. Also noted were postoperative transfusions and any diagnosis of postoperative venous thromboembolism—specifically, deep vein thrombosis (DVT) or pulmonary embolism (PE).

Demographic and clinical characteristics of the TXA and no-TXA groups were compared using either 2-sample t test (for continuous variables) or χ2 test (for categorical variables).

The ambulation outcome was log-transformed to meet standard assumptions of Gaussian residuals and equality of variance. Means and 95% confidence intervals (CIs) were calculated on the log scale and were anti-logged so the results could be presented in their original units. 

A linear mixed model was used to model intraoperative blood loss as a function of group (TXA, no TXA), procedure (TKA, anterior THA, posterior THA), and potential confounders (age, sex, BMI, operative time).

Linear mixed models for repeated measures were used to compare outcomes (hemoglobin, hematocrit) between groups (TXA, no TXA) and procedures (TKA, anterior THA, posterior THA) and to compare changes in outcomes over time. Group, procedure, and operative time interactions were explored. Potential confounders (age, sex, BMI, operative time) were included in the model as well.

A χ2 test was used to compare the groups (TXA, no TXA) on postoperative blood transfusion (yes, no). Given the smaller number of events, a more complex model accounting for clustered data and potential confounders was not used. Need for transfusion was clinically assessed case by case. Symptomatic anemia (dyspnea on exertion, headaches, tachycardia) was used as the primary indication for transfusion once hemoglobin fell below 8 g/dL or hematocrit below 24%. Number of patients with a postoperative thrombus formation was minimal. Therefore, this outcome was described with summary statistics and was not formally analyzed.

Results

Of the 477 patients who underwent TJAs (275 TKAs, 98 anterior THAs, 104 posterior THAs; all unilateral), 111 did not receive TXA (June 2012-February 2013), and 366 received TXA (March 2013-January 2014). Other than for the addition of IV-TXA, the same standardized protocols instituted in March 2012 continued throughout the study period. The difference in sample size between the TXA and no-TXA groups was not statistically significant and did not influence the outcome measures.

Ambulation

There was a significant (P = .0066) 3-way interaction of TXA, procedure, and operative time after adjusting for age (P < .0001), sex (P < .0001), BMI (P < .0001), and operative time (P = .8308). Regarding TKA, mean ambulation was higher for the TXA group than for the no-TXA group at POD-1 (8.36 vs 3.40 feet; P < .0001) and POD-2 (25.81 vs 18.75 feet; P = .0054). The same was true for anterior THA at POD-1 (10.86 vs 3.33 feet; P < .0001) and POD-2 (27.24 vs 13.19 feet; P < .0001) and posterior THA at POD-1 (10.64 vs 3.37 feet; P < .0001) and POD-2 (24.68 vs 12.93 feet; P = .0002). See Table 3.

Intraoperative Blood Loss

There was a significant 3-way interaction of TXA, procedure (P < .0053), and operative time (P < .0001) after adjusting for age (P < .6136), sex (P = .1147), and BMI (P = .6180). Regarding TKA, mean intraoperative blood loss was significantly lower for the TXA group than for the no-TXA group (241.58 vs 287.81 mL; P = .0004). The same was true for anterior THA (352.91 vs 533.79 mL; P < .0001). Regarding posterior THA, there was no significant difference between the TXA and no-TXA groups (326.00 vs 350.16 mL; P = .3246). See Table 4. 

Hemoglobin

There was a significant (P = .0008) 3-way interaction of TXA, procedure, and operative time after adjusting for age (P = .0174), sex (P < .0001), BMI (P = .0007), and operative time (P = .0002). Regarding TKA, postoperative hemoglobin levels were higher for the TXA group than for the no-TXA group at POD-0 (12.10 vs 11.68 g/dL; P = .0135), POD-1 (11.62 vs 10.67 g/dL; P < .0001), and POD-2 (11.02 vs 10.11 g/dL; P < .0001). The same was true for anterior THA at POD-1 (11.03 vs 10.19 g/dL; P = .0034) and POD-2 (10.57 vs 9.64 g/dL; P = .0009) and posterior THA at POD-2 (11.04 vs 10.16 g/dL; P = .0003). See Table 5.

Hematocrit

There was a significant (P < .0006) 3-way interaction of TXA, procedure, and operative time after adjusting for age (P = .1597), sex (P < .0001), BMI (P < .0001), and operative time (P = .0003). Regarding TKA, postoperative hematocrit levels were higher for the TXA group than for the no-TXA group at POD-0 (36.52% vs 34.65%; P < .0001), POD-1 (34.62% vs 31.83%; P < .0001), and POD-2 (33.01% vs 30.20%; P < .0001). The same was true for anterior THA at POD-1 (32.82% vs 30.59%; P = .0037) and POD-2 (31.58% vs 28.61%; P = .0004) and posterior THA at POD-2 (32.93% vs 30.17%; P < .0001). See Table 6.

Postoperative Transfusions 

Of the 477 patients, 25 (5.24%) required a postoperative transfusion. Postoperative transfusions were less likely (P < .0001) required in the TXA group (1.64%, 6/366) than in the no-TXA group (17.12%, 19/111). Given the smaller number of events, a more complex model accounting for clustered data and potential confounders was not used, and the different procedures were not evaluated separately.

Deep Vein Thrombosis and Pulmonary Embolism

Of the 477 patients, 2 developed a DVT, and 5 developed a PE. Both DVTs occurred in the TXA group (2/366, 0.55%; 95% CI, 0.07%-1.96%). Of the 5 PEs, 4 occurred in the TXA group (4/366, 1.09%; 95% CI, 0.30%-2.77%), and 1 occurred in the no-TXA group (1/111, 0.90%; 95% CI, 0.02%-4.92%). Given the exceedingly small number of events, no statistical significance was noted between groups.

Discussion

Orthopedic surgeons carefully balance patient expectations, societal needs, and regulatory mandates while providing excellent care and working under payers’ financial restrictions. The Centers for Medicare & Medicaid Services announced that, starting in 2016, TJAs will be reimbursed in total as a single bundled payment, adding to the need to provide optimal care in a fiscally responsible manner.²¹ Standardized protocols implementing multimodal therapies are pivotal in achieving favorable postoperative outcomes.

Our study results showed that IV-TXA use minimized hemoglobin and hematocrit reductions after TKA, anterior THA, and posterior THA. Postoperative anemia correlates with decreased ambulation ability and performance during the early postoperative period. In general, higher postoperative hemoglobin and hematocrit levels result in improved motor performance and shorter recovery.²² In addition, early ambulation is a validated predictor of favorable TJA outcomes. In our study, for TKA, anterior THA, and posterior THA, ambulation on POD-1 and POD-2 was significantly better for patients who received TXA than for patients who did not.

Transfusion rates were markedly lower for our TXA group than for our no-TXA group (1.64% vs 17.12%), confirming the findings of numerous other studies on outcomes of TJA with TXA.^{2,3,6-12,14,15} Transfusions impede physical therapy and affect hospitalization costs.

Although potential thrombosis-related adverse events remain an endpoint in studies involving TXA, we found a comparably low incidence of postoperative venous thrombosis in our TXA and no-TXA groups (1.09% and 0.90%, respectively). In addition, no patient in either group developed a postoperative arterial thrombosis.

This is the largest single-center study of TXA use in TKA, anterior THA, and posterior THA. The effect of TXA use on postoperative ambulation was not previously found with TJA.

This study had its limitations. First, it was not prospective, randomized, or double-blinded. However, the physical therapists who mobilized patients and recorded ambulation data were blinded to the study and its hypothesis and followed a standardized protocol for all patients. In addition, intraoperative blood loss was recorded by an anesthesiologist using a standardized protocol, and patients received TXA per orthopedic protocol and surgeon preference, without selection bias. Another limitation was that ambulation data were captured only for POD-1 and POD-2 (most patients were discharged by POD-3). However, a goal of the study was to capture immediate postoperative data in order to determine the efficacy of intraoperative TXA. Subsequent studies can determine if this early benefit leads to long-term clinical outcome improvements.

In reducing blood loss and transfusion rates, intra-articular TXA is as efficacious as IV-TXA.^23-25 We anticipate that the improved clinical outcomes found with IV-TXA in our study will be similar with intra-articular TXA, but more study is needed to confirm this hypothesis.

Conclusion

This retrospective cohort study found that use of IV-TXA in TJA improved early ambulation and clinical outcomes (reduced anemia, fewer transfusions) in the initial postoperative period, without producing adverse events.

Take-Home Points

• Analysis of patients in the Medicare database showed that each successive ESI decreased the risk of an osteoporotic spine fracture by 2%, and that each successive LJSI decreases it by 4%.

• Although statistically significant, this may not be clinically relevant.

• Successive ESI did not influence the risk of developing an osteoporotic hip or wrist fracture, but that each additional LJSI reduced the risk.

• Prolonged steroid exposure was found to increase the risk of spine fracture for ESI and LJSI patients.

• Acute exposure to exogenous steroids via the epidural space, transforaminal space, or large joints does not seem to increase the risk of an osteoporotic fracture of the spine, hip, or wrist.

Epidural steroid injections (ESIs) are widely used in the nonoperative treatment of low back pain, radicular leg pain, and spinal stenosis. The treatment rationale is that locally injected anti-inflammatory drugs, such as steroids, reduce inflammation by inhibiting formation and release of inflammatory cytokines, leading to pain reduction.^1,2 According to 4 systematic reviews, the best available evidence of the efficacy of ESIs is less than robust.^3-6 These reviews were limited by the heterogeneity of patient selection, delivery mode, type and dose of steroid used, number and frequency of ESIs, and outcome measures.

The association of chronic oral steroid use and the development of osteoporosis was previously established.^7,8 One concern is that acute exposure to steroids in the form of lumbar ESIs may also lead to osteoporosis and then a pathologic fracture of the vertebra. Several studies have found no association between bone mineral density and cumulative steroid dose,^9,10 mean number of ESIs, or duration of ESIs,¹⁰ though other studies have found lower bone mineral density in postmenopausal women treated with ESIs.^11-13

In a study of 3000 ESI patients propensity-matched to a non-ESI cohort, Mandel and colleagues¹⁴ found that each successive ESI increased the risk of osteoporotic spine fracture by 21%. This clinically relevant 21% increased risk might lead physicians to stop prescribing or using this intervention. However, the association between osteoporotic fractures and other types of steroid injections remains poorly understood and underinvestigated. 

To further evaluate the relationship between steroid injections and osteoporotic fracture risk, we analyzed Medicare administrative claims data on both large-joint steroid injections (LJSIs) into knee and hip and transforaminal steroid injections (TSIs), as well as osteoporotic hip and wrist fractures. Our hypothesis was that a systemic effect of steroid injections would increase fracture risk in all skeletal locations regardless of injection site, whereas a local effect would produce a disproportionate increased risk of spine fracture with spine injection.

Materials and Methods

Medicare is a publicly funded US health insurance program for people 65 years old or older, people under age 65 years with certain disabilities, and people (any age) with end-stage renal disease or amyotrophic lateral sclerosis. The 5% Medicare Part B (physician, carrier) dataset contains individual claims records for a random sample of Medicare beneficiaries (~2.4 million enrollees). Patients who received steroid injections were identified from 5% Medicare claims made between January 1, 2004 and December 31, 2011. LJSIs were identified by Current Procedural Terminology (CPT) code 20610 and any of 16 other CPT codes: J0702, J1020, J1030, J1040, J1094, J1100, J1700, J1710, J1720, J2650, J2920, J2930, J3300, J3301, J3302, and J3303. ESIs were identified by CPT code 62310, 62311, 62318, or 62319, and TSIs by CPT code 64479, 64480, 64483, or 64484. Patients were followed in their initial injection cohort. For example, a patient who received an ESI initially and later received an LJSI remained in the ESI cohort.

Several groups of patients were excluded from the study: those who received Medicare coverage because of their age (under 65 years) and disabilities; those who received Medicare health benefits through health maintenance organizations (healthcare expenses were not submitted to the Centers for Medicare & Medicaid Services for payment, and therefore claims were not in the database or were incomplete); those with a prior claim history of <12 months (incomplete comorbidity history); and those who received a diagnosis of osteoporotic fracture (International Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM] code 733.1x) before the initial steroid injection.

We determined the incidence of osteoporotic wrist, hip, and spine fractures within 1, 2, and 8 years after LJSI, ESI, and TSI. Wrist, hip, and spine fractures were identified by ICD-9-CM diagnosis codes 733.12, 733.13, and 733.14, respectively. We also determined the number of steroid injections given before wrist, hip, or spine fracture or, if no fracture occurred, before death or the end of the data period.

Statistical Analysis

Multivariate Cox regression analysis was performed to evaluate the risk factors for wrist, spine, and hip fractures. The covariates in this model included age, sex, race, census region, Medicare buy-in status, Charlson Comorbidity Index (CCI),¹⁵ year, and number of steroid injections before fracture, death, or end of data period. Medicare buy-in status, which indicates whether the beneficiary received financial assistance in paying insurance premiums, was used as a proxy for socioeconomic status. CCI is used as a composite score of a patient’s general health status in terms of comorbidities.^15,16 Four previously established categories¹⁷ were used to group CCIs in this study: 0 (none), 1 to 2 (low), 3 to 4 (moderate), and 5 or more (high). In addition, several diagnoses made within the 12 months before initial steroid injection were considered: osteoporosis (ICD-9-CM codes 733.0x, V82.81), Cushing syndrome (ICD-9-CM code 255.0), long-term (current) use of bisphosphonates (ICD-9-CM code V58.68), asymptomatic postmenopausal status (ICD-9-CM code V49.81), postmenopausal hormone replacement therapy (ICD-9-CM code V07.4), and long-term (current) use of steroids (ICD-9-CM code V58.65). The comparison of relative risk between any groups was reported as the adjusted hazard ratio (AHR), which is the ratio of the hazard rates of that particular outcome, taking into account inherent patient characteristics such as age, sex, and race as covariates. AHR of 1 corresponds to equivalent risk, AHR of >1 to elevated risk, and AHR of <1 to reduced risk.

Results

Using the 5% Medicare data for 2004 to 2011, we identified 275,999 Medicare beneficiaries who underwent LJSI, 93,943 who underwent ESI, and 32,311 who underwent TSI. During this period, TSI use increased, ESI use decreased, and LJSI use was relatively stable (Figure).

The risk for osteoporotic spine fracture 1, 2, and 8 years after ESI, TSI, or LJSI was affected by age, race, sex, and CCI (P < .001 for all; Tables 2-4).

The risk for osteoporotic hip fracture after 1 and 2 years was affected by age and number of LJSIs and TSIs but not by number of ESIs. Sex and CCI were also risk factors for hip fracture at 1 and 2 years for ESI and LJSI patients, as was race for LJSI patients. Risk for osteoporotic wrist fracture at 1 and 2 years was affected by sex and race for ESI and LJSI patients; age, race, CCI, and long-term steroid use were risk factors for TSI patients at all time points. Higher number of LJSIs, but not ESIs or TSIs, was associated with lower wrist fracture risk.

Discussion

ESIs continue to be used in the nonoperative treatment of low back pain, radicular leg pain, and spinal stenosis. Although the present study found ESI use increased in the Medicare population between 1994 and 2001,¹⁸ the trend is reversing, decreasing by 25%, with rates of 264 per 10,000 Medicare enrollees in 2004 and 194 per 10,000 enrollees in 2011. ESI use may have changed after systematic reviews revealed there was no clear evidence of the efficacy of ESIs in managing low back pain and radicular leg pain^3,5,6 or spinal stenosis.⁴

Nevertheless, ESIs are widely used because of the perceived benefit balanced against the perceived rarity of adverse events.⁶ Even if patients recognize a low likelihood of significant benefit, they may accept ESI as preferable to surgery. In addition, most private payers require extensive nonoperative treatment before they will approve surgery as a treatment option.

In a study by Mandel and colleagues,¹⁴ ESI increased the risk of vertebral compression fractures by 21%, which in turn increased the risk of death.¹⁹ If accurate, these findings obviously would challenge the perception that ESI is a low-risk intervention. In contrast to the Mandel study,¹⁴ the present analysis of the Medicare population revealed no clinically relevant change in risk of osteoporotic spine fracture with each successive ESI after the initial injection. After the initial injection, each successive ESI decreased the relative risk of osteoporotic spine fracture by 2%, and each successive LJSI decreased it by 4%. Although statistically significant, the small change in relative risk may not be clinically relevant. However, taken cumulatively over a number of successive injections, these effects may be clinically relevant.

The data also showed that, after the initial injection, each successive ESI had no effect on risk of osteoporotic hip or wrist fracture, and each successive LJSI reduced the risk. Similar to earlier findings,^20,21 long-term steroid use increased the risk of spine fracture in ESI and LJSI patients. Prolonged exposure to steroids may be necessary to reduce bone formation and increase bone breakdown.¹²

Although the study by Mandel and colleagues¹⁴ and our study both used administrative databases and survival analysis methods, conclusions differed. First, Mandel and colleagues¹⁴ used a study inclusion criterion of spine-related steroid injections, whereas we used a criterion of any steroid injection. Second, they used 50 years as the lower age for study inclusion, and we used 65 years. Third, to control for patients who had osteoporosis before study entry, they excluded those who had a fracture in an adjacent vertebra after kyphoplasty and vertebroplasty. It is unclear if patients who had osteoporotic fractures at other sites were excluded as well. Thus, the 2 cohorts may not be directly comparable.

Whereas Mandel and colleagues¹⁴ based their definition of osteoporotic spine fracture on a keyword search of a radiology database, we used a specific reportable ICD-9-CM diagnosis code. As a result, they may have overreported osteoporotic spine fractures, and we may have underreported. Finally, our sample was much larger than theirs. Given the relative rarity of osteoporotic fractures, a study with a larger sample may have more power to detect differences. In addition, unlike Mandel and colleagues,¹⁴ we focused on an injection cohort. We did not include or make comparisons with a no-injection cohort because our study hypothesis involved the potential systemic effects of steroid injections based on injection site. Although chronic steroid use was found to have a significant effect in our study, it is unclear to what extent the diagnosis code was used, during the comorbidity assessment or only in the event of steroid-related complications.

Our study also found that, after the initial injection, each successive LJSI decreased the risk of osteoporotic wrist fracture by 10%, and each successive TSI decreased the risk of osteoporotic hip fracture by 5%. It is plausible these injections allowed improved mobility, mitigating the effects of osteoporosis induced by inactivity and lack of resistance training. It is also possible that improved mobility limited falls.

In summary, this analysis of the Medicare claims database revealed that ESI, TSI, and LJSI decreased osteoporotic spine fracture risk. However, the effect was small and may not be clinically meaningful. After the initial injection, successive ESIs had no effect on the risk of osteoporotic hip or wrist fracture, and successive LJSIs reduced the risk of osteoporotic wrist fracture, perhaps because of improved mobility. Prolonged oral steroid use increased spine fracture risk in ESI and LJSI patients. More studies are needed to evaluate the risk-benefit profile of steroid injections.

Take-Home Points

• Analysis of patients in the Medicare database showed that each successive ESI decreased the risk of an osteoporotic spine fracture by 2%, and that each successive LJSI decreases it by 4%.

• Although statistically significant, this may not be clinically relevant.

• Successive ESI did not influence the risk of developing an osteoporotic hip or wrist fracture, but that each additional LJSI reduced the risk.

• Prolonged steroid exposure was found to increase the risk of spine fracture for ESI and LJSI patients.

• Acute exposure to exogenous steroids via the epidural space, transforaminal space, or large joints does not seem to increase the risk of an osteoporotic fracture of the spine, hip, or wrist.

Epidural steroid injections (ESIs) are widely used in the nonoperative treatment of low back pain, radicular leg pain, and spinal stenosis. The treatment rationale is that locally injected anti-inflammatory drugs, such as steroids, reduce inflammation by inhibiting formation and release of inflammatory cytokines, leading to pain reduction.^1,2 According to 4 systematic reviews, the best available evidence of the efficacy of ESIs is less than robust.^3-6 These reviews were limited by the heterogeneity of patient selection, delivery mode, type and dose of steroid used, number and frequency of ESIs, and outcome measures.

The association of chronic oral steroid use and the development of osteoporosis was previously established.^7,8 One concern is that acute exposure to steroids in the form of lumbar ESIs may also lead to osteoporosis and then a pathologic fracture of the vertebra. Several studies have found no association between bone mineral density and cumulative steroid dose,^9,10 mean number of ESIs, or duration of ESIs,¹⁰ though other studies have found lower bone mineral density in postmenopausal women treated with ESIs.^11-13

In a study of 3000 ESI patients propensity-matched to a non-ESI cohort, Mandel and colleagues¹⁴ found that each successive ESI increased the risk of osteoporotic spine fracture by 21%. This clinically relevant 21% increased risk might lead physicians to stop prescribing or using this intervention. However, the association between osteoporotic fractures and other types of steroid injections remains poorly understood and underinvestigated. 

To further evaluate the relationship between steroid injections and osteoporotic fracture risk, we analyzed Medicare administrative claims data on both large-joint steroid injections (LJSIs) into knee and hip and transforaminal steroid injections (TSIs), as well as osteoporotic hip and wrist fractures. Our hypothesis was that a systemic effect of steroid injections would increase fracture risk in all skeletal locations regardless of injection site, whereas a local effect would produce a disproportionate increased risk of spine fracture with spine injection.

Materials and Methods

Medicare is a publicly funded US health insurance program for people 65 years old or older, people under age 65 years with certain disabilities, and people (any age) with end-stage renal disease or amyotrophic lateral sclerosis. The 5% Medicare Part B (physician, carrier) dataset contains individual claims records for a random sample of Medicare beneficiaries (~2.4 million enrollees). Patients who received steroid injections were identified from 5% Medicare claims made between January 1, 2004 and December 31, 2011. LJSIs were identified by Current Procedural Terminology (CPT) code 20610 and any of 16 other CPT codes: J0702, J1020, J1030, J1040, J1094, J1100, J1700, J1710, J1720, J2650, J2920, J2930, J3300, J3301, J3302, and J3303. ESIs were identified by CPT code 62310, 62311, 62318, or 62319, and TSIs by CPT code 64479, 64480, 64483, or 64484. Patients were followed in their initial injection cohort. For example, a patient who received an ESI initially and later received an LJSI remained in the ESI cohort.

Several groups of patients were excluded from the study: those who received Medicare coverage because of their age (under 65 years) and disabilities; those who received Medicare health benefits through health maintenance organizations (healthcare expenses were not submitted to the Centers for Medicare & Medicaid Services for payment, and therefore claims were not in the database or were incomplete); those with a prior claim history of <12 months (incomplete comorbidity history); and those who received a diagnosis of osteoporotic fracture (International Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM] code 733.1x) before the initial steroid injection.

We determined the incidence of osteoporotic wrist, hip, and spine fractures within 1, 2, and 8 years after LJSI, ESI, and TSI. Wrist, hip, and spine fractures were identified by ICD-9-CM diagnosis codes 733.12, 733.13, and 733.14, respectively. We also determined the number of steroid injections given before wrist, hip, or spine fracture or, if no fracture occurred, before death or the end of the data period.

Statistical Analysis

Multivariate Cox regression analysis was performed to evaluate the risk factors for wrist, spine, and hip fractures. The covariates in this model included age, sex, race, census region, Medicare buy-in status, Charlson Comorbidity Index (CCI),¹⁵ year, and number of steroid injections before fracture, death, or end of data period. Medicare buy-in status, which indicates whether the beneficiary received financial assistance in paying insurance premiums, was used as a proxy for socioeconomic status. CCI is used as a composite score of a patient’s general health status in terms of comorbidities.^15,16 Four previously established categories¹⁷ were used to group CCIs in this study: 0 (none), 1 to 2 (low), 3 to 4 (moderate), and 5 or more (high). In addition, several diagnoses made within the 12 months before initial steroid injection were considered: osteoporosis (ICD-9-CM codes 733.0x, V82.81), Cushing syndrome (ICD-9-CM code 255.0), long-term (current) use of bisphosphonates (ICD-9-CM code V58.68), asymptomatic postmenopausal status (ICD-9-CM code V49.81), postmenopausal hormone replacement therapy (ICD-9-CM code V07.4), and long-term (current) use of steroids (ICD-9-CM code V58.65). The comparison of relative risk between any groups was reported as the adjusted hazard ratio (AHR), which is the ratio of the hazard rates of that particular outcome, taking into account inherent patient characteristics such as age, sex, and race as covariates. AHR of 1 corresponds to equivalent risk, AHR of >1 to elevated risk, and AHR of <1 to reduced risk.

Results

Using the 5% Medicare data for 2004 to 2011, we identified 275,999 Medicare beneficiaries who underwent LJSI, 93,943 who underwent ESI, and 32,311 who underwent TSI. During this period, TSI use increased, ESI use decreased, and LJSI use was relatively stable (Figure).

The risk for osteoporotic spine fracture 1, 2, and 8 years after ESI, TSI, or LJSI was affected by age, race, sex, and CCI (P < .001 for all; Tables 2-4).

The risk for osteoporotic hip fracture after 1 and 2 years was affected by age and number of LJSIs and TSIs but not by number of ESIs. Sex and CCI were also risk factors for hip fracture at 1 and 2 years for ESI and LJSI patients, as was race for LJSI patients. Risk for osteoporotic wrist fracture at 1 and 2 years was affected by sex and race for ESI and LJSI patients; age, race, CCI, and long-term steroid use were risk factors for TSI patients at all time points. Higher number of LJSIs, but not ESIs or TSIs, was associated with lower wrist fracture risk.

Discussion

ESIs continue to be used in the nonoperative treatment of low back pain, radicular leg pain, and spinal stenosis. Although the present study found ESI use increased in the Medicare population between 1994 and 2001,¹⁸ the trend is reversing, decreasing by 25%, with rates of 264 per 10,000 Medicare enrollees in 2004 and 194 per 10,000 enrollees in 2011. ESI use may have changed after systematic reviews revealed there was no clear evidence of the efficacy of ESIs in managing low back pain and radicular leg pain^3,5,6 or spinal stenosis.⁴

Nevertheless, ESIs are widely used because of the perceived benefit balanced against the perceived rarity of adverse events.⁶ Even if patients recognize a low likelihood of significant benefit, they may accept ESI as preferable to surgery. In addition, most private payers require extensive nonoperative treatment before they will approve surgery as a treatment option.

In a study by Mandel and colleagues,¹⁴ ESI increased the risk of vertebral compression fractures by 21%, which in turn increased the risk of death.¹⁹ If accurate, these findings obviously would challenge the perception that ESI is a low-risk intervention. In contrast to the Mandel study,¹⁴ the present analysis of the Medicare population revealed no clinically relevant change in risk of osteoporotic spine fracture with each successive ESI after the initial injection. After the initial injection, each successive ESI decreased the relative risk of osteoporotic spine fracture by 2%, and each successive LJSI decreased it by 4%. Although statistically significant, the small change in relative risk may not be clinically relevant. However, taken cumulatively over a number of successive injections, these effects may be clinically relevant.

The data also showed that, after the initial injection, each successive ESI had no effect on risk of osteoporotic hip or wrist fracture, and each successive LJSI reduced the risk. Similar to earlier findings,^20,21 long-term steroid use increased the risk of spine fracture in ESI and LJSI patients. Prolonged exposure to steroids may be necessary to reduce bone formation and increase bone breakdown.¹²

Although the study by Mandel and colleagues¹⁴ and our study both used administrative databases and survival analysis methods, conclusions differed. First, Mandel and colleagues¹⁴ used a study inclusion criterion of spine-related steroid injections, whereas we used a criterion of any steroid injection. Second, they used 50 years as the lower age for study inclusion, and we used 65 years. Third, to control for patients who had osteoporosis before study entry, they excluded those who had a fracture in an adjacent vertebra after kyphoplasty and vertebroplasty. It is unclear if patients who had osteoporotic fractures at other sites were excluded as well. Thus, the 2 cohorts may not be directly comparable.

Whereas Mandel and colleagues¹⁴ based their definition of osteoporotic spine fracture on a keyword search of a radiology database, we used a specific reportable ICD-9-CM diagnosis code. As a result, they may have overreported osteoporotic spine fractures, and we may have underreported. Finally, our sample was much larger than theirs. Given the relative rarity of osteoporotic fractures, a study with a larger sample may have more power to detect differences. In addition, unlike Mandel and colleagues,¹⁴ we focused on an injection cohort. We did not include or make comparisons with a no-injection cohort because our study hypothesis involved the potential systemic effects of steroid injections based on injection site. Although chronic steroid use was found to have a significant effect in our study, it is unclear to what extent the diagnosis code was used, during the comorbidity assessment or only in the event of steroid-related complications.

Our study also found that, after the initial injection, each successive LJSI decreased the risk of osteoporotic wrist fracture by 10%, and each successive TSI decreased the risk of osteoporotic hip fracture by 5%. It is plausible these injections allowed improved mobility, mitigating the effects of osteoporosis induced by inactivity and lack of resistance training. It is also possible that improved mobility limited falls.

In summary, this analysis of the Medicare claims database revealed that ESI, TSI, and LJSI decreased osteoporotic spine fracture risk. However, the effect was small and may not be clinically meaningful. After the initial injection, successive ESIs had no effect on the risk of osteoporotic hip or wrist fracture, and successive LJSIs reduced the risk of osteoporotic wrist fracture, perhaps because of improved mobility. Prolonged oral steroid use increased spine fracture risk in ESI and LJSI patients. More studies are needed to evaluate the risk-benefit profile of steroid injections.

Take-Home Points

• Analysis of patients in the Medicare database showed that each successive ESI decreased the risk of an osteoporotic spine fracture by 2%, and that each successive LJSI decreases it by 4%.

• Although statistically significant, this may not be clinically relevant.

• Successive ESI did not influence the risk of developing an osteoporotic hip or wrist fracture, but that each additional LJSI reduced the risk.

• Prolonged steroid exposure was found to increase the risk of spine fracture for ESI and LJSI patients.

• Acute exposure to exogenous steroids via the epidural space, transforaminal space, or large joints does not seem to increase the risk of an osteoporotic fracture of the spine, hip, or wrist.

Epidural steroid injections (ESIs) are widely used in the nonoperative treatment of low back pain, radicular leg pain, and spinal stenosis. The treatment rationale is that locally injected anti-inflammatory drugs, such as steroids, reduce inflammation by inhibiting formation and release of inflammatory cytokines, leading to pain reduction.^1,2 According to 4 systematic reviews, the best available evidence of the efficacy of ESIs is less than robust.^3-6 These reviews were limited by the heterogeneity of patient selection, delivery mode, type and dose of steroid used, number and frequency of ESIs, and outcome measures.

The association of chronic oral steroid use and the development of osteoporosis was previously established.^7,8 One concern is that acute exposure to steroids in the form of lumbar ESIs may also lead to osteoporosis and then a pathologic fracture of the vertebra. Several studies have found no association between bone mineral density and cumulative steroid dose,^9,10 mean number of ESIs, or duration of ESIs,¹⁰ though other studies have found lower bone mineral density in postmenopausal women treated with ESIs.^11-13

In a study of 3000 ESI patients propensity-matched to a non-ESI cohort, Mandel and colleagues¹⁴ found that each successive ESI increased the risk of osteoporotic spine fracture by 21%. This clinically relevant 21% increased risk might lead physicians to stop prescribing or using this intervention. However, the association between osteoporotic fractures and other types of steroid injections remains poorly understood and underinvestigated. 

To further evaluate the relationship between steroid injections and osteoporotic fracture risk, we analyzed Medicare administrative claims data on both large-joint steroid injections (LJSIs) into knee and hip and transforaminal steroid injections (TSIs), as well as osteoporotic hip and wrist fractures. Our hypothesis was that a systemic effect of steroid injections would increase fracture risk in all skeletal locations regardless of injection site, whereas a local effect would produce a disproportionate increased risk of spine fracture with spine injection.

Materials and Methods

Medicare is a publicly funded US health insurance program for people 65 years old or older, people under age 65 years with certain disabilities, and people (any age) with end-stage renal disease or amyotrophic lateral sclerosis. The 5% Medicare Part B (physician, carrier) dataset contains individual claims records for a random sample of Medicare beneficiaries (~2.4 million enrollees). Patients who received steroid injections were identified from 5% Medicare claims made between January 1, 2004 and December 31, 2011. LJSIs were identified by Current Procedural Terminology (CPT) code 20610 and any of 16 other CPT codes: J0702, J1020, J1030, J1040, J1094, J1100, J1700, J1710, J1720, J2650, J2920, J2930, J3300, J3301, J3302, and J3303. ESIs were identified by CPT code 62310, 62311, 62318, or 62319, and TSIs by CPT code 64479, 64480, 64483, or 64484. Patients were followed in their initial injection cohort. For example, a patient who received an ESI initially and later received an LJSI remained in the ESI cohort.

Several groups of patients were excluded from the study: those who received Medicare coverage because of their age (under 65 years) and disabilities; those who received Medicare health benefits through health maintenance organizations (healthcare expenses were not submitted to the Centers for Medicare & Medicaid Services for payment, and therefore claims were not in the database or were incomplete); those with a prior claim history of <12 months (incomplete comorbidity history); and those who received a diagnosis of osteoporotic fracture (International Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM] code 733.1x) before the initial steroid injection.

We determined the incidence of osteoporotic wrist, hip, and spine fractures within 1, 2, and 8 years after LJSI, ESI, and TSI. Wrist, hip, and spine fractures were identified by ICD-9-CM diagnosis codes 733.12, 733.13, and 733.14, respectively. We also determined the number of steroid injections given before wrist, hip, or spine fracture or, if no fracture occurred, before death or the end of the data period.

Statistical Analysis

Multivariate Cox regression analysis was performed to evaluate the risk factors for wrist, spine, and hip fractures. The covariates in this model included age, sex, race, census region, Medicare buy-in status, Charlson Comorbidity Index (CCI),¹⁵ year, and number of steroid injections before fracture, death, or end of data period. Medicare buy-in status, which indicates whether the beneficiary received financial assistance in paying insurance premiums, was used as a proxy for socioeconomic status. CCI is used as a composite score of a patient’s general health status in terms of comorbidities.^15,16 Four previously established categories¹⁷ were used to group CCIs in this study: 0 (none), 1 to 2 (low), 3 to 4 (moderate), and 5 or more (high). In addition, several diagnoses made within the 12 months before initial steroid injection were considered: osteoporosis (ICD-9-CM codes 733.0x, V82.81), Cushing syndrome (ICD-9-CM code 255.0), long-term (current) use of bisphosphonates (ICD-9-CM code V58.68), asymptomatic postmenopausal status (ICD-9-CM code V49.81), postmenopausal hormone replacement therapy (ICD-9-CM code V07.4), and long-term (current) use of steroids (ICD-9-CM code V58.65). The comparison of relative risk between any groups was reported as the adjusted hazard ratio (AHR), which is the ratio of the hazard rates of that particular outcome, taking into account inherent patient characteristics such as age, sex, and race as covariates. AHR of 1 corresponds to equivalent risk, AHR of >1 to elevated risk, and AHR of <1 to reduced risk.

Results

Using the 5% Medicare data for 2004 to 2011, we identified 275,999 Medicare beneficiaries who underwent LJSI, 93,943 who underwent ESI, and 32,311 who underwent TSI. During this period, TSI use increased, ESI use decreased, and LJSI use was relatively stable (Figure).

The risk for osteoporotic spine fracture 1, 2, and 8 years after ESI, TSI, or LJSI was affected by age, race, sex, and CCI (P < .001 for all; Tables 2-4).

The risk for osteoporotic hip fracture after 1 and 2 years was affected by age and number of LJSIs and TSIs but not by number of ESIs. Sex and CCI were also risk factors for hip fracture at 1 and 2 years for ESI and LJSI patients, as was race for LJSI patients. Risk for osteoporotic wrist fracture at 1 and 2 years was affected by sex and race for ESI and LJSI patients; age, race, CCI, and long-term steroid use were risk factors for TSI patients at all time points. Higher number of LJSIs, but not ESIs or TSIs, was associated with lower wrist fracture risk.

Discussion

ESIs continue to be used in the nonoperative treatment of low back pain, radicular leg pain, and spinal stenosis. Although the present study found ESI use increased in the Medicare population between 1994 and 2001,¹⁸ the trend is reversing, decreasing by 25%, with rates of 264 per 10,000 Medicare enrollees in 2004 and 194 per 10,000 enrollees in 2011. ESI use may have changed after systematic reviews revealed there was no clear evidence of the efficacy of ESIs in managing low back pain and radicular leg pain^3,5,6 or spinal stenosis.⁴

Nevertheless, ESIs are widely used because of the perceived benefit balanced against the perceived rarity of adverse events.⁶ Even if patients recognize a low likelihood of significant benefit, they may accept ESI as preferable to surgery. In addition, most private payers require extensive nonoperative treatment before they will approve surgery as a treatment option.

In a study by Mandel and colleagues,¹⁴ ESI increased the risk of vertebral compression fractures by 21%, which in turn increased the risk of death.¹⁹ If accurate, these findings obviously would challenge the perception that ESI is a low-risk intervention. In contrast to the Mandel study,¹⁴ the present analysis of the Medicare population revealed no clinically relevant change in risk of osteoporotic spine fracture with each successive ESI after the initial injection. After the initial injection, each successive ESI decreased the relative risk of osteoporotic spine fracture by 2%, and each successive LJSI decreased it by 4%. Although statistically significant, the small change in relative risk may not be clinically relevant. However, taken cumulatively over a number of successive injections, these effects may be clinically relevant.

The data also showed that, after the initial injection, each successive ESI had no effect on risk of osteoporotic hip or wrist fracture, and each successive LJSI reduced the risk. Similar to earlier findings,^20,21 long-term steroid use increased the risk of spine fracture in ESI and LJSI patients. Prolonged exposure to steroids may be necessary to reduce bone formation and increase bone breakdown.¹²

Although the study by Mandel and colleagues¹⁴ and our study both used administrative databases and survival analysis methods, conclusions differed. First, Mandel and colleagues¹⁴ used a study inclusion criterion of spine-related steroid injections, whereas we used a criterion of any steroid injection. Second, they used 50 years as the lower age for study inclusion, and we used 65 years. Third, to control for patients who had osteoporosis before study entry, they excluded those who had a fracture in an adjacent vertebra after kyphoplasty and vertebroplasty. It is unclear if patients who had osteoporotic fractures at other sites were excluded as well. Thus, the 2 cohorts may not be directly comparable.

Whereas Mandel and colleagues¹⁴ based their definition of osteoporotic spine fracture on a keyword search of a radiology database, we used a specific reportable ICD-9-CM diagnosis code. As a result, they may have overreported osteoporotic spine fractures, and we may have underreported. Finally, our sample was much larger than theirs. Given the relative rarity of osteoporotic fractures, a study with a larger sample may have more power to detect differences. In addition, unlike Mandel and colleagues,¹⁴ we focused on an injection cohort. We did not include or make comparisons with a no-injection cohort because our study hypothesis involved the potential systemic effects of steroid injections based on injection site. Although chronic steroid use was found to have a significant effect in our study, it is unclear to what extent the diagnosis code was used, during the comorbidity assessment or only in the event of steroid-related complications.

Our study also found that, after the initial injection, each successive LJSI decreased the risk of osteoporotic wrist fracture by 10%, and each successive TSI decreased the risk of osteoporotic hip fracture by 5%. It is plausible these injections allowed improved mobility, mitigating the effects of osteoporosis induced by inactivity and lack of resistance training. It is also possible that improved mobility limited falls.

In summary, this analysis of the Medicare claims database revealed that ESI, TSI, and LJSI decreased osteoporotic spine fracture risk. However, the effect was small and may not be clinically meaningful. After the initial injection, successive ESIs had no effect on the risk of osteoporotic hip or wrist fracture, and successive LJSIs reduced the risk of osteoporotic wrist fracture, perhaps because of improved mobility. Prolonged oral steroid use increased spine fracture risk in ESI and LJSI patients. More studies are needed to evaluate the risk-benefit profile of steroid injections.

Take Home Points

• IAF is an uncommon, but serious complication of primary THA.
• Small (<50 mm) cups are at higher risk for causing IAF.
• Prompt recognition is critical to prevent component migration and need for revision.
• Posterior column integrity is cirtical to a successful outcome when IAF occurs.
• Initial stable fixation, with or without intraoperative acetabular revision, is critical for successful outcome when IAF is identified.

Intraoperative acetabular fracture (IAF) is a rare complication of primary total hip arthroplasty (THA).^1-3 IAFs commonly occur with impaction of the acetabular component. Studies have found that underreaming of the acetabulum and impaction of relatively large, elliptic, or monoblock components may increase the risk of IAFs.^2-5 There is a paucity of literature on risk factors, treatment strategies, and outcomes of this potentially devastating complication.

In this article, we report on the incidence of IAF in primary THA at our high-volume institution and present strategies for managing and preventing this rare fracture.

Materials and Methods

Between 1997 and 2015, more than 20 fellowship-trained arthroplasty surgeons performed 21,519 primary THAs at our institution. After obtaining Institutional Review Board approval for this study, we retrospectively searched the hospital database and identified 16 patients (16 hips) who sustained an IAF in primary THA. Mean age of the cohort (13 women, 3 men) at time of surgery was 70 years (range, 42-89 years). Of the 16 patients, 13 had a preoperative diagnosis of osteoarthritis, 2 had posttraumatic arthritis, and 1 had rheumatoid arthritis. A posterolateral approach was used with 14 patients and a modified anterolateral approach with the other 2. Surgical technique and implant selection varied among surgeons. Thirteen THAs were performed with an all-press-fit technique and 3 with a hybrid technique (uncemented acetabular component, cemented femoral component). In 9 cases, the acetabular component underwent supplemental screw fixation. Whether to use acetabular component screws or cemented femoral components was decided intraoperatively by the surgeon.

The cohort’s acetabular components were either elliptic modular or hemispheric modular. The elliptic modular component used was the Peripheral Self-Locking (PSL) implant (Stryker Howmedica Osteonics), and the hemispheric modular components used were either the Trident implant (Stryker Howmedica Osteonics) or the ZTT-II implant (DePuy Synthes). Elliptic acetabular components have a peripheral flare, in contrast to true hemispheric acetabular components. Ten elliptic modular and 6 hemispheric modular components were implanted. In all cases, the difference between the final reamer used to prepare the acetabular bed and the true largest external diameter of the impacted shell was 2 mm or less.

The cohort’s 16 femoral components consisted of 8 Secur-Fit uncemented components (Stryker Howmedica Osteonics), 3 Accolade uncemented components (Stryker Howmedica Osteonics), 3 Omnifit EON cemented components (Stryker Howmedica Osteonics), and 2 S-ROM uncemented components (DePuy Synthes).

After surgery, all patients were followed up according to individual surgeon protocol for radiographic and physical examination.

Data on IAF incidence were obtained from a hospital database and were confirmed with electronic medical record (EMR) documentation. Also obtained were IAF causes and locations recorded in operative notes. For fractures identified after surgery, location was obtained from the immediate postoperative radiograph. Fracture management (eg, supplemental screw fixation, fracture reduction and fixation, bone grafting, acetabular component revision, protected weight-bearing) was determined from EMR documentation.

Results

Sixteen patients sustained an IAF in primary THA. All IAFs occurred in cases involving cementless acetabular components. The institution’s incidence of IAF with use of cementless components was 0.0007%.

Of the 5 IAFs (31%) identified during surgery, 4 were noted during impaction of the acetabular component, and 1 was noted during reaming. Eighty percent of these IAFs occurred directly posterior, and 60% were addressed at time of index procedure secondary to acetabular component instability. The other 11 fractures (69%) were identified on standard postoperative anteroposterior pelvis radiographs obtained in the postanesthesia care unit (PACU). Details of component characteristics, fracture location, immediate treatment, and weight-bearing precautions for all 16 patients are listed in the Table.

There were additional complications. One patient sustained an intraoperative proximal femur fracture, which was addressed at the index THA with application of a cerclage wire and reinsertion of the femoral component; no further surgical intervention was required, and the femur fracture healed uneventfully. Another patient had a postoperative ileus that required nasogastric tube decompression and monitoring in the intensive care unit; the ileus resolved spontaneously. A third patient, initially treated with bone grafting and cemented cup insertion, was diagnosed with a periprosthetic joint infection 3 weeks after the index THA and was treated with explantation of all components and girdlestone resection arthroplasty; 1 month after the resection arthroplasty, a persistently draining wound was treated with irrigation and débridement. There were no other medical complications, thromboembolic events, or dislocations.

One to 7 weeks after surgery, patients returned for initial follow-up, and radiographs were obtained for component stability assessment. Three patients presented with gross acetabular instability, and revisions were performed. Standard clinical follow-up continued for all patients per individual surgeon protocol. Mean follow-up was 4 years.

Discussion

IAF is an uncommon complication of THA. The rarity of IAFs makes it difficult to obtain a cohort large enough to study the problem. Given the increasing incidence of primary THAs and the almost ubiquitous use of press-fit acetabular components, surgeons who perform THAs undoubtedly will encounter IAFs in their own practice. In this article, we report our institution’s experience with periprosthetic IAFs and provide a framework for making decisions regarding these complications.

Anatomical locations of IAFs have been associated with variable outcomes. In a 2015 series, Laflamme and colleagues⁶ found posterior column stability a crucial factor in implant stability. Fractures with posterior column instability had a 67% failure rate, and patients with an intact posterior column reliably had osteointegration occur without further intervention.⁶ In our series, fractures that violated the posterior column had similar results. All these fractures required further operative intervention, either at the index procedure or in the early postoperative period. Loss of posterior column stability prevents secure fixation of the acetabular component, thereby preventing successful hip reconstruction. One posterior column fracture in our series was not recognized until after surgery, on a PACU radiograph, and 1 posterior column fracture was fully appreciated only after postoperative computed tomography (CT) was obtained during immediate hospitalization after the index procedure. In both cases, conservative management was unsuccessful. Revision arthroplasty (and in 1 case late posterior column fixation) was performed to achieve adequate reconstruction. There were no failures after posterior column fixation. In cases of posterior wall or column fracture, we recommend early aggressive treatment, preferably at the time of index arthroplasty, to prevent catastrophic failure.

Most commonly, periprosthetic IAFs go unnoticed until initial postoperative radiographs are examined.⁶ Eleven of the 16 IAFs in our series were first recognized on radiographs obtained in the PACU. Surgeons thus have difficult decisions to make. The literature has little discussion on managing early postoperative periprosthetic IAFs. Most recent studies, which consist of small series and case reports, have focused on late and often traumatic IAFs.^7-9 These were initially classified by Peterson and Lewallen¹⁰ as type I, which are stable radiographically (no movement relative to previous radiographs) and do not produce pain with minor movement of the extremity, or type II, which are unstable radiographically (gross displacement of component) or produce pain with any hip motion. Type I fractures were more common and were often managed with protected weight-bearing and observation. The authors concluded that, in type I fractures, retaining the original acetabular component is difficult; however, when these fractures are treated appropriately, a functional prosthesis can be salvaged, and fracture union can be expected.

Less common are acetabular fractures detected during surgery, as in our study. In an outcome series, Haidukewych and colleagues³ reported on 21 periprosthetic acetabular fractures, all recognized during surgery and managed according to perceived stability of the component. All fractures healed uneventfully, and there were no other complications.

These studies provide a framework for addressing IAFs noticed in the early postoperative period. The diagnostic dilemma presented by these fractures was first discussed by Laflamme and colleagues.⁶ Nine of the 32 fractures in their series were classified as so-called type III fractures, recognized only after the early postoperative period. Additional radiographs (eg, Judet views) or CT scans were crucial in determining acetabular component stability, given the known poor outcomes associated with posterior column fracture. In our series, only 1 patient had CT performed after intraoperative recognition of fracture, and the extent of the fracture was not readily apparent on the patient’s postoperative radiograph. Given the successful recognition and treatment of these fractures in the early postoperative period in our series,

it is difficult to recommend advanced imaging for all periprosthetic IAFs. Perhaps this success is attributable to our almost universal use of screws for acetabular component fixation. Of the 11 patients with fractures recognized during the postoperative period, 8 had supplemental screw fixation at time of index surgery. If there is a question of fixation during component insertion, we recommend scrutinizing the acetabular rim for fracture and placing supplemental screw fixation. Screws placed for acetabular component fixation provide initial stability and may prevent early component failure in the setting of unrecognized medial or anterior fracture. In addition, when component stability is in question after impaction, we recommend using finger palpation to evaluate the sciatic notch for cortical step-off from an otherwise unrecognized fracture. Protected weight-bearing in the postoperative period may be left to the discretion of the surgeon, and the decision should be based on intraoperative stability of the acetabular component.

In our series, there was a disproportionate representation of fractures associated with elliptic acetabular components. All 5 of the fractures recognized during surgery and 5 of the 11 recognized after surgery occurred with elliptic components. The association between elliptic cup design and periprosthetic IAF was identified earlier, by Haidukewych and colleagues.³ Their series showed a statistically significant increase in fracture incidence with impaction of an elliptic cup into a bed prepared with a hemispheric reamer. In the present series, 75% of our acetabular components were impacted into a bed underreamed by 1 mm to 2 mm. It is typical of many surgeons at our institution to underream by 1 mm to 2 mm regardless of the type of component being implanted, though they show a growing trend to overream by only 1 mm with the PSL component, which has been both safe and reliable in preventing catastrophic posterior column fractures, especially with impaction of small (<50 mm) acetabular components. We have not observed early loosening or other evidence of failure with this technique. Cup impaction generates significant hoop stresses that can easily fracture sclerotic or otherwise poor-quality bone, and the dense bone around the acetabular rim experiences increased stress with impaction of elliptic components.^2,11-15 Surgeons must understand the design traits of their components and be cognizant of the true difference between the diameter of the final reamer used and the real diameter of the acetabular component. We recommend having a difference of ≤1 mm to mitigate the risk of IAF occurring with cup insertion. With use of elliptic components, slight overreaming of the acetabular bed should be considered. More study is needed to better define these outcomes.

Study Limitations

Our study had several limitations, including the inherent biases of its retrospective design, small cohort size, and inclusion of multiple surgeons. Small cohort size is unavoidable given the low incidence of these injuries, and our study encompassed the experience of a high-volume hip arthroplasty service. There is the possibility that a subset of fractures may have persistently gone unrecognized, either during or after surgery, and the actual incidence of these complications may be higher. These outcomes represent our institutional experience addressing the complexities of these injuries. The lack of standardization in the management of these fractures in our series reflects the diagnostic dilemma they present, as well as the need for more study focused on their management and outcomes.

Conclusion

IAF, an uncommon complication of primary THA, most commonly occurs during component impaction. Acetabular component and surgical technique may influence the fracture rate. Intraoperative or prompt postoperative recognition of these fractures is crucial, as their location is associated with stability and outcome. Careful examination of postoperative radiographs, judicious use of advanced imaging, and close follow-up are needed to prevent early catastrophic failure. We argue against simply observing these unstable fractures and recommend early treatment with rigid fixation and, when necessary, acetabular component revision.

Take Home Points

• IAF is an uncommon, but serious complication of primary THA.
• Small (<50 mm) cups are at higher risk for causing IAF.
• Prompt recognition is critical to prevent component migration and need for revision.
• Posterior column integrity is cirtical to a successful outcome when IAF occurs.
• Initial stable fixation, with or without intraoperative acetabular revision, is critical for successful outcome when IAF is identified.

Intraoperative acetabular fracture (IAF) is a rare complication of primary total hip arthroplasty (THA).^1-3 IAFs commonly occur with impaction of the acetabular component. Studies have found that underreaming of the acetabulum and impaction of relatively large, elliptic, or monoblock components may increase the risk of IAFs.^2-5 There is a paucity of literature on risk factors, treatment strategies, and outcomes of this potentially devastating complication.

In this article, we report on the incidence of IAF in primary THA at our high-volume institution and present strategies for managing and preventing this rare fracture.

Materials and Methods

Between 1997 and 2015, more than 20 fellowship-trained arthroplasty surgeons performed 21,519 primary THAs at our institution. After obtaining Institutional Review Board approval for this study, we retrospectively searched the hospital database and identified 16 patients (16 hips) who sustained an IAF in primary THA. Mean age of the cohort (13 women, 3 men) at time of surgery was 70 years (range, 42-89 years). Of the 16 patients, 13 had a preoperative diagnosis of osteoarthritis, 2 had posttraumatic arthritis, and 1 had rheumatoid arthritis. A posterolateral approach was used with 14 patients and a modified anterolateral approach with the other 2. Surgical technique and implant selection varied among surgeons. Thirteen THAs were performed with an all-press-fit technique and 3 with a hybrid technique (uncemented acetabular component, cemented femoral component). In 9 cases, the acetabular component underwent supplemental screw fixation. Whether to use acetabular component screws or cemented femoral components was decided intraoperatively by the surgeon.

The cohort’s acetabular components were either elliptic modular or hemispheric modular. The elliptic modular component used was the Peripheral Self-Locking (PSL) implant (Stryker Howmedica Osteonics), and the hemispheric modular components used were either the Trident implant (Stryker Howmedica Osteonics) or the ZTT-II implant (DePuy Synthes). Elliptic acetabular components have a peripheral flare, in contrast to true hemispheric acetabular components. Ten elliptic modular and 6 hemispheric modular components were implanted. In all cases, the difference between the final reamer used to prepare the acetabular bed and the true largest external diameter of the impacted shell was 2 mm or less.

The cohort’s 16 femoral components consisted of 8 Secur-Fit uncemented components (Stryker Howmedica Osteonics), 3 Accolade uncemented components (Stryker Howmedica Osteonics), 3 Omnifit EON cemented components (Stryker Howmedica Osteonics), and 2 S-ROM uncemented components (DePuy Synthes).

After surgery, all patients were followed up according to individual surgeon protocol for radiographic and physical examination.

Data on IAF incidence were obtained from a hospital database and were confirmed with electronic medical record (EMR) documentation. Also obtained were IAF causes and locations recorded in operative notes. For fractures identified after surgery, location was obtained from the immediate postoperative radiograph. Fracture management (eg, supplemental screw fixation, fracture reduction and fixation, bone grafting, acetabular component revision, protected weight-bearing) was determined from EMR documentation.

Results

Sixteen patients sustained an IAF in primary THA. All IAFs occurred in cases involving cementless acetabular components. The institution’s incidence of IAF with use of cementless components was 0.0007%.

Of the 5 IAFs (31%) identified during surgery, 4 were noted during impaction of the acetabular component, and 1 was noted during reaming. Eighty percent of these IAFs occurred directly posterior, and 60% were addressed at time of index procedure secondary to acetabular component instability. The other 11 fractures (69%) were identified on standard postoperative anteroposterior pelvis radiographs obtained in the postanesthesia care unit (PACU). Details of component characteristics, fracture location, immediate treatment, and weight-bearing precautions for all 16 patients are listed in the Table.

There were additional complications. One patient sustained an intraoperative proximal femur fracture, which was addressed at the index THA with application of a cerclage wire and reinsertion of the femoral component; no further surgical intervention was required, and the femur fracture healed uneventfully. Another patient had a postoperative ileus that required nasogastric tube decompression and monitoring in the intensive care unit; the ileus resolved spontaneously. A third patient, initially treated with bone grafting and cemented cup insertion, was diagnosed with a periprosthetic joint infection 3 weeks after the index THA and was treated with explantation of all components and girdlestone resection arthroplasty; 1 month after the resection arthroplasty, a persistently draining wound was treated with irrigation and débridement. There were no other medical complications, thromboembolic events, or dislocations.

One to 7 weeks after surgery, patients returned for initial follow-up, and radiographs were obtained for component stability assessment. Three patients presented with gross acetabular instability, and revisions were performed. Standard clinical follow-up continued for all patients per individual surgeon protocol. Mean follow-up was 4 years.

Discussion

IAF is an uncommon complication of THA. The rarity of IAFs makes it difficult to obtain a cohort large enough to study the problem. Given the increasing incidence of primary THAs and the almost ubiquitous use of press-fit acetabular components, surgeons who perform THAs undoubtedly will encounter IAFs in their own practice. In this article, we report our institution’s experience with periprosthetic IAFs and provide a framework for making decisions regarding these complications.

Anatomical locations of IAFs have been associated with variable outcomes. In a 2015 series, Laflamme and colleagues⁶ found posterior column stability a crucial factor in implant stability. Fractures with posterior column instability had a 67% failure rate, and patients with an intact posterior column reliably had osteointegration occur without further intervention.⁶ In our series, fractures that violated the posterior column had similar results. All these fractures required further operative intervention, either at the index procedure or in the early postoperative period. Loss of posterior column stability prevents secure fixation of the acetabular component, thereby preventing successful hip reconstruction. One posterior column fracture in our series was not recognized until after surgery, on a PACU radiograph, and 1 posterior column fracture was fully appreciated only after postoperative computed tomography (CT) was obtained during immediate hospitalization after the index procedure. In both cases, conservative management was unsuccessful. Revision arthroplasty (and in 1 case late posterior column fixation) was performed to achieve adequate reconstruction. There were no failures after posterior column fixation. In cases of posterior wall or column fracture, we recommend early aggressive treatment, preferably at the time of index arthroplasty, to prevent catastrophic failure.

Most commonly, periprosthetic IAFs go unnoticed until initial postoperative radiographs are examined.⁶ Eleven of the 16 IAFs in our series were first recognized on radiographs obtained in the PACU. Surgeons thus have difficult decisions to make. The literature has little discussion on managing early postoperative periprosthetic IAFs. Most recent studies, which consist of small series and case reports, have focused on late and often traumatic IAFs.^7-9 These were initially classified by Peterson and Lewallen¹⁰ as type I, which are stable radiographically (no movement relative to previous radiographs) and do not produce pain with minor movement of the extremity, or type II, which are unstable radiographically (gross displacement of component) or produce pain with any hip motion. Type I fractures were more common and were often managed with protected weight-bearing and observation. The authors concluded that, in type I fractures, retaining the original acetabular component is difficult; however, when these fractures are treated appropriately, a functional prosthesis can be salvaged, and fracture union can be expected.

Less common are acetabular fractures detected during surgery, as in our study. In an outcome series, Haidukewych and colleagues³ reported on 21 periprosthetic acetabular fractures, all recognized during surgery and managed according to perceived stability of the component. All fractures healed uneventfully, and there were no other complications.

These studies provide a framework for addressing IAFs noticed in the early postoperative period. The diagnostic dilemma presented by these fractures was first discussed by Laflamme and colleagues.⁶ Nine of the 32 fractures in their series were classified as so-called type III fractures, recognized only after the early postoperative period. Additional radiographs (eg, Judet views) or CT scans were crucial in determining acetabular component stability, given the known poor outcomes associated with posterior column fracture. In our series, only 1 patient had CT performed after intraoperative recognition of fracture, and the extent of the fracture was not readily apparent on the patient’s postoperative radiograph. Given the successful recognition and treatment of these fractures in the early postoperative period in our series,

it is difficult to recommend advanced imaging for all periprosthetic IAFs. Perhaps this success is attributable to our almost universal use of screws for acetabular component fixation. Of the 11 patients with fractures recognized during the postoperative period, 8 had supplemental screw fixation at time of index surgery. If there is a question of fixation during component insertion, we recommend scrutinizing the acetabular rim for fracture and placing supplemental screw fixation. Screws placed for acetabular component fixation provide initial stability and may prevent early component failure in the setting of unrecognized medial or anterior fracture. In addition, when component stability is in question after impaction, we recommend using finger palpation to evaluate the sciatic notch for cortical step-off from an otherwise unrecognized fracture. Protected weight-bearing in the postoperative period may be left to the discretion of the surgeon, and the decision should be based on intraoperative stability of the acetabular component.

In our series, there was a disproportionate representation of fractures associated with elliptic acetabular components. All 5 of the fractures recognized during surgery and 5 of the 11 recognized after surgery occurred with elliptic components. The association between elliptic cup design and periprosthetic IAF was identified earlier, by Haidukewych and colleagues.³ Their series showed a statistically significant increase in fracture incidence with impaction of an elliptic cup into a bed prepared with a hemispheric reamer. In the present series, 75% of our acetabular components were impacted into a bed underreamed by 1 mm to 2 mm. It is typical of many surgeons at our institution to underream by 1 mm to 2 mm regardless of the type of component being implanted, though they show a growing trend to overream by only 1 mm with the PSL component, which has been both safe and reliable in preventing catastrophic posterior column fractures, especially with impaction of small (<50 mm) acetabular components. We have not observed early loosening or other evidence of failure with this technique. Cup impaction generates significant hoop stresses that can easily fracture sclerotic or otherwise poor-quality bone, and the dense bone around the acetabular rim experiences increased stress with impaction of elliptic components.^2,11-15 Surgeons must understand the design traits of their components and be cognizant of the true difference between the diameter of the final reamer used and the real diameter of the acetabular component. We recommend having a difference of ≤1 mm to mitigate the risk of IAF occurring with cup insertion. With use of elliptic components, slight overreaming of the acetabular bed should be considered. More study is needed to better define these outcomes.

Study Limitations

Our study had several limitations, including the inherent biases of its retrospective design, small cohort size, and inclusion of multiple surgeons. Small cohort size is unavoidable given the low incidence of these injuries, and our study encompassed the experience of a high-volume hip arthroplasty service. There is the possibility that a subset of fractures may have persistently gone unrecognized, either during or after surgery, and the actual incidence of these complications may be higher. These outcomes represent our institutional experience addressing the complexities of these injuries. The lack of standardization in the management of these fractures in our series reflects the diagnostic dilemma they present, as well as the need for more study focused on their management and outcomes.

Conclusion

IAF, an uncommon complication of primary THA, most commonly occurs during component impaction. Acetabular component and surgical technique may influence the fracture rate. Intraoperative or prompt postoperative recognition of these fractures is crucial, as their location is associated with stability and outcome. Careful examination of postoperative radiographs, judicious use of advanced imaging, and close follow-up are needed to prevent early catastrophic failure. We argue against simply observing these unstable fractures and recommend early treatment with rigid fixation and, when necessary, acetabular component revision.

Take Home Points

• IAF is an uncommon, but serious complication of primary THA.
• Small (<50 mm) cups are at higher risk for causing IAF.
• Prompt recognition is critical to prevent component migration and need for revision.
• Posterior column integrity is cirtical to a successful outcome when IAF occurs.
• Initial stable fixation, with or without intraoperative acetabular revision, is critical for successful outcome when IAF is identified.

Intraoperative acetabular fracture (IAF) is a rare complication of primary total hip arthroplasty (THA).^1-3 IAFs commonly occur with impaction of the acetabular component. Studies have found that underreaming of the acetabulum and impaction of relatively large, elliptic, or monoblock components may increase the risk of IAFs.^2-5 There is a paucity of literature on risk factors, treatment strategies, and outcomes of this potentially devastating complication.

In this article, we report on the incidence of IAF in primary THA at our high-volume institution and present strategies for managing and preventing this rare fracture.

Materials and Methods

Between 1997 and 2015, more than 20 fellowship-trained arthroplasty surgeons performed 21,519 primary THAs at our institution. After obtaining Institutional Review Board approval for this study, we retrospectively searched the hospital database and identified 16 patients (16 hips) who sustained an IAF in primary THA. Mean age of the cohort (13 women, 3 men) at time of surgery was 70 years (range, 42-89 years). Of the 16 patients, 13 had a preoperative diagnosis of osteoarthritis, 2 had posttraumatic arthritis, and 1 had rheumatoid arthritis. A posterolateral approach was used with 14 patients and a modified anterolateral approach with the other 2. Surgical technique and implant selection varied among surgeons. Thirteen THAs were performed with an all-press-fit technique and 3 with a hybrid technique (uncemented acetabular component, cemented femoral component). In 9 cases, the acetabular component underwent supplemental screw fixation. Whether to use acetabular component screws or cemented femoral components was decided intraoperatively by the surgeon.

The cohort’s acetabular components were either elliptic modular or hemispheric modular. The elliptic modular component used was the Peripheral Self-Locking (PSL) implant (Stryker Howmedica Osteonics), and the hemispheric modular components used were either the Trident implant (Stryker Howmedica Osteonics) or the ZTT-II implant (DePuy Synthes). Elliptic acetabular components have a peripheral flare, in contrast to true hemispheric acetabular components. Ten elliptic modular and 6 hemispheric modular components were implanted. In all cases, the difference between the final reamer used to prepare the acetabular bed and the true largest external diameter of the impacted shell was 2 mm or less.

The cohort’s 16 femoral components consisted of 8 Secur-Fit uncemented components (Stryker Howmedica Osteonics), 3 Accolade uncemented components (Stryker Howmedica Osteonics), 3 Omnifit EON cemented components (Stryker Howmedica Osteonics), and 2 S-ROM uncemented components (DePuy Synthes).

After surgery, all patients were followed up according to individual surgeon protocol for radiographic and physical examination.

Data on IAF incidence were obtained from a hospital database and were confirmed with electronic medical record (EMR) documentation. Also obtained were IAF causes and locations recorded in operative notes. For fractures identified after surgery, location was obtained from the immediate postoperative radiograph. Fracture management (eg, supplemental screw fixation, fracture reduction and fixation, bone grafting, acetabular component revision, protected weight-bearing) was determined from EMR documentation.

Results

Sixteen patients sustained an IAF in primary THA. All IAFs occurred in cases involving cementless acetabular components. The institution’s incidence of IAF with use of cementless components was 0.0007%.

Of the 5 IAFs (31%) identified during surgery, 4 were noted during impaction of the acetabular component, and 1 was noted during reaming. Eighty percent of these IAFs occurred directly posterior, and 60% were addressed at time of index procedure secondary to acetabular component instability. The other 11 fractures (69%) were identified on standard postoperative anteroposterior pelvis radiographs obtained in the postanesthesia care unit (PACU). Details of component characteristics, fracture location, immediate treatment, and weight-bearing precautions for all 16 patients are listed in the Table.

There were additional complications. One patient sustained an intraoperative proximal femur fracture, which was addressed at the index THA with application of a cerclage wire and reinsertion of the femoral component; no further surgical intervention was required, and the femur fracture healed uneventfully. Another patient had a postoperative ileus that required nasogastric tube decompression and monitoring in the intensive care unit; the ileus resolved spontaneously. A third patient, initially treated with bone grafting and cemented cup insertion, was diagnosed with a periprosthetic joint infection 3 weeks after the index THA and was treated with explantation of all components and girdlestone resection arthroplasty; 1 month after the resection arthroplasty, a persistently draining wound was treated with irrigation and débridement. There were no other medical complications, thromboembolic events, or dislocations.

One to 7 weeks after surgery, patients returned for initial follow-up, and radiographs were obtained for component stability assessment. Three patients presented with gross acetabular instability, and revisions were performed. Standard clinical follow-up continued for all patients per individual surgeon protocol. Mean follow-up was 4 years.

Discussion

IAF is an uncommon complication of THA. The rarity of IAFs makes it difficult to obtain a cohort large enough to study the problem. Given the increasing incidence of primary THAs and the almost ubiquitous use of press-fit acetabular components, surgeons who perform THAs undoubtedly will encounter IAFs in their own practice. In this article, we report our institution’s experience with periprosthetic IAFs and provide a framework for making decisions regarding these complications.

Anatomical locations of IAFs have been associated with variable outcomes. In a 2015 series, Laflamme and colleagues⁶ found posterior column stability a crucial factor in implant stability. Fractures with posterior column instability had a 67% failure rate, and patients with an intact posterior column reliably had osteointegration occur without further intervention.⁶ In our series, fractures that violated the posterior column had similar results. All these fractures required further operative intervention, either at the index procedure or in the early postoperative period. Loss of posterior column stability prevents secure fixation of the acetabular component, thereby preventing successful hip reconstruction. One posterior column fracture in our series was not recognized until after surgery, on a PACU radiograph, and 1 posterior column fracture was fully appreciated only after postoperative computed tomography (CT) was obtained during immediate hospitalization after the index procedure. In both cases, conservative management was unsuccessful. Revision arthroplasty (and in 1 case late posterior column fixation) was performed to achieve adequate reconstruction. There were no failures after posterior column fixation. In cases of posterior wall or column fracture, we recommend early aggressive treatment, preferably at the time of index arthroplasty, to prevent catastrophic failure.

Most commonly, periprosthetic IAFs go unnoticed until initial postoperative radiographs are examined.⁶ Eleven of the 16 IAFs in our series were first recognized on radiographs obtained in the PACU. Surgeons thus have difficult decisions to make. The literature has little discussion on managing early postoperative periprosthetic IAFs. Most recent studies, which consist of small series and case reports, have focused on late and often traumatic IAFs.^7-9 These were initially classified by Peterson and Lewallen¹⁰ as type I, which are stable radiographically (no movement relative to previous radiographs) and do not produce pain with minor movement of the extremity, or type II, which are unstable radiographically (gross displacement of component) or produce pain with any hip motion. Type I fractures were more common and were often managed with protected weight-bearing and observation. The authors concluded that, in type I fractures, retaining the original acetabular component is difficult; however, when these fractures are treated appropriately, a functional prosthesis can be salvaged, and fracture union can be expected.

Less common are acetabular fractures detected during surgery, as in our study. In an outcome series, Haidukewych and colleagues³ reported on 21 periprosthetic acetabular fractures, all recognized during surgery and managed according to perceived stability of the component. All fractures healed uneventfully, and there were no other complications.

These studies provide a framework for addressing IAFs noticed in the early postoperative period. The diagnostic dilemma presented by these fractures was first discussed by Laflamme and colleagues.⁶ Nine of the 32 fractures in their series were classified as so-called type III fractures, recognized only after the early postoperative period. Additional radiographs (eg, Judet views) or CT scans were crucial in determining acetabular component stability, given the known poor outcomes associated with posterior column fracture. In our series, only 1 patient had CT performed after intraoperative recognition of fracture, and the extent of the fracture was not readily apparent on the patient’s postoperative radiograph. Given the successful recognition and treatment of these fractures in the early postoperative period in our series,

it is difficult to recommend advanced imaging for all periprosthetic IAFs. Perhaps this success is attributable to our almost universal use of screws for acetabular component fixation. Of the 11 patients with fractures recognized during the postoperative period, 8 had supplemental screw fixation at time of index surgery. If there is a question of fixation during component insertion, we recommend scrutinizing the acetabular rim for fracture and placing supplemental screw fixation. Screws placed for acetabular component fixation provide initial stability and may prevent early component failure in the setting of unrecognized medial or anterior fracture. In addition, when component stability is in question after impaction, we recommend using finger palpation to evaluate the sciatic notch for cortical step-off from an otherwise unrecognized fracture. Protected weight-bearing in the postoperative period may be left to the discretion of the surgeon, and the decision should be based on intraoperative stability of the acetabular component.

In our series, there was a disproportionate representation of fractures associated with elliptic acetabular components. All 5 of the fractures recognized during surgery and 5 of the 11 recognized after surgery occurred with elliptic components. The association between elliptic cup design and periprosthetic IAF was identified earlier, by Haidukewych and colleagues.³ Their series showed a statistically significant increase in fracture incidence with impaction of an elliptic cup into a bed prepared with a hemispheric reamer. In the present series, 75% of our acetabular components were impacted into a bed underreamed by 1 mm to 2 mm. It is typical of many surgeons at our institution to underream by 1 mm to 2 mm regardless of the type of component being implanted, though they show a growing trend to overream by only 1 mm with the PSL component, which has been both safe and reliable in preventing catastrophic posterior column fractures, especially with impaction of small (<50 mm) acetabular components. We have not observed early loosening or other evidence of failure with this technique. Cup impaction generates significant hoop stresses that can easily fracture sclerotic or otherwise poor-quality bone, and the dense bone around the acetabular rim experiences increased stress with impaction of elliptic components.^2,11-15 Surgeons must understand the design traits of their components and be cognizant of the true difference between the diameter of the final reamer used and the real diameter of the acetabular component. We recommend having a difference of ≤1 mm to mitigate the risk of IAF occurring with cup insertion. With use of elliptic components, slight overreaming of the acetabular bed should be considered. More study is needed to better define these outcomes.

Study Limitations

Our study had several limitations, including the inherent biases of its retrospective design, small cohort size, and inclusion of multiple surgeons. Small cohort size is unavoidable given the low incidence of these injuries, and our study encompassed the experience of a high-volume hip arthroplasty service. There is the possibility that a subset of fractures may have persistently gone unrecognized, either during or after surgery, and the actual incidence of these complications may be higher. These outcomes represent our institutional experience addressing the complexities of these injuries. The lack of standardization in the management of these fractures in our series reflects the diagnostic dilemma they present, as well as the need for more study focused on their management and outcomes.

Conclusion

IAF, an uncommon complication of primary THA, most commonly occurs during component impaction. Acetabular component and surgical technique may influence the fracture rate. Intraoperative or prompt postoperative recognition of these fractures is crucial, as their location is associated with stability and outcome. Careful examination of postoperative radiographs, judicious use of advanced imaging, and close follow-up are needed to prevent early catastrophic failure. We argue against simply observing these unstable fractures and recommend early treatment with rigid fixation and, when necessary, acetabular component revision.

MADRID – The rates of both total hip and total knee replacement surgeries dropped among Danish patients with rheumatoid arthritis since the mid-1990s, reductions that were coincident with more widespread use of biologic drugs as well as with other improvements in care, according to analyses of Danish national health records.

“The introduction of guidelines [on biologic drug use] in 2002 and increasing use of biologic drugs [as a result] may have contributed to this positive development,” Lene Dreyer, MD, said at the European Congress of Rheumatology. Other factors that may have also contributed include widespread use of conventional disease-modifying antirheumatic drugs (DMARDs) and adoption of a treat-to-target strategy by many clinicians.

In 1996, the first year studied and before any biologic DMARDs were routinely used for rheumatoid arthritis, the rate of total knee replacement was nearly 6/1,000 person-years among RA patients, compared with a 0.42/1,000 person-years rate in the general adult Danish population, a roughly 14-fold excess among the RA patients, Dr. Dreyer reported. But by 2016, ”this gap had almost disappeared,” she said in a video interview. “It seems like rheumatologists in Denmark are doing a good job” treating RA patients.

That may have been especially true subsequent to 2002, when the Danish Institute for Rational Pharmacotherapy issued recommendations that opened the door to wider use of biologic DMARDs, such as tumor necrosis factor inhibitors, to treat RA patients, noted Dr. Dreyer of Gentofte University Hospital, Copenhagen. During 2003-2011, use of total knee replacement surgery in RA patients fell by an average annualized rate of 0.2 surgeries/1,000 person-years. But among the general Danish population the average annualized rate of knee surgeries rose by 0.08/1,000 person-years.

“This is a very important finding,” commented Robert Landewé, MD, PhD, professor of rheumatology at the Academic Medical Center in Amsterdam. “It is extremely difficult to test the effect of the introduction of the [biologic DMARD] guidelines,” he cautioned. But he highlighted the positive finding that the excess of hip and knee replacement surgeries in patients with RA, compared with the general population, had recently narrowed.

Dr. Dreyer and her associates used records from the Danish National Patient Register to compare 29,427 patients with incident RA during 1996-2011 with more than 290,000 matched control individuals. All people studied had not undergone knee or hip replacement surgery prior to their entry into the study. The researchers used an “interrupted time series analysis” to examine the possible impact of the introduction of widespread access to biologic DMARDs starting in 2003.

The analysis showed that the rate of total hip replacements in 1996 was nearly 9 surgeries/1,000 person-years among RA patients and nearly 3/1,000 person-years in the general population, a threefold excess for RA patients. This rate fell by an average annual rate of 0.38/1,000 person-years among RA patients both before and after 2002, so that by 2011 the rate was roughly half the 1996 rate, about 4.5/1,000 patient-years. The rate in the general population rose during 1996-2011, and by 2011 was nearly 4/1,000 person-years and so nearly the same as RA patients. Wider availability of biologic DMARDs for RA patients starting in 2003 did not have an apparent impact on the rate of total hip replacement.

In contrast, wider use of biologic DMARDs appeared to have an effect on the rate of total knee surgeries among RA patients. During 1996-2001, the rate rose by an annual average of 0.19/1,000 person-years, very similar to the 0.21/1,000 person-years annual rise in the general Danish population. However, during 2003-2011, the average annual rate of total knee surgery fell by 0.20/1,000 person-years in the RA patients but continued to rise at an annual average rate of 0.08/1,000 person-years in the general population, Dr. Dreyer reported.

Additional Danish registry data exist for patients who received biologic DMARDs, and Dr. Dreyer said that she and her associates hope to use this to further examine the impact of these drugs on patient outcomes.

Dr. Dreyer has received lecture fees from Merck Sharp & Dohme and UCB. Dr. Landewé has received consulting fees from several drug companies.

mzoler@frontlinemedcom.com

On Twitter @mitchelzoler

MADRID – The rates of both total hip and total knee replacement surgeries dropped among Danish patients with rheumatoid arthritis since the mid-1990s, reductions that were coincident with more widespread use of biologic drugs as well as with other improvements in care, according to analyses of Danish national health records.

“The introduction of guidelines [on biologic drug use] in 2002 and increasing use of biologic drugs [as a result] may have contributed to this positive development,” Lene Dreyer, MD, said at the European Congress of Rheumatology. Other factors that may have also contributed include widespread use of conventional disease-modifying antirheumatic drugs (DMARDs) and adoption of a treat-to-target strategy by many clinicians.

In 1996, the first year studied and before any biologic DMARDs were routinely used for rheumatoid arthritis, the rate of total knee replacement was nearly 6/1,000 person-years among RA patients, compared with a 0.42/1,000 person-years rate in the general adult Danish population, a roughly 14-fold excess among the RA patients, Dr. Dreyer reported. But by 2016, ”this gap had almost disappeared,” she said in a video interview. “It seems like rheumatologists in Denmark are doing a good job” treating RA patients.

That may have been especially true subsequent to 2002, when the Danish Institute for Rational Pharmacotherapy issued recommendations that opened the door to wider use of biologic DMARDs, such as tumor necrosis factor inhibitors, to treat RA patients, noted Dr. Dreyer of Gentofte University Hospital, Copenhagen. During 2003-2011, use of total knee replacement surgery in RA patients fell by an average annualized rate of 0.2 surgeries/1,000 person-years. But among the general Danish population the average annualized rate of knee surgeries rose by 0.08/1,000 person-years.

“This is a very important finding,” commented Robert Landewé, MD, PhD, professor of rheumatology at the Academic Medical Center in Amsterdam. “It is extremely difficult to test the effect of the introduction of the [biologic DMARD] guidelines,” he cautioned. But he highlighted the positive finding that the excess of hip and knee replacement surgeries in patients with RA, compared with the general population, had recently narrowed.

Dr. Dreyer and her associates used records from the Danish National Patient Register to compare 29,427 patients with incident RA during 1996-2011 with more than 290,000 matched control individuals. All people studied had not undergone knee or hip replacement surgery prior to their entry into the study. The researchers used an “interrupted time series analysis” to examine the possible impact of the introduction of widespread access to biologic DMARDs starting in 2003.

The analysis showed that the rate of total hip replacements in 1996 was nearly 9 surgeries/1,000 person-years among RA patients and nearly 3/1,000 person-years in the general population, a threefold excess for RA patients. This rate fell by an average annual rate of 0.38/1,000 person-years among RA patients both before and after 2002, so that by 2011 the rate was roughly half the 1996 rate, about 4.5/1,000 patient-years. The rate in the general population rose during 1996-2011, and by 2011 was nearly 4/1,000 person-years and so nearly the same as RA patients. Wider availability of biologic DMARDs for RA patients starting in 2003 did not have an apparent impact on the rate of total hip replacement.

In contrast, wider use of biologic DMARDs appeared to have an effect on the rate of total knee surgeries among RA patients. During 1996-2001, the rate rose by an annual average of 0.19/1,000 person-years, very similar to the 0.21/1,000 person-years annual rise in the general Danish population. However, during 2003-2011, the average annual rate of total knee surgery fell by 0.20/1,000 person-years in the RA patients but continued to rise at an annual average rate of 0.08/1,000 person-years in the general population, Dr. Dreyer reported.

Additional Danish registry data exist for patients who received biologic DMARDs, and Dr. Dreyer said that she and her associates hope to use this to further examine the impact of these drugs on patient outcomes.

Dr. Dreyer has received lecture fees from Merck Sharp & Dohme and UCB. Dr. Landewé has received consulting fees from several drug companies.

mzoler@frontlinemedcom.com

On Twitter @mitchelzoler

MADRID – The rates of both total hip and total knee replacement surgeries dropped among Danish patients with rheumatoid arthritis since the mid-1990s, reductions that were coincident with more widespread use of biologic drugs as well as with other improvements in care, according to analyses of Danish national health records.

“The introduction of guidelines [on biologic drug use] in 2002 and increasing use of biologic drugs [as a result] may have contributed to this positive development,” Lene Dreyer, MD, said at the European Congress of Rheumatology. Other factors that may have also contributed include widespread use of conventional disease-modifying antirheumatic drugs (DMARDs) and adoption of a treat-to-target strategy by many clinicians.

In 1996, the first year studied and before any biologic DMARDs were routinely used for rheumatoid arthritis, the rate of total knee replacement was nearly 6/1,000 person-years among RA patients, compared with a 0.42/1,000 person-years rate in the general adult Danish population, a roughly 14-fold excess among the RA patients, Dr. Dreyer reported. But by 2016, ”this gap had almost disappeared,” she said in a video interview. “It seems like rheumatologists in Denmark are doing a good job” treating RA patients.

That may have been especially true subsequent to 2002, when the Danish Institute for Rational Pharmacotherapy issued recommendations that opened the door to wider use of biologic DMARDs, such as tumor necrosis factor inhibitors, to treat RA patients, noted Dr. Dreyer of Gentofte University Hospital, Copenhagen. During 2003-2011, use of total knee replacement surgery in RA patients fell by an average annualized rate of 0.2 surgeries/1,000 person-years. But among the general Danish population the average annualized rate of knee surgeries rose by 0.08/1,000 person-years.

“This is a very important finding,” commented Robert Landewé, MD, PhD, professor of rheumatology at the Academic Medical Center in Amsterdam. “It is extremely difficult to test the effect of the introduction of the [biologic DMARD] guidelines,” he cautioned. But he highlighted the positive finding that the excess of hip and knee replacement surgeries in patients with RA, compared with the general population, had recently narrowed.

Dr. Dreyer and her associates used records from the Danish National Patient Register to compare 29,427 patients with incident RA during 1996-2011 with more than 290,000 matched control individuals. All people studied had not undergone knee or hip replacement surgery prior to their entry into the study. The researchers used an “interrupted time series analysis” to examine the possible impact of the introduction of widespread access to biologic DMARDs starting in 2003.

The analysis showed that the rate of total hip replacements in 1996 was nearly 9 surgeries/1,000 person-years among RA patients and nearly 3/1,000 person-years in the general population, a threefold excess for RA patients. This rate fell by an average annual rate of 0.38/1,000 person-years among RA patients both before and after 2002, so that by 2011 the rate was roughly half the 1996 rate, about 4.5/1,000 patient-years. The rate in the general population rose during 1996-2011, and by 2011 was nearly 4/1,000 person-years and so nearly the same as RA patients. Wider availability of biologic DMARDs for RA patients starting in 2003 did not have an apparent impact on the rate of total hip replacement.

In contrast, wider use of biologic DMARDs appeared to have an effect on the rate of total knee surgeries among RA patients. During 1996-2001, the rate rose by an annual average of 0.19/1,000 person-years, very similar to the 0.21/1,000 person-years annual rise in the general Danish population. However, during 2003-2011, the average annual rate of total knee surgery fell by 0.20/1,000 person-years in the RA patients but continued to rise at an annual average rate of 0.08/1,000 person-years in the general population, Dr. Dreyer reported.

Additional Danish registry data exist for patients who received biologic DMARDs, and Dr. Dreyer said that she and her associates hope to use this to further examine the impact of these drugs on patient outcomes.

Dr. Dreyer has received lecture fees from Merck Sharp & Dohme and UCB. Dr. Landewé has received consulting fees from several drug companies.

mzoler@frontlinemedcom.com

On Twitter @mitchelzoler

Take-Home Points

• The prevalence of preoperative pneumonia is 1.2% among hip fracture patients aged >65 years.
• Preoperative pneumonia is an independent risk factor for mortality and adverse events including renal failure, prolonged ventilator dependence, and prolonged altered mental status after geriatric hip fracture surgery.
• Underweight BMI (<18.5 kg/m²) was associated with higher mortality within 30 days among hip fracture patients admitted with pneumonia.
• The mortality rate normalized to that of patients without pneumonia within 2 weeks of hip fracture surgery.
• Time from admission to surgery was not associated with adverse events or mortality among hip fracture patients admitted with pneumonia.

Preoperative pneumonia remains relatively unexplored as a risk factor for adverse outcomes in geriatric hip fracture surgery. Dated studies report a 0.3% to 3.2% prevalence of “recent pneumonia” in patients presenting with hip fracture but provide neither a definition of pneumonia based on clinical criteria nor a subset analysis of outcomes in the pneumonia group.^1-3 Although active pneumonia has been identified as a preoperative optimization target in the management guidelines for geriatric hip fracture,⁴ we are unaware of any studies that have reported on differences in demographics, comorbidities, delay to surgery, or adverse outcomes between hip fracture patients with and without preoperative pneumonia.

This paucity of information on the effect of preoperative pneumonia in the hip fracture population may be related to low prevalence of preoperative pneumonia and a cadre of variable definitions, which limit identification of a cohort of patients with preoperative pneumonia large enough from which to draw meaningful results. Database studies, especially those using surgical registries rather than administrative or reimbursement data, offer particular advantages for investigation of such rare clinical entities.⁵Medical care of patients with pneumonia alone is known to be facilitated by assessments of mortality risk from clinical and laboratory data. The modified British Thoracic Society rule/CURB-65 (confusion, urea, respiratory rate, blood pressure) score is strongly predictive of mortality in hospitalized adults with pneumonia (odds ratio [OR], 4.59; 95% confidence interval [CI], 1.42-14.85; P = .011) and may guide antibiotic therapy, laboratory investigations, and the decision to intubate in a patient with pneumonia.^6-8 This score is predictive of adverse events (AEs), hospital length of stay, and use of intensive care services.^6,7,9-13 We hypothesized that preoperative clinical indicators assessed by pneumonia severity scores as well as patient demographics and baseline comorbidities may also have prognostic value for risk of AEs in a cohort of geriatric hip fracture surgery patients with preoperative pneumonia.

In this article, we first describe the prevalence of preoperative pneumonia in geriatric hip fracture surgery patients as well as demographic and operative differences between patients with and without the disease. We then ask 3 questions: Is preoperative pneumonia an independent risk factor for mortality and adverse outcomes in geriatric hip fracture surgery? Is there a postoperative interval during which the unadjusted mortality rate is higher among patients with preoperative pneumonia? In patients with preoperative pneumonia, what are the predictors of morbidity and mortality?

Methods

Yale University’s Human Investigations Committee approved this retrospective cohort study, which used the American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) database for the period 2005 to 2012. ACS-NSQIP is a prospective, multi-institutional outcomes program that collects data on preoperative comorbidities, intraoperative variables, and 30-day postoperative outcomes for patients undergoing surgical procedures in inpatient and outpatient settings.¹⁴

Unlike administrative databases, which are based on reimbursement data, ACS-NSQIP data are collected by trained surgical clinical reviewers for the purposes of quality improvement and clinical research, and data quality is ensured with routine auditing.¹⁵ The program has gained a high degree of respect as a powerful and valid data source in both general¹⁶ and orthopedic¹⁷ surgery literature. The database offers a particular advantage with respect to the study of preoperative pneumonia: Only patients with new or recently diagnosed pneumonia on antibiotic therapy who meet strict criteria for characteristic findings on chest radiography, clinical signs and symptoms of respiratory illness, and positive cultures are coded as having actively treated pneumonia at time of surgery.¹⁵

To identify hip fracture patients over the age of 65 years who underwent operative fixation of a hip fracture, we used Current Procedural Terminology (CPT) hip fracture codes, including 27235 (percutaneous screw fixation), 27236 or 27244 (plate-and-screw fixation), and 27245 (intramedullary device), as well as 27125 (hemiarthroplasty) and 27130 (arthroplasty) for patients with a postoperative International Classification of Disease, Ninth Revision (ICD-9) diagnosis code (820.x, 820.2x, or 820.8) consistent with acute hip fracture.^18,19 Procedure type, anesthesia type, and delay from admission to surgery were captured for all procedures.

Preoperative demographics included age, sex, transfer origin, functional status, and body mass index (BMI) category. Binary comorbidities were classified as preoperative anemia (hematocrit, <0.41 for men, <0.36 for women), confusion, dyspnea at rest, uremia (blood urea nitrogen, >6.8 mmol/L), history of cardiovascular disease (congestive heart failure, myocardial infarction, percutaneous coronary intervention, angina pectoris, medically treated hypertension, peripheral vascular disease, or resting claudication), chronic obstructive pulmonary disease, diabetes, renal disease (renal failure or dialysis), and cigarette use in preceding 12 months.^20,21 Although preoperative hypotension and respiratory rate are often considered in patients with pneumonia, these variables were not available from the ACS-NSQIP data.^6,22Pearson χ² test for categorical variables was used to compare baseline demographics and operative characteristics between patients with and without pneumonia, and Student t test was used to compare intervals from hospital admission to hip fracture surgery, surgery start to surgery stop, and surgery to discharge between patients with and without preoperative pneumonia.

Binary outcome measures were compared between patients with and without preoperative pneumonia. “Any AE” included any serious AE (SAE) or any minor AE. SAEs included death, acute renal failure, ventilator use >48 hours, unplanned intubation, septic shock, sepsis, return to operating room, coma >24 hours, cardiac arrest requiring cardiopulmonary resuscitation, myocardial infarction, thromboembolic event (deep vein thrombosis or pulmonary embolism), and stroke/cerebrovascular accident. Minor AEs included progressive renal insufficiency, urinary tract infection, organ/space infection, superficial surgical-site infection, deep surgical-site infection, and wound dehiscence. Other binary outcome measures included discharge destination and unplanned readmission within 30 days after hip fracture surgery.²³Poisson regression with robust error variance as described by Zou²⁴ was used to compare the rates of any, minor, and individual AEs, and any SAEs, between patients with and without pneumonia. Multivariate analysis accounted for the baseline variables in Table 1. AEs that occurred more than once in each group were included in the analyses.

Results

Of the 7128 geriatric hip fracture patients in this study, 82 (1.2%) had active pneumonia at time of surgery (Table 1). Age, BMI, preoperative uremia, history of cardiovascular disease, diabetes, renal disease, and smoking were similar between groups. In addition, there was no difference in anesthesia type or fixation procedure between the pneumonia and no-pneumonia groups. Patients with preoperative pneumonia differed significantly with respect to sex, transfer from facility, preoperative functional dependence, anemia, confusion, dyspnea at rest, and history of chronic obstructive pulmonary disease (Table 1).

Interval from admission to surgery was longer (P < .001) for geriatric hip fracture patients with preoperative pneumonia (mean, 6.8 days; 95% CI, 2.5-11.1 days) than for those without pneumonia (mean, 1.5 days; CI, 1.4-1.5 days). There was no difference (P = .124) in operative time between the pneumonia group (mean, 72.8 min; CI, 64.0-81.5 min) and the no-pneumonia group (mean, 66.1 min; CI, 61.2-67.0 min). Interval from surgery to discharge was longer (P < .001) for patients with preoperative pneumonia (mean, 10.1 days; CI, 6.9-13.4 days) than for those without pneumonia (mean, 6.3 days; CI, 6.1-6.4 days).

Adverse outcomes of geriatric hip fracture surgery are listed in Table 2. In the multivariate analysis, preoperative pneumonia was significantly associated with any AE (relative risk [RR]) = 1.44) and any SAE (RR = 1.79).

Discussion

In the general US population, pneumonia accounts for 1.4% of deaths in people 65 years to 74 years old, 2.1% in people 75 years to 84 years, and 3.1% in people 85 years or older. In total, 3.4% of hospital inpatient deaths are attributed to pneumonia.²⁵ In hospitalized general orthopedic surgical patients as well as hip fracture patients, pneumonia is strongly associated with increased mortality.^26,27

We identified a preoperative pneumonia prevalence of 1.2%, which is comparable to the rates reported in the literature (0.3%-3.2%).^1-3 To our knowledge, our study represents the largest series of patients with preoperative pneumonia at time of hip fracture repair, and the first to independently associate preoperative pneumonia with increased incidence of AEs, including death.

This study had its limitations. First, the ACS-NSQIP morbidity and mortality data, which are limited to the first 30 postoperative days, may be skewed because AEs that occurred after that interval are not captured. Second, coding of pneumonia in ACS-NSQIP does not convey specific information about the disease and its severity—infectious organism(s) responsible; acquisition setting (healthcare or community); treatment given, including antibiotic(s) selection, steroid use, dosing, and duration; and measures of treatment efficacy—limiting interpretation of the difference in delay to surgery. We cannot say whether the longer interval in patients with pneumonia reflects medical optimization, or whether the delay itself or any interventions during that time positively or negatively affected outcomes. In addition, despite using a large national database, we obtained a relatively small sample of patients (82) who had pneumonia before surgical hip fracture repair.

Multivariate analysis controlling for baseline demographics and comorbidities revealed that multiple SAEs were independently associated with preoperative pneumonia (overall SAE, RR = 1.79). Postoperative use of ventilator support for longer than 48 hours (RR = 6.48) and coma longer than 24 hours (RR = 7.31) are expected given the severity of pulmonary compromise in the study cohort.^28,29 Acute renal failure (RR = 14.61) can occur in both hip fracture patients and community-acquired pneumonia patients and may be a multifactorial complication of the pulmonary infection, of the anesthesia, or of the surgical intervention in this cohort.^30-32Unadjusted mortality in hip fracture takes months to a year to normalize to that of age-matched controls.^32-34 In our series, the unadjusted death rate in the pneumonia cohort (Figure) was transiently elevated during the first weeks after surgery but then drew nearer the rate in the nondiseased hip fracture cohort by the end of the first month. Early death in the pneumonia group likely was multifactorial, potentially influenced by the increased burden of comorbidities in the pneumonia group at baseline, and the longer delay to surgery,^35-38 as well as by the natural history of treated pneumonia in hospital patients, who, compared with age-matched hospitalized controls, also exhibit higher mortality during only the first 2 to 4 months of hospitalization for pneumonia.³⁹ We regret that quality improvement strategies in the treatment of geriatric hip fracture surgery with pneumonia cannot be extrapolated from these results.

Similarly, the utility of BMI <18.5 kg/m² as an actionable preoperative finding cannot be assessed from these results. However, we propose that underweight geriatric hip fracture patients with pneumonia may benefit from more aggressive preoperative optimization that does not delay surgery. Higher acuity of postoperative care, including more intensive nursing care and early coordination of care with respiratory therapists and medical comanagement teams, may also be beneficial.

Anesthesia type did not differ between patients with and without preoperative pneumonia and was not associated with AEs in patients with preoperative pneumonia. Consistent with our findings, multiple studies have reported no significant differences in short-term outcomes of hip fracture repair between general and spinal anesthesia, though no other study has compared the benefits of general and spinal anesthesia for patients with preoperative pneumonia.^40-44 Although spinal anesthesia (relative to general anesthesia) has been reported to have benefits in hip and knee arthroplasty, these benefits appear not to translate to hip fracture repair.^45-50 The results of the present study suggest that general and spinal anesthesia may be equivalent in terms of risk for the geriatric hip fracture patient with preoperative pneumonia.^43,44Our attempt to evaluate the CURB-65 pneumonia severity score as a prognosticator of AEs was thwarted by the absence of required variables in the ACS-NSQIP dataset (confusion, uremia, dyspnea, and age were available; hypotension and blood pressure were not). In our analysis, we did include, individually, variables previously found to predict AEs in the medical pneumonia population (confusion, uremia, dyspnea at rest, anemia).^9-11,32 However, these clinical findings are nonspecific in hip fracture patients, who may become anemic, confused, dyspneic, or uremic from a multitude of factors related to their injury and unrelated to pneumonia, including but not limited to hemorrhage, muscle damage, renal injury, and pulmonary embolism. It is not surprising that confusion, uremia, dyspnea at rest, and anemia were not individually predictive of AEs or death within 30 days after surgery in the cohort of geriatric hip fracture patients with pneumonia.

There is no literature that argues for or against delaying hip fracture surgery in geriatric hip fracture patients with pneumonia. The surgical delay observed in this population is ostensibly related to medical optimization of the pneumonia and/or underlying comorbidities. However, we did not find a morbidity or mortality detriment or benefit in delaying surgery by 1 to 4 days in this population. Delay of surgery is a poor covariate, given extensive confounding by medical management and preoperative optimizing of comorbid conditions (reflected in our independent variable and covariates) as well as institutional and surgeon variations in policy and behavior and other unaccounted influences. Although some authors have found no difference in mortality or major AEs between hip fracture patients who had a surgical delay and those who did not,^31,51-53 other series and meta-analyses have suggested a mortality detriment in a surgical delay of more than 2 days^36,54 or 4 days⁵⁵ from admission. Given our data, we cannot recommend against immediate hip fracture repair in the subpopulation of geriatric hip fracture patients with pneumonia.

Our study findings suggest that preoperative pneumonia is a rare independent risk factor for AEs after hip fracture surgery in geriatric patients. Underweight BMI is predictive of death in geriatric hip fracture surgery patients who present with pneumonia, whereas early surgical repair appears not to be associated with adverse outcomes. Further investigation is warranted to determine if such patients benefit from specific preoperative and postoperative strategies for optimizing medical and surgical care based on these findings.

Am J Orthop. 2017;46(3):E177-E185. Copyright Frontline Medical Communications Inc. 2017. All rights reserved.

Take-Home Points

• The prevalence of preoperative pneumonia is 1.2% among hip fracture patients aged >65 years.
• Preoperative pneumonia is an independent risk factor for mortality and adverse events including renal failure, prolonged ventilator dependence, and prolonged altered mental status after geriatric hip fracture surgery.
• Underweight BMI (<18.5 kg/m²) was associated with higher mortality within 30 days among hip fracture patients admitted with pneumonia.
• The mortality rate normalized to that of patients without pneumonia within 2 weeks of hip fracture surgery.
• Time from admission to surgery was not associated with adverse events or mortality among hip fracture patients admitted with pneumonia.

Preoperative pneumonia remains relatively unexplored as a risk factor for adverse outcomes in geriatric hip fracture surgery. Dated studies report a 0.3% to 3.2% prevalence of “recent pneumonia” in patients presenting with hip fracture but provide neither a definition of pneumonia based on clinical criteria nor a subset analysis of outcomes in the pneumonia group.^1-3 Although active pneumonia has been identified as a preoperative optimization target in the management guidelines for geriatric hip fracture,⁴ we are unaware of any studies that have reported on differences in demographics, comorbidities, delay to surgery, or adverse outcomes between hip fracture patients with and without preoperative pneumonia.

This paucity of information on the effect of preoperative pneumonia in the hip fracture population may be related to low prevalence of preoperative pneumonia and a cadre of variable definitions, which limit identification of a cohort of patients with preoperative pneumonia large enough from which to draw meaningful results. Database studies, especially those using surgical registries rather than administrative or reimbursement data, offer particular advantages for investigation of such rare clinical entities.⁵Medical care of patients with pneumonia alone is known to be facilitated by assessments of mortality risk from clinical and laboratory data. The modified British Thoracic Society rule/CURB-65 (confusion, urea, respiratory rate, blood pressure) score is strongly predictive of mortality in hospitalized adults with pneumonia (odds ratio [OR], 4.59; 95% confidence interval [CI], 1.42-14.85; P = .011) and may guide antibiotic therapy, laboratory investigations, and the decision to intubate in a patient with pneumonia.^6-8 This score is predictive of adverse events (AEs), hospital length of stay, and use of intensive care services.^6,7,9-13 We hypothesized that preoperative clinical indicators assessed by pneumonia severity scores as well as patient demographics and baseline comorbidities may also have prognostic value for risk of AEs in a cohort of geriatric hip fracture surgery patients with preoperative pneumonia.

In this article, we first describe the prevalence of preoperative pneumonia in geriatric hip fracture surgery patients as well as demographic and operative differences between patients with and without the disease. We then ask 3 questions: Is preoperative pneumonia an independent risk factor for mortality and adverse outcomes in geriatric hip fracture surgery? Is there a postoperative interval during which the unadjusted mortality rate is higher among patients with preoperative pneumonia? In patients with preoperative pneumonia, what are the predictors of morbidity and mortality?

Methods

Yale University’s Human Investigations Committee approved this retrospective cohort study, which used the American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) database for the period 2005 to 2012. ACS-NSQIP is a prospective, multi-institutional outcomes program that collects data on preoperative comorbidities, intraoperative variables, and 30-day postoperative outcomes for patients undergoing surgical procedures in inpatient and outpatient settings.¹⁴

Unlike administrative databases, which are based on reimbursement data, ACS-NSQIP data are collected by trained surgical clinical reviewers for the purposes of quality improvement and clinical research, and data quality is ensured with routine auditing.¹⁵ The program has gained a high degree of respect as a powerful and valid data source in both general¹⁶ and orthopedic¹⁷ surgery literature. The database offers a particular advantage with respect to the study of preoperative pneumonia: Only patients with new or recently diagnosed pneumonia on antibiotic therapy who meet strict criteria for characteristic findings on chest radiography, clinical signs and symptoms of respiratory illness, and positive cultures are coded as having actively treated pneumonia at time of surgery.¹⁵

To identify hip fracture patients over the age of 65 years who underwent operative fixation of a hip fracture, we used Current Procedural Terminology (CPT) hip fracture codes, including 27235 (percutaneous screw fixation), 27236 or 27244 (plate-and-screw fixation), and 27245 (intramedullary device), as well as 27125 (hemiarthroplasty) and 27130 (arthroplasty) for patients with a postoperative International Classification of Disease, Ninth Revision (ICD-9) diagnosis code (820.x, 820.2x, or 820.8) consistent with acute hip fracture.^18,19 Procedure type, anesthesia type, and delay from admission to surgery were captured for all procedures.

Preoperative demographics included age, sex, transfer origin, functional status, and body mass index (BMI) category. Binary comorbidities were classified as preoperative anemia (hematocrit, <0.41 for men, <0.36 for women), confusion, dyspnea at rest, uremia (blood urea nitrogen, >6.8 mmol/L), history of cardiovascular disease (congestive heart failure, myocardial infarction, percutaneous coronary intervention, angina pectoris, medically treated hypertension, peripheral vascular disease, or resting claudication), chronic obstructive pulmonary disease, diabetes, renal disease (renal failure or dialysis), and cigarette use in preceding 12 months.^20,21 Although preoperative hypotension and respiratory rate are often considered in patients with pneumonia, these variables were not available from the ACS-NSQIP data.^6,22Pearson χ² test for categorical variables was used to compare baseline demographics and operative characteristics between patients with and without pneumonia, and Student t test was used to compare intervals from hospital admission to hip fracture surgery, surgery start to surgery stop, and surgery to discharge between patients with and without preoperative pneumonia.

Binary outcome measures were compared between patients with and without preoperative pneumonia. “Any AE” included any serious AE (SAE) or any minor AE. SAEs included death, acute renal failure, ventilator use >48 hours, unplanned intubation, septic shock, sepsis, return to operating room, coma >24 hours, cardiac arrest requiring cardiopulmonary resuscitation, myocardial infarction, thromboembolic event (deep vein thrombosis or pulmonary embolism), and stroke/cerebrovascular accident. Minor AEs included progressive renal insufficiency, urinary tract infection, organ/space infection, superficial surgical-site infection, deep surgical-site infection, and wound dehiscence. Other binary outcome measures included discharge destination and unplanned readmission within 30 days after hip fracture surgery.²³Poisson regression with robust error variance as described by Zou²⁴ was used to compare the rates of any, minor, and individual AEs, and any SAEs, between patients with and without pneumonia. Multivariate analysis accounted for the baseline variables in Table 1. AEs that occurred more than once in each group were included in the analyses.

Results

Of the 7128 geriatric hip fracture patients in this study, 82 (1.2%) had active pneumonia at time of surgery (Table 1). Age, BMI, preoperative uremia, history of cardiovascular disease, diabetes, renal disease, and smoking were similar between groups. In addition, there was no difference in anesthesia type or fixation procedure between the pneumonia and no-pneumonia groups. Patients with preoperative pneumonia differed significantly with respect to sex, transfer from facility, preoperative functional dependence, anemia, confusion, dyspnea at rest, and history of chronic obstructive pulmonary disease (Table 1).

Interval from admission to surgery was longer (P < .001) for geriatric hip fracture patients with preoperative pneumonia (mean, 6.8 days; 95% CI, 2.5-11.1 days) than for those without pneumonia (mean, 1.5 days; CI, 1.4-1.5 days). There was no difference (P = .124) in operative time between the pneumonia group (mean, 72.8 min; CI, 64.0-81.5 min) and the no-pneumonia group (mean, 66.1 min; CI, 61.2-67.0 min). Interval from surgery to discharge was longer (P < .001) for patients with preoperative pneumonia (mean, 10.1 days; CI, 6.9-13.4 days) than for those without pneumonia (mean, 6.3 days; CI, 6.1-6.4 days).

Adverse outcomes of geriatric hip fracture surgery are listed in Table 2. In the multivariate analysis, preoperative pneumonia was significantly associated with any AE (relative risk [RR]) = 1.44) and any SAE (RR = 1.79).

Discussion

In the general US population, pneumonia accounts for 1.4% of deaths in people 65 years to 74 years old, 2.1% in people 75 years to 84 years, and 3.1% in people 85 years or older. In total, 3.4% of hospital inpatient deaths are attributed to pneumonia.²⁵ In hospitalized general orthopedic surgical patients as well as hip fracture patients, pneumonia is strongly associated with increased mortality.^26,27

We identified a preoperative pneumonia prevalence of 1.2%, which is comparable to the rates reported in the literature (0.3%-3.2%).^1-3 To our knowledge, our study represents the largest series of patients with preoperative pneumonia at time of hip fracture repair, and the first to independently associate preoperative pneumonia with increased incidence of AEs, including death.

This study had its limitations. First, the ACS-NSQIP morbidity and mortality data, which are limited to the first 30 postoperative days, may be skewed because AEs that occurred after that interval are not captured. Second, coding of pneumonia in ACS-NSQIP does not convey specific information about the disease and its severity—infectious organism(s) responsible; acquisition setting (healthcare or community); treatment given, including antibiotic(s) selection, steroid use, dosing, and duration; and measures of treatment efficacy—limiting interpretation of the difference in delay to surgery. We cannot say whether the longer interval in patients with pneumonia reflects medical optimization, or whether the delay itself or any interventions during that time positively or negatively affected outcomes. In addition, despite using a large national database, we obtained a relatively small sample of patients (82) who had pneumonia before surgical hip fracture repair.

Multivariate analysis controlling for baseline demographics and comorbidities revealed that multiple SAEs were independently associated with preoperative pneumonia (overall SAE, RR = 1.79). Postoperative use of ventilator support for longer than 48 hours (RR = 6.48) and coma longer than 24 hours (RR = 7.31) are expected given the severity of pulmonary compromise in the study cohort.^28,29 Acute renal failure (RR = 14.61) can occur in both hip fracture patients and community-acquired pneumonia patients and may be a multifactorial complication of the pulmonary infection, of the anesthesia, or of the surgical intervention in this cohort.^30-32Unadjusted mortality in hip fracture takes months to a year to normalize to that of age-matched controls.^32-34 In our series, the unadjusted death rate in the pneumonia cohort (Figure) was transiently elevated during the first weeks after surgery but then drew nearer the rate in the nondiseased hip fracture cohort by the end of the first month. Early death in the pneumonia group likely was multifactorial, potentially influenced by the increased burden of comorbidities in the pneumonia group at baseline, and the longer delay to surgery,^35-38 as well as by the natural history of treated pneumonia in hospital patients, who, compared with age-matched hospitalized controls, also exhibit higher mortality during only the first 2 to 4 months of hospitalization for pneumonia.³⁹ We regret that quality improvement strategies in the treatment of geriatric hip fracture surgery with pneumonia cannot be extrapolated from these results.

Similarly, the utility of BMI <18.5 kg/m² as an actionable preoperative finding cannot be assessed from these results. However, we propose that underweight geriatric hip fracture patients with pneumonia may benefit from more aggressive preoperative optimization that does not delay surgery. Higher acuity of postoperative care, including more intensive nursing care and early coordination of care with respiratory therapists and medical comanagement teams, may also be beneficial.

Anesthesia type did not differ between patients with and without preoperative pneumonia and was not associated with AEs in patients with preoperative pneumonia. Consistent with our findings, multiple studies have reported no significant differences in short-term outcomes of hip fracture repair between general and spinal anesthesia, though no other study has compared the benefits of general and spinal anesthesia for patients with preoperative pneumonia.^40-44 Although spinal anesthesia (relative to general anesthesia) has been reported to have benefits in hip and knee arthroplasty, these benefits appear not to translate to hip fracture repair.^45-50 The results of the present study suggest that general and spinal anesthesia may be equivalent in terms of risk for the geriatric hip fracture patient with preoperative pneumonia.^43,44Our attempt to evaluate the CURB-65 pneumonia severity score as a prognosticator of AEs was thwarted by the absence of required variables in the ACS-NSQIP dataset (confusion, uremia, dyspnea, and age were available; hypotension and blood pressure were not). In our analysis, we did include, individually, variables previously found to predict AEs in the medical pneumonia population (confusion, uremia, dyspnea at rest, anemia).^9-11,32 However, these clinical findings are nonspecific in hip fracture patients, who may become anemic, confused, dyspneic, or uremic from a multitude of factors related to their injury and unrelated to pneumonia, including but not limited to hemorrhage, muscle damage, renal injury, and pulmonary embolism. It is not surprising that confusion, uremia, dyspnea at rest, and anemia were not individually predictive of AEs or death within 30 days after surgery in the cohort of geriatric hip fracture patients with pneumonia.

There is no literature that argues for or against delaying hip fracture surgery in geriatric hip fracture patients with pneumonia. The surgical delay observed in this population is ostensibly related to medical optimization of the pneumonia and/or underlying comorbidities. However, we did not find a morbidity or mortality detriment or benefit in delaying surgery by 1 to 4 days in this population. Delay of surgery is a poor covariate, given extensive confounding by medical management and preoperative optimizing of comorbid conditions (reflected in our independent variable and covariates) as well as institutional and surgeon variations in policy and behavior and other unaccounted influences. Although some authors have found no difference in mortality or major AEs between hip fracture patients who had a surgical delay and those who did not,^31,51-53 other series and meta-analyses have suggested a mortality detriment in a surgical delay of more than 2 days^36,54 or 4 days⁵⁵ from admission. Given our data, we cannot recommend against immediate hip fracture repair in the subpopulation of geriatric hip fracture patients with pneumonia.

Our study findings suggest that preoperative pneumonia is a rare independent risk factor for AEs after hip fracture surgery in geriatric patients. Underweight BMI is predictive of death in geriatric hip fracture surgery patients who present with pneumonia, whereas early surgical repair appears not to be associated with adverse outcomes. Further investigation is warranted to determine if such patients benefit from specific preoperative and postoperative strategies for optimizing medical and surgical care based on these findings.

Am J Orthop. 2017;46(3):E177-E185. Copyright Frontline Medical Communications Inc. 2017. All rights reserved.

Take-Home Points

• The prevalence of preoperative pneumonia is 1.2% among hip fracture patients aged >65 years.
• Preoperative pneumonia is an independent risk factor for mortality and adverse events including renal failure, prolonged ventilator dependence, and prolonged altered mental status after geriatric hip fracture surgery.
• Underweight BMI (<18.5 kg/m²) was associated with higher mortality within 30 days among hip fracture patients admitted with pneumonia.
• The mortality rate normalized to that of patients without pneumonia within 2 weeks of hip fracture surgery.
• Time from admission to surgery was not associated with adverse events or mortality among hip fracture patients admitted with pneumonia.

Preoperative pneumonia remains relatively unexplored as a risk factor for adverse outcomes in geriatric hip fracture surgery. Dated studies report a 0.3% to 3.2% prevalence of “recent pneumonia” in patients presenting with hip fracture but provide neither a definition of pneumonia based on clinical criteria nor a subset analysis of outcomes in the pneumonia group.^1-3 Although active pneumonia has been identified as a preoperative optimization target in the management guidelines for geriatric hip fracture,⁴ we are unaware of any studies that have reported on differences in demographics, comorbidities, delay to surgery, or adverse outcomes between hip fracture patients with and without preoperative pneumonia.

This paucity of information on the effect of preoperative pneumonia in the hip fracture population may be related to low prevalence of preoperative pneumonia and a cadre of variable definitions, which limit identification of a cohort of patients with preoperative pneumonia large enough from which to draw meaningful results. Database studies, especially those using surgical registries rather than administrative or reimbursement data, offer particular advantages for investigation of such rare clinical entities.⁵Medical care of patients with pneumonia alone is known to be facilitated by assessments of mortality risk from clinical and laboratory data. The modified British Thoracic Society rule/CURB-65 (confusion, urea, respiratory rate, blood pressure) score is strongly predictive of mortality in hospitalized adults with pneumonia (odds ratio [OR], 4.59; 95% confidence interval [CI], 1.42-14.85; P = .011) and may guide antibiotic therapy, laboratory investigations, and the decision to intubate in a patient with pneumonia.^6-8 This score is predictive of adverse events (AEs), hospital length of stay, and use of intensive care services.^6,7,9-13 We hypothesized that preoperative clinical indicators assessed by pneumonia severity scores as well as patient demographics and baseline comorbidities may also have prognostic value for risk of AEs in a cohort of geriatric hip fracture surgery patients with preoperative pneumonia.

In this article, we first describe the prevalence of preoperative pneumonia in geriatric hip fracture surgery patients as well as demographic and operative differences between patients with and without the disease. We then ask 3 questions: Is preoperative pneumonia an independent risk factor for mortality and adverse outcomes in geriatric hip fracture surgery? Is there a postoperative interval during which the unadjusted mortality rate is higher among patients with preoperative pneumonia? In patients with preoperative pneumonia, what are the predictors of morbidity and mortality?

Methods

Yale University’s Human Investigations Committee approved this retrospective cohort study, which used the American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) database for the period 2005 to 2012. ACS-NSQIP is a prospective, multi-institutional outcomes program that collects data on preoperative comorbidities, intraoperative variables, and 30-day postoperative outcomes for patients undergoing surgical procedures in inpatient and outpatient settings.¹⁴

Unlike administrative databases, which are based on reimbursement data, ACS-NSQIP data are collected by trained surgical clinical reviewers for the purposes of quality improvement and clinical research, and data quality is ensured with routine auditing.¹⁵ The program has gained a high degree of respect as a powerful and valid data source in both general¹⁶ and orthopedic¹⁷ surgery literature. The database offers a particular advantage with respect to the study of preoperative pneumonia: Only patients with new or recently diagnosed pneumonia on antibiotic therapy who meet strict criteria for characteristic findings on chest radiography, clinical signs and symptoms of respiratory illness, and positive cultures are coded as having actively treated pneumonia at time of surgery.¹⁵

To identify hip fracture patients over the age of 65 years who underwent operative fixation of a hip fracture, we used Current Procedural Terminology (CPT) hip fracture codes, including 27235 (percutaneous screw fixation), 27236 or 27244 (plate-and-screw fixation), and 27245 (intramedullary device), as well as 27125 (hemiarthroplasty) and 27130 (arthroplasty) for patients with a postoperative International Classification of Disease, Ninth Revision (ICD-9) diagnosis code (820.x, 820.2x, or 820.8) consistent with acute hip fracture.^18,19 Procedure type, anesthesia type, and delay from admission to surgery were captured for all procedures.

Preoperative demographics included age, sex, transfer origin, functional status, and body mass index (BMI) category. Binary comorbidities were classified as preoperative anemia (hematocrit, <0.41 for men, <0.36 for women), confusion, dyspnea at rest, uremia (blood urea nitrogen, >6.8 mmol/L), history of cardiovascular disease (congestive heart failure, myocardial infarction, percutaneous coronary intervention, angina pectoris, medically treated hypertension, peripheral vascular disease, or resting claudication), chronic obstructive pulmonary disease, diabetes, renal disease (renal failure or dialysis), and cigarette use in preceding 12 months.^20,21 Although preoperative hypotension and respiratory rate are often considered in patients with pneumonia, these variables were not available from the ACS-NSQIP data.^6,22Pearson χ² test for categorical variables was used to compare baseline demographics and operative characteristics between patients with and without pneumonia, and Student t test was used to compare intervals from hospital admission to hip fracture surgery, surgery start to surgery stop, and surgery to discharge between patients with and without preoperative pneumonia.

Binary outcome measures were compared between patients with and without preoperative pneumonia. “Any AE” included any serious AE (SAE) or any minor AE. SAEs included death, acute renal failure, ventilator use >48 hours, unplanned intubation, septic shock, sepsis, return to operating room, coma >24 hours, cardiac arrest requiring cardiopulmonary resuscitation, myocardial infarction, thromboembolic event (deep vein thrombosis or pulmonary embolism), and stroke/cerebrovascular accident. Minor AEs included progressive renal insufficiency, urinary tract infection, organ/space infection, superficial surgical-site infection, deep surgical-site infection, and wound dehiscence. Other binary outcome measures included discharge destination and unplanned readmission within 30 days after hip fracture surgery.²³Poisson regression with robust error variance as described by Zou²⁴ was used to compare the rates of any, minor, and individual AEs, and any SAEs, between patients with and without pneumonia. Multivariate analysis accounted for the baseline variables in Table 1. AEs that occurred more than once in each group were included in the analyses.

Results

Of the 7128 geriatric hip fracture patients in this study, 82 (1.2%) had active pneumonia at time of surgery (Table 1). Age, BMI, preoperative uremia, history of cardiovascular disease, diabetes, renal disease, and smoking were similar between groups. In addition, there was no difference in anesthesia type or fixation procedure between the pneumonia and no-pneumonia groups. Patients with preoperative pneumonia differed significantly with respect to sex, transfer from facility, preoperative functional dependence, anemia, confusion, dyspnea at rest, and history of chronic obstructive pulmonary disease (Table 1).

Interval from admission to surgery was longer (P < .001) for geriatric hip fracture patients with preoperative pneumonia (mean, 6.8 days; 95% CI, 2.5-11.1 days) than for those without pneumonia (mean, 1.5 days; CI, 1.4-1.5 days). There was no difference (P = .124) in operative time between the pneumonia group (mean, 72.8 min; CI, 64.0-81.5 min) and the no-pneumonia group (mean, 66.1 min; CI, 61.2-67.0 min). Interval from surgery to discharge was longer (P < .001) for patients with preoperative pneumonia (mean, 10.1 days; CI, 6.9-13.4 days) than for those without pneumonia (mean, 6.3 days; CI, 6.1-6.4 days).

Adverse outcomes of geriatric hip fracture surgery are listed in Table 2. In the multivariate analysis, preoperative pneumonia was significantly associated with any AE (relative risk [RR]) = 1.44) and any SAE (RR = 1.79).

Discussion

In the general US population, pneumonia accounts for 1.4% of deaths in people 65 years to 74 years old, 2.1% in people 75 years to 84 years, and 3.1% in people 85 years or older. In total, 3.4% of hospital inpatient deaths are attributed to pneumonia.²⁵ In hospitalized general orthopedic surgical patients as well as hip fracture patients, pneumonia is strongly associated with increased mortality.^26,27

We identified a preoperative pneumonia prevalence of 1.2%, which is comparable to the rates reported in the literature (0.3%-3.2%).^1-3 To our knowledge, our study represents the largest series of patients with preoperative pneumonia at time of hip fracture repair, and the first to independently associate preoperative pneumonia with increased incidence of AEs, including death.

This study had its limitations. First, the ACS-NSQIP morbidity and mortality data, which are limited to the first 30 postoperative days, may be skewed because AEs that occurred after that interval are not captured. Second, coding of pneumonia in ACS-NSQIP does not convey specific information about the disease and its severity—infectious organism(s) responsible; acquisition setting (healthcare or community); treatment given, including antibiotic(s) selection, steroid use, dosing, and duration; and measures of treatment efficacy—limiting interpretation of the difference in delay to surgery. We cannot say whether the longer interval in patients with pneumonia reflects medical optimization, or whether the delay itself or any interventions during that time positively or negatively affected outcomes. In addition, despite using a large national database, we obtained a relatively small sample of patients (82) who had pneumonia before surgical hip fracture repair.

Multivariate analysis controlling for baseline demographics and comorbidities revealed that multiple SAEs were independently associated with preoperative pneumonia (overall SAE, RR = 1.79). Postoperative use of ventilator support for longer than 48 hours (RR = 6.48) and coma longer than 24 hours (RR = 7.31) are expected given the severity of pulmonary compromise in the study cohort.^28,29 Acute renal failure (RR = 14.61) can occur in both hip fracture patients and community-acquired pneumonia patients and may be a multifactorial complication of the pulmonary infection, of the anesthesia, or of the surgical intervention in this cohort.^30-32Unadjusted mortality in hip fracture takes months to a year to normalize to that of age-matched controls.^32-34 In our series, the unadjusted death rate in the pneumonia cohort (Figure) was transiently elevated during the first weeks after surgery but then drew nearer the rate in the nondiseased hip fracture cohort by the end of the first month. Early death in the pneumonia group likely was multifactorial, potentially influenced by the increased burden of comorbidities in the pneumonia group at baseline, and the longer delay to surgery,^35-38 as well as by the natural history of treated pneumonia in hospital patients, who, compared with age-matched hospitalized controls, also exhibit higher mortality during only the first 2 to 4 months of hospitalization for pneumonia.³⁹ We regret that quality improvement strategies in the treatment of geriatric hip fracture surgery with pneumonia cannot be extrapolated from these results.

Similarly, the utility of BMI <18.5 kg/m² as an actionable preoperative finding cannot be assessed from these results. However, we propose that underweight geriatric hip fracture patients with pneumonia may benefit from more aggressive preoperative optimization that does not delay surgery. Higher acuity of postoperative care, including more intensive nursing care and early coordination of care with respiratory therapists and medical comanagement teams, may also be beneficial.

Anesthesia type did not differ between patients with and without preoperative pneumonia and was not associated with AEs in patients with preoperative pneumonia. Consistent with our findings, multiple studies have reported no significant differences in short-term outcomes of hip fracture repair between general and spinal anesthesia, though no other study has compared the benefits of general and spinal anesthesia for patients with preoperative pneumonia.^40-44 Although spinal anesthesia (relative to general anesthesia) has been reported to have benefits in hip and knee arthroplasty, these benefits appear not to translate to hip fracture repair.^45-50 The results of the present study suggest that general and spinal anesthesia may be equivalent in terms of risk for the geriatric hip fracture patient with preoperative pneumonia.^43,44Our attempt to evaluate the CURB-65 pneumonia severity score as a prognosticator of AEs was thwarted by the absence of required variables in the ACS-NSQIP dataset (confusion, uremia, dyspnea, and age were available; hypotension and blood pressure were not). In our analysis, we did include, individually, variables previously found to predict AEs in the medical pneumonia population (confusion, uremia, dyspnea at rest, anemia).^9-11,32 However, these clinical findings are nonspecific in hip fracture patients, who may become anemic, confused, dyspneic, or uremic from a multitude of factors related to their injury and unrelated to pneumonia, including but not limited to hemorrhage, muscle damage, renal injury, and pulmonary embolism. It is not surprising that confusion, uremia, dyspnea at rest, and anemia were not individually predictive of AEs or death within 30 days after surgery in the cohort of geriatric hip fracture patients with pneumonia.

There is no literature that argues for or against delaying hip fracture surgery in geriatric hip fracture patients with pneumonia. The surgical delay observed in this population is ostensibly related to medical optimization of the pneumonia and/or underlying comorbidities. However, we did not find a morbidity or mortality detriment or benefit in delaying surgery by 1 to 4 days in this population. Delay of surgery is a poor covariate, given extensive confounding by medical management and preoperative optimizing of comorbid conditions (reflected in our independent variable and covariates) as well as institutional and surgeon variations in policy and behavior and other unaccounted influences. Although some authors have found no difference in mortality or major AEs between hip fracture patients who had a surgical delay and those who did not,^31,51-53 other series and meta-analyses have suggested a mortality detriment in a surgical delay of more than 2 days^36,54 or 4 days⁵⁵ from admission. Given our data, we cannot recommend against immediate hip fracture repair in the subpopulation of geriatric hip fracture patients with pneumonia.

Our study findings suggest that preoperative pneumonia is a rare independent risk factor for AEs after hip fracture surgery in geriatric patients. Underweight BMI is predictive of death in geriatric hip fracture surgery patients who present with pneumonia, whereas early surgical repair appears not to be associated with adverse outcomes. Further investigation is warranted to determine if such patients benefit from specific preoperative and postoperative strategies for optimizing medical and surgical care based on these findings.

Am J Orthop. 2017;46(3):E177-E185. Copyright Frontline Medical Communications Inc. 2017. All rights reserved.

Take-Home Points

• AIPD of DM-THA is defined by dissociation within 1 year of implantation resulting from component impingement or closed reduction maneuvers.
• This is a distinct entity from “late” IPD (>1 year) from implantation as this is associated most often with polyethylene wear, component loosening, and arthrofibrosis.
• A history of DM dislocation followed by subjective “clunking,” instability, and a series of more frequent dislocations should raise concern for AIPD.
• Classic radiographic findings of AIPD include eccentric hip reduction and soft tissue radiolucency (ie, halo sign) from dissociated polyethylene component.

• Treating practitioners of AIPD should consider closed reduction with general anesthesia and sedation in the operating room to limit risk of dissociation.

Dual-mobility (DM) components were invented in the 1970s and have been used in primary and revision total hip arthroplasty (THA) in Europe ever since.¹ However, DM components are most commonly used in the treatment of recurrent hip instability, and early results have been promising.² In DM-THAs, a smaller (22-mm or 28-mm) metal femoral head snap-fits into a larger polyethylene ball (inner articulation), which articulates with a highly polished metal shell (outer articulation), which is either implanted directly in the acetabulum or placed in an uncemented acetabular cup. The 2 articulations used in these devices theoretically increase hip range of motion (ROM) and increase the inferior head displacement distance (jump distance) required for dislocation.³

However, this DM articulation with increased ROM may also cause chronic impingement of the femoral component neck or Morse taper against the outer polyethylene bearing, resulting in polyethylene wear and late intraprosthetic dissociation (IPD) (separation of inner articulation between femoral head and polyethylene liner). In 2004, Lecuire and colleagues⁴ reported 7 cases of IPD occurring a mean of 10 years after implantation during the period 1989 to 1997. In 2013, Philippot and colleagues⁵ reported that 81 of 1960 primary THAs developed IPD a mean of 9 years after implantation. These IPD cases were attributed to polyethylene wear or outer articulation blockage caused by arthrofibrosis or heterotopic ossification. Reports of acute IPD (AIPD), however, are rare. In 2011, Stigbrand and Ullmark⁶ reported 3 cases in which the DM prosthesis dislocated within 1 year after implantation. It was suggested that the inner metal head dissociated from the larger polyethylene component after attempted closed reduction for dislocation (separation of larger polyethylene component from acetabulum or acetabular liner).

DM components were unavailable to surgeons in the United States until 2011. The first US Food and Drug Administration (FDA)-approved DM device was the MDM (Modular Dual Mobility, Stryker). To our knowledge, 2 cases of AIPD with this prosthesis have been reported.^{7, 8} As with the cases in Europe, closed reduction was the suspected cause, but there was no explanation for the initial dislocation event.

In this article, we present the case of a nondemented man who developed AIPD of a THA with the MDM component and a 28-mm femoral head with a skirted neck (StelKast). His operative findings suggest a poor head-to-neck ratio caused by a larger diameter femoral neck or a skirted prosthesis, or a forceful reduction maneuver, may predispose DM components to AIPD. The patient provided written informed consent for print and electronic publication of this case report.

Case Report

In 2012, a 63-year-old man with a history of drug abuse underwent left primary THA. Seven posterior dislocations and 3 years later, the acetabular component was revised to the MDM prosthesis; the well-fixed StelKast femoral component was retained (Figure 1).

Within 3 months after revision surgery, the left hip dislocated 3 times in 1 week, when the patient bent over to retrieve an object on the ground. The first 2 dislocations were treated with closed reduction under conscious sedation at an outside emergency department.

Discussion

Recurrent dislocation and instability accounts for 22.5% of THA revisions in the United States.⁹ Until 2011, options for managing recurrent dislocation in the United States included modular component exchange, component revision for malposition, and use of constrained components.¹⁰

In 1974, Bousquet first reported use of the DM prosthesis in primary THA; the prosthesis allowed increased stability without sacrificing motion or fixation.¹ However, longer-term studies of DM components disclosed a new complication, IPD. In 2004, Lecuire and colleagues⁴ reported 7 cases of IPD occurring a mean of 10 years after implantation of the Bousquet prosthesis.

Take-Home Points

• AIPD of DM-THA is defined by dissociation within 1 year of implantation resulting from component impingement or closed reduction maneuvers.
• This is a distinct entity from “late” IPD (>1 year) from implantation as this is associated most often with polyethylene wear, component loosening, and arthrofibrosis.
• A history of DM dislocation followed by subjective “clunking,” instability, and a series of more frequent dislocations should raise concern for AIPD.
• Classic radiographic findings of AIPD include eccentric hip reduction and soft tissue radiolucency (ie, halo sign) from dissociated polyethylene component.

• Treating practitioners of AIPD should consider closed reduction with general anesthesia and sedation in the operating room to limit risk of dissociation.

Dual-mobility (DM) components were invented in the 1970s and have been used in primary and revision total hip arthroplasty (THA) in Europe ever since.¹ However, DM components are most commonly used in the treatment of recurrent hip instability, and early results have been promising.² In DM-THAs, a smaller (22-mm or 28-mm) metal femoral head snap-fits into a larger polyethylene ball (inner articulation), which articulates with a highly polished metal shell (outer articulation), which is either implanted directly in the acetabulum or placed in an uncemented acetabular cup. The 2 articulations used in these devices theoretically increase hip range of motion (ROM) and increase the inferior head displacement distance (jump distance) required for dislocation.³

However, this DM articulation with increased ROM may also cause chronic impingement of the femoral component neck or Morse taper against the outer polyethylene bearing, resulting in polyethylene wear and late intraprosthetic dissociation (IPD) (separation of inner articulation between femoral head and polyethylene liner). In 2004, Lecuire and colleagues⁴ reported 7 cases of IPD occurring a mean of 10 years after implantation during the period 1989 to 1997. In 2013, Philippot and colleagues⁵ reported that 81 of 1960 primary THAs developed IPD a mean of 9 years after implantation. These IPD cases were attributed to polyethylene wear or outer articulation blockage caused by arthrofibrosis or heterotopic ossification. Reports of acute IPD (AIPD), however, are rare. In 2011, Stigbrand and Ullmark⁶ reported 3 cases in which the DM prosthesis dislocated within 1 year after implantation. It was suggested that the inner metal head dissociated from the larger polyethylene component after attempted closed reduction for dislocation (separation of larger polyethylene component from acetabulum or acetabular liner).

DM components were unavailable to surgeons in the United States until 2011. The first US Food and Drug Administration (FDA)-approved DM device was the MDM (Modular Dual Mobility, Stryker). To our knowledge, 2 cases of AIPD with this prosthesis have been reported.^{7, 8} As with the cases in Europe, closed reduction was the suspected cause, but there was no explanation for the initial dislocation event.

In this article, we present the case of a nondemented man who developed AIPD of a THA with the MDM component and a 28-mm femoral head with a skirted neck (StelKast). His operative findings suggest a poor head-to-neck ratio caused by a larger diameter femoral neck or a skirted prosthesis, or a forceful reduction maneuver, may predispose DM components to AIPD. The patient provided written informed consent for print and electronic publication of this case report.

Case Report

In 2012, a 63-year-old man with a history of drug abuse underwent left primary THA. Seven posterior dislocations and 3 years later, the acetabular component was revised to the MDM prosthesis; the well-fixed StelKast femoral component was retained (Figure 1).

Within 3 months after revision surgery, the left hip dislocated 3 times in 1 week, when the patient bent over to retrieve an object on the ground. The first 2 dislocations were treated with closed reduction under conscious sedation at an outside emergency department.

Discussion

Recurrent dislocation and instability accounts for 22.5% of THA revisions in the United States.⁹ Until 2011, options for managing recurrent dislocation in the United States included modular component exchange, component revision for malposition, and use of constrained components.¹⁰

In 1974, Bousquet first reported use of the DM prosthesis in primary THA; the prosthesis allowed increased stability without sacrificing motion or fixation.¹ However, longer-term studies of DM components disclosed a new complication, IPD. In 2004, Lecuire and colleagues⁴ reported 7 cases of IPD occurring a mean of 10 years after implantation of the Bousquet prosthesis.

Take-Home Points

• AIPD of DM-THA is defined by dissociation within 1 year of implantation resulting from component impingement or closed reduction maneuvers.
• This is a distinct entity from “late” IPD (>1 year) from implantation as this is associated most often with polyethylene wear, component loosening, and arthrofibrosis.
• A history of DM dislocation followed by subjective “clunking,” instability, and a series of more frequent dislocations should raise concern for AIPD.
• Classic radiographic findings of AIPD include eccentric hip reduction and soft tissue radiolucency (ie, halo sign) from dissociated polyethylene component.

• Treating practitioners of AIPD should consider closed reduction with general anesthesia and sedation in the operating room to limit risk of dissociation.

Dual-mobility (DM) components were invented in the 1970s and have been used in primary and revision total hip arthroplasty (THA) in Europe ever since.¹ However, DM components are most commonly used in the treatment of recurrent hip instability, and early results have been promising.² In DM-THAs, a smaller (22-mm or 28-mm) metal femoral head snap-fits into a larger polyethylene ball (inner articulation), which articulates with a highly polished metal shell (outer articulation), which is either implanted directly in the acetabulum or placed in an uncemented acetabular cup. The 2 articulations used in these devices theoretically increase hip range of motion (ROM) and increase the inferior head displacement distance (jump distance) required for dislocation.³

However, this DM articulation with increased ROM may also cause chronic impingement of the femoral component neck or Morse taper against the outer polyethylene bearing, resulting in polyethylene wear and late intraprosthetic dissociation (IPD) (separation of inner articulation between femoral head and polyethylene liner). In 2004, Lecuire and colleagues⁴ reported 7 cases of IPD occurring a mean of 10 years after implantation during the period 1989 to 1997. In 2013, Philippot and colleagues⁵ reported that 81 of 1960 primary THAs developed IPD a mean of 9 years after implantation. These IPD cases were attributed to polyethylene wear or outer articulation blockage caused by arthrofibrosis or heterotopic ossification. Reports of acute IPD (AIPD), however, are rare. In 2011, Stigbrand and Ullmark⁶ reported 3 cases in which the DM prosthesis dislocated within 1 year after implantation. It was suggested that the inner metal head dissociated from the larger polyethylene component after attempted closed reduction for dislocation (separation of larger polyethylene component from acetabulum or acetabular liner).

DM components were unavailable to surgeons in the United States until 2011. The first US Food and Drug Administration (FDA)-approved DM device was the MDM (Modular Dual Mobility, Stryker). To our knowledge, 2 cases of AIPD with this prosthesis have been reported.^{7, 8} As with the cases in Europe, closed reduction was the suspected cause, but there was no explanation for the initial dislocation event.

In this article, we present the case of a nondemented man who developed AIPD of a THA with the MDM component and a 28-mm femoral head with a skirted neck (StelKast). His operative findings suggest a poor head-to-neck ratio caused by a larger diameter femoral neck or a skirted prosthesis, or a forceful reduction maneuver, may predispose DM components to AIPD. The patient provided written informed consent for print and electronic publication of this case report.

Case Report

In 2012, a 63-year-old man with a history of drug abuse underwent left primary THA. Seven posterior dislocations and 3 years later, the acetabular component was revised to the MDM prosthesis; the well-fixed StelKast femoral component was retained (Figure 1).

Within 3 months after revision surgery, the left hip dislocated 3 times in 1 week, when the patient bent over to retrieve an object on the ground. The first 2 dislocations were treated with closed reduction under conscious sedation at an outside emergency department.

Discussion

Recurrent dislocation and instability accounts for 22.5% of THA revisions in the United States.⁹ Until 2011, options for managing recurrent dislocation in the United States included modular component exchange, component revision for malposition, and use of constrained components.¹⁰

In 1974, Bousquet first reported use of the DM prosthesis in primary THA; the prosthesis allowed increased stability without sacrificing motion or fixation.¹ However, longer-term studies of DM components disclosed a new complication, IPD. In 2004, Lecuire and colleagues⁴ reported 7 cases of IPD occurring a mean of 10 years after implantation of the Bousquet prosthesis.

VIENNA – Oral antibiotic therapy is just as effective as intravenous treatment in curing bone and joint infections, but costs about $3,500 less.

Treating these infections with oral agents also “improves patient autonomy, as it’s not necessary to have IV lines at home,” and represents a generally wiser use of powerful antibiotics, Matthew Scarborough, MD, said at the European Society of Clinical Microbiology and Infectious Diseases annual congress.

Michele G Sullivan/Frontline Medical News

msullivan@frontlinemedcom.com

On Twitter @alz_gal

VIENNA – Oral antibiotic therapy is just as effective as intravenous treatment in curing bone and joint infections, but costs about $3,500 less.

Treating these infections with oral agents also “improves patient autonomy, as it’s not necessary to have IV lines at home,” and represents a generally wiser use of powerful antibiotics, Matthew Scarborough, MD, said at the European Society of Clinical Microbiology and Infectious Diseases annual congress.

Michele G Sullivan/Frontline Medical News

msullivan@frontlinemedcom.com

On Twitter @alz_gal

VIENNA – Oral antibiotic therapy is just as effective as intravenous treatment in curing bone and joint infections, but costs about $3,500 less.

Treating these infections with oral agents also “improves patient autonomy, as it’s not necessary to have IV lines at home,” and represents a generally wiser use of powerful antibiotics, Matthew Scarborough, MD, said at the European Society of Clinical Microbiology and Infectious Diseases annual congress.

Michele G Sullivan/Frontline Medical News

msullivan@frontlinemedcom.com

On Twitter @alz_gal

A 66-year-old woman 3 years status post hip replacement is seen for dental work. The dentist contacts the clinic for an antibiotic prescription. The patient has a penicillin allergy (rash). What do you recommend?

A. Clindamycin one dose before dental work.

B. Amoxicillin one dose before dental work.

C. Amoxicillin one dose before, one dose 4 hours after dental work.

D. Clindamycin one dose before dental work, one dose 4 hours after dental work.

E. No antibiotics.

Many patients with prosthetic joints will request antibiotics to take prior to dental procedures. Sometimes this request comes from the dental office.

When I ask patients why they feel they need antibiotics, they often reply that they were told by their orthopedic surgeons or their dentist that they would need to take antibiotics before dental procedures.

In an era when Clostridium difficile infection is a common and dangerous complication in the elderly, avoidance of unnecessary antibiotics is critical. In the United States, it is estimated that there are 240,000 patients infected with C. difficile annually, with 24,000 deaths at a cost of $6 billion.¹

Is there compelling evidence to justify giving antibiotic prophylaxis for dental procedures to patients with prosthetic joints?

References

1. Steckelberg J.M., Osmon D.R. Prosthetic joint infections. In: Bisno A.L., Waldvogel F.A., eds. Infections associated with indwelling medical devices. Third ed., Washington, D.C.: American Society of Microbiology Press, 2000:173-209.

2. J Dent Res. 2004 Feb;83(2):170-4.

3. J Clin Periodontol. 2006 Feb;33(6):401-7.

4. J Am Dent Assoc. 1997 Jul;128(7):1004-8.

5. J Am Dent Assoc. 2003 Jul;134(7):895-9.

6. Spec Care Dentist. 2009 Nov-Dec;29(6):229-31.

7. Clin Infect Dis. 2010 Jan 1;50(1):8-16.

8. J Dent (Shiraz). 2013 Mar;14(1):49-52.

9. Infect Control Hosp Epidemiol. 2017 Feb;38(2):154-61.

Dr. Paauw is professor of medicine in the division of general internal medicine at the University of Washington, Seattle, and he serves as third-year medical student clerkship director at the University of Washington. Contact Dr. Paauw at dpaauw@uw.edu.

A 66-year-old woman 3 years status post hip replacement is seen for dental work. The dentist contacts the clinic for an antibiotic prescription. The patient has a penicillin allergy (rash). What do you recommend?

A. Clindamycin one dose before dental work.

B. Amoxicillin one dose before dental work.

C. Amoxicillin one dose before, one dose 4 hours after dental work.

D. Clindamycin one dose before dental work, one dose 4 hours after dental work.

E. No antibiotics.

Many patients with prosthetic joints will request antibiotics to take prior to dental procedures. Sometimes this request comes from the dental office.

When I ask patients why they feel they need antibiotics, they often reply that they were told by their orthopedic surgeons or their dentist that they would need to take antibiotics before dental procedures.

In an era when Clostridium difficile infection is a common and dangerous complication in the elderly, avoidance of unnecessary antibiotics is critical. In the United States, it is estimated that there are 240,000 patients infected with C. difficile annually, with 24,000 deaths at a cost of $6 billion.¹

Is there compelling evidence to justify giving antibiotic prophylaxis for dental procedures to patients with prosthetic joints?

References

1. Steckelberg J.M., Osmon D.R. Prosthetic joint infections. In: Bisno A.L., Waldvogel F.A., eds. Infections associated with indwelling medical devices. Third ed., Washington, D.C.: American Society of Microbiology Press, 2000:173-209.

2. J Dent Res. 2004 Feb;83(2):170-4.

3. J Clin Periodontol. 2006 Feb;33(6):401-7.

4. J Am Dent Assoc. 1997 Jul;128(7):1004-8.

5. J Am Dent Assoc. 2003 Jul;134(7):895-9.

6. Spec Care Dentist. 2009 Nov-Dec;29(6):229-31.

7. Clin Infect Dis. 2010 Jan 1;50(1):8-16.

8. J Dent (Shiraz). 2013 Mar;14(1):49-52.

9. Infect Control Hosp Epidemiol. 2017 Feb;38(2):154-61.

Dr. Paauw is professor of medicine in the division of general internal medicine at the University of Washington, Seattle, and he serves as third-year medical student clerkship director at the University of Washington. Contact Dr. Paauw at dpaauw@uw.edu.

A 66-year-old woman 3 years status post hip replacement is seen for dental work. The dentist contacts the clinic for an antibiotic prescription. The patient has a penicillin allergy (rash). What do you recommend?

A. Clindamycin one dose before dental work.

B. Amoxicillin one dose before dental work.

C. Amoxicillin one dose before, one dose 4 hours after dental work.

D. Clindamycin one dose before dental work, one dose 4 hours after dental work.

E. No antibiotics.

Many patients with prosthetic joints will request antibiotics to take prior to dental procedures. Sometimes this request comes from the dental office.

When I ask patients why they feel they need antibiotics, they often reply that they were told by their orthopedic surgeons or their dentist that they would need to take antibiotics before dental procedures.

In an era when Clostridium difficile infection is a common and dangerous complication in the elderly, avoidance of unnecessary antibiotics is critical. In the United States, it is estimated that there are 240,000 patients infected with C. difficile annually, with 24,000 deaths at a cost of $6 billion.¹

Is there compelling evidence to justify giving antibiotic prophylaxis for dental procedures to patients with prosthetic joints?

References

1. Steckelberg J.M., Osmon D.R. Prosthetic joint infections. In: Bisno A.L., Waldvogel F.A., eds. Infections associated with indwelling medical devices. Third ed., Washington, D.C.: American Society of Microbiology Press, 2000:173-209.

2. J Dent Res. 2004 Feb;83(2):170-4.

3. J Clin Periodontol. 2006 Feb;33(6):401-7.

4. J Am Dent Assoc. 1997 Jul;128(7):1004-8.

5. J Am Dent Assoc. 2003 Jul;134(7):895-9.

6. Spec Care Dentist. 2009 Nov-Dec;29(6):229-31.

7. Clin Infect Dis. 2010 Jan 1;50(1):8-16.

8. J Dent (Shiraz). 2013 Mar;14(1):49-52.

9. Infect Control Hosp Epidemiol. 2017 Feb;38(2):154-61.

Dr. Paauw is professor of medicine in the division of general internal medicine at the University of Washington, Seattle, and he serves as third-year medical student clerkship director at the University of Washington. Contact Dr. Paauw at dpaauw@uw.edu.

Take-Home Points

• Surface landmarks are routinely used for physical examination and surgical technique.
• Common surface landmarks used in establishing arthroscopic portals may be more difficult to accurately identify than previously thought.
• The greater trochanter was the surface landmark most precisely identified by expert examiners.
• Ultrasound examination identified landmarks varied from landmarks identified by palpation alone.

Anatomical surface landmarks about the hip and lower abdomen are often referenced when placing arthroscopic portals and office-based injections.^1-3 However, the degree to which these landmarks can be reproducibly identified using only visual inspection and palpation is unknown.

Safe access to the hip joint and surrounding structures during hip arthroscopy has been a focus in the orthopedic literature. Authors have described anatomical relationships of recommended portals to neurovascular and other anatomical structures.^4-6 This information has been reported in millimeters to centimeters of safety based on cadaver dissection studies.^4-7We conducted a study to assess expert hip arthroscopists’ ability to identify, using only physical examination techniques, the anatomical structures used for reference when creating safe starting points for arthroscopic access. We hypothesized that variance in examiner-identified points would exceed safe distances from neurovascular structures for the most commonly used hip arthroscopic portals. The volunteer in this study provided written informed consent for print and electronic publication of this article.

Methods

In this study, we prospectively assessed 30 expert hip arthroscopic surgeons’ ability to identify commonly referenced surface landmarks on the adult male hip, using only inspection and manual palpation. Surgeons were defined as experts on the basis of their status as hip arthroscopy instructors at the Orthopaedic Learning Center (Rosemont, IL) for the Arthroscopy Association of North America and industry-sponsored hip arthroscopy education faculty (Arthrex). Five surface landmarks were selected for their relevance to publications on safe portal placement^2-5: anterior superior iliac spine (ASIS), tip of greater trochanter (GT), rectus origin (RO), superficial inguinal ring (SIR), and psoas tendon (PT).

A healthy adult male volunteer was placed supine on an examination table and exposed distally from the mid abdomen, with the perineum and the genital area covered bikini-style. An expert musculoskeletal ultrasonographer used a handheld musculoskeletal ultrasound transducer (Sonosite) to identify the 5 landmarks. Short- and long-axis images of each structure were obtained. The examiner applied a round (1 cm in diameter), uniquely colored adhesive label to the skin over each location. A professional photographer using a Canon digital camera and fixed mounts made precise overhead and lateral images. The positional integrity and scale of these images were confirmed with referral to constant anatomical skin features. Images were archived for analysis (Figure 1A).

After the ultrasonographer’s labels were removed, each of the 30 expert hip arthroscopic surgeons identified the structures by static physical examination (inspection and palpation only) and applied the same colored labels to the skin.

Results

Average absolute distance from examiner labels to ultrasonographer labels was 31 mm for ASIS, 24 mm for GT, 26 mm for RO, 19 mm for SIR, and 35 mm for PT (Figure 2).

Of the 30 surgeons, 1 (3%) came within 10 mm of the ultrasound for ASIS, 1 (3%) for GT, 4 (13%) for RO, 5 (17%) for SIR, and 1 (3%) for PT (Table 1).

Discussion

Others have investigated examiners’ use of palpation, compared with ultrasound, to identify common shoulder and knee structures.^8-10 In a 2011 systematic review, Gilliland and colleagues¹¹ confirmed that accuracy was improved with use of ultrasound (vs palpation) for injections in the shoulder, hip, knee, wrist, and ankle. Given the scarcity of data in this setting, we conducted the present study to assess the precision and accuracy of expert arthroscopists in identifying common surface landmarks. We hypothesized that physical examination and ultrasound examination would differ significantly in precisely and accurately identifying these landmarks.

Working with a standard awake volunteer, our test group of examiners was consistently inaccurate when they accepted ultrasonographer-placed labels as the ideal. Precision within the group, however, trended toward close agreement; examiners consistently placed labels in the same direction and approximate magnitude away from ultrasonographer labels. This suggests that a discrepancy between the ultrasonographic surface structure definitions taught to ultrasonographers and the manually identified definitions taught to surgeons for arthroscopy (training bias) can generate differences in landmark identification.

Given reported low rates of complications in the creation of standard surface anatomy portals, more data is needed to correlate whether safe distance guidelines best apply to the points identified by hip experts or the points identified by ultrasonographers. In a 2013 systematic review, Harris and colleagues⁸ found a 7.5% overall complication rate, with temporary neuropraxia 1 of the 2 most common complications. Whether adding ultrasound to physical examination for the creation of some or all portals will reduce the incidence of these problems is unknown. Regardless of the anatomical area referenced by experts for portal creation, the tight grouping of examiner marks in our study supports a consensus regarding the location of the landmarks studied.

In our study of the use of surface anatomical landmarks for the creation of portals, we analyzed 4 previously described locations: ALP, AP, PLP, and MAP. ALP, AP, and PLP directly reference at least 1 surface anatomical structure; AP references 2 anatomical structures (ASIS, GT); and MAP indirectly references ASIS and GT and directly references ALP and AP. In cadaveric and radiographic studies, 7 neurovascular structures have been described in proximity to ALP, AP, MAP, and PLP: superior gluteal nerve, sciatic nerve, femoral nerve, lateral femoral cutaneous nerve, lateral circumflex femoral artery, and medial circumflex femoral artery.^5,6 Our results showed that use of surface anatomy in AP and MAP creation most likely places structures at risk, given the overlap of examiner CIs and the previously published cadaveric^5,6 and radiographic⁷ data.

Hua and colleagues¹² confirmed the feasibility of using ultrasound for the creation of hip arthroscopy portals. More data is needed to assess how the standard palpation-and-fluoroscopy method described by Byrd³ compares with an ultrasound-guided technique in safety and cost. However, data from our study should not be used to justify a demand for ultrasound during arthroscopy portal establishment, as limitations do not permit such a recommendation.

With diagnostic injection remaining a mainstay of differential diagnosis and treatment about the hip,¹ the data presented here suggest a potential for ultrasound in enhancing outcomes. There is evidence supporting the role of image guidance in improving palpation accuracy in the area of the biceps tendon in the forearm.¹⁰ Potentially, identification and treatment of specific extra-articular structures surrounding the hip could be made safer with more routine use of ultrasound.

Limitations

This study had several limitations. The surgeons were limited to palpation and static examination of a body in its natural state. Hip arthroscopic portals typically are created under traction and after a standard perineal post is placed for hip arthroscopy. In addition, in an awake injection setting, the clinician may receive patient feedback in the form of limb movement or speech. To what degree palpation or ultrasound will be affected in these scenarios is unknown.

Another limitation is the lack of serial examination by each examiner—intrarater variability could not be gauged. In addition, with only 1 ultrasonographic examination performed, there is the potential that adding ultrasonographic examinations, or having an examiner perform serial physical examinations, could better define the precision of each component. Given the practical limitations of our volunteer’s time and the schedules of 30 expert arthroscopists, we kept the chosen study design for its single setting.

Conclusion

Visual inspection and manual palpation are standard means of identifying common surface anatomical landmarks for the creation of arthroscopy portals and the placement of injections. Our study results showed variance in landmark identification between expert examiners and an ultrasonographer. The degree of variance exceeded established neurovascular safe zones, particularly for AP and MAP. This new evidence calls for further investigation into the best, safest means of performing hip arthroscopic techniques and injection-based interventions.

Am J Orthop. 2017;46(1):E65-E70. Copyright Frontline Medical Communications Inc. 2017. All rights reserved.

Take-Home Points

• Surface landmarks are routinely used for physical examination and surgical technique.
• Common surface landmarks used in establishing arthroscopic portals may be more difficult to accurately identify than previously thought.
• The greater trochanter was the surface landmark most precisely identified by expert examiners.
• Ultrasound examination identified landmarks varied from landmarks identified by palpation alone.

Anatomical surface landmarks about the hip and lower abdomen are often referenced when placing arthroscopic portals and office-based injections.^1-3 However, the degree to which these landmarks can be reproducibly identified using only visual inspection and palpation is unknown.

Safe access to the hip joint and surrounding structures during hip arthroscopy has been a focus in the orthopedic literature. Authors have described anatomical relationships of recommended portals to neurovascular and other anatomical structures.^4-6 This information has been reported in millimeters to centimeters of safety based on cadaver dissection studies.^4-7We conducted a study to assess expert hip arthroscopists’ ability to identify, using only physical examination techniques, the anatomical structures used for reference when creating safe starting points for arthroscopic access. We hypothesized that variance in examiner-identified points would exceed safe distances from neurovascular structures for the most commonly used hip arthroscopic portals. The volunteer in this study provided written informed consent for print and electronic publication of this article.

Methods

In this study, we prospectively assessed 30 expert hip arthroscopic surgeons’ ability to identify commonly referenced surface landmarks on the adult male hip, using only inspection and manual palpation. Surgeons were defined as experts on the basis of their status as hip arthroscopy instructors at the Orthopaedic Learning Center (Rosemont, IL) for the Arthroscopy Association of North America and industry-sponsored hip arthroscopy education faculty (Arthrex). Five surface landmarks were selected for their relevance to publications on safe portal placement^2-5: anterior superior iliac spine (ASIS), tip of greater trochanter (GT), rectus origin (RO), superficial inguinal ring (SIR), and psoas tendon (PT).

A healthy adult male volunteer was placed supine on an examination table and exposed distally from the mid abdomen, with the perineum and the genital area covered bikini-style. An expert musculoskeletal ultrasonographer used a handheld musculoskeletal ultrasound transducer (Sonosite) to identify the 5 landmarks. Short- and long-axis images of each structure were obtained. The examiner applied a round (1 cm in diameter), uniquely colored adhesive label to the skin over each location. A professional photographer using a Canon digital camera and fixed mounts made precise overhead and lateral images. The positional integrity and scale of these images were confirmed with referral to constant anatomical skin features. Images were archived for analysis (Figure 1A).

After the ultrasonographer’s labels were removed, each of the 30 expert hip arthroscopic surgeons identified the structures by static physical examination (inspection and palpation only) and applied the same colored labels to the skin.

Results

Average absolute distance from examiner labels to ultrasonographer labels was 31 mm for ASIS, 24 mm for GT, 26 mm for RO, 19 mm for SIR, and 35 mm for PT (Figure 2).

Of the 30 surgeons, 1 (3%) came within 10 mm of the ultrasound for ASIS, 1 (3%) for GT, 4 (13%) for RO, 5 (17%) for SIR, and 1 (3%) for PT (Table 1).

Discussion

Others have investigated examiners’ use of palpation, compared with ultrasound, to identify common shoulder and knee structures.^8-10 In a 2011 systematic review, Gilliland and colleagues¹¹ confirmed that accuracy was improved with use of ultrasound (vs palpation) for injections in the shoulder, hip, knee, wrist, and ankle. Given the scarcity of data in this setting, we conducted the present study to assess the precision and accuracy of expert arthroscopists in identifying common surface landmarks. We hypothesized that physical examination and ultrasound examination would differ significantly in precisely and accurately identifying these landmarks.

Working with a standard awake volunteer, our test group of examiners was consistently inaccurate when they accepted ultrasonographer-placed labels as the ideal. Precision within the group, however, trended toward close agreement; examiners consistently placed labels in the same direction and approximate magnitude away from ultrasonographer labels. This suggests that a discrepancy between the ultrasonographic surface structure definitions taught to ultrasonographers and the manually identified definitions taught to surgeons for arthroscopy (training bias) can generate differences in landmark identification.

Given reported low rates of complications in the creation of standard surface anatomy portals, more data is needed to correlate whether safe distance guidelines best apply to the points identified by hip experts or the points identified by ultrasonographers. In a 2013 systematic review, Harris and colleagues⁸ found a 7.5% overall complication rate, with temporary neuropraxia 1 of the 2 most common complications. Whether adding ultrasound to physical examination for the creation of some or all portals will reduce the incidence of these problems is unknown. Regardless of the anatomical area referenced by experts for portal creation, the tight grouping of examiner marks in our study supports a consensus regarding the location of the landmarks studied.

In our study of the use of surface anatomical landmarks for the creation of portals, we analyzed 4 previously described locations: ALP, AP, PLP, and MAP. ALP, AP, and PLP directly reference at least 1 surface anatomical structure; AP references 2 anatomical structures (ASIS, GT); and MAP indirectly references ASIS and GT and directly references ALP and AP. In cadaveric and radiographic studies, 7 neurovascular structures have been described in proximity to ALP, AP, MAP, and PLP: superior gluteal nerve, sciatic nerve, femoral nerve, lateral femoral cutaneous nerve, lateral circumflex femoral artery, and medial circumflex femoral artery.^5,6 Our results showed that use of surface anatomy in AP and MAP creation most likely places structures at risk, given the overlap of examiner CIs and the previously published cadaveric^5,6 and radiographic⁷ data.

Hua and colleagues¹² confirmed the feasibility of using ultrasound for the creation of hip arthroscopy portals. More data is needed to assess how the standard palpation-and-fluoroscopy method described by Byrd³ compares with an ultrasound-guided technique in safety and cost. However, data from our study should not be used to justify a demand for ultrasound during arthroscopy portal establishment, as limitations do not permit such a recommendation.

With diagnostic injection remaining a mainstay of differential diagnosis and treatment about the hip,¹ the data presented here suggest a potential for ultrasound in enhancing outcomes. There is evidence supporting the role of image guidance in improving palpation accuracy in the area of the biceps tendon in the forearm.¹⁰ Potentially, identification and treatment of specific extra-articular structures surrounding the hip could be made safer with more routine use of ultrasound.

Limitations

This study had several limitations. The surgeons were limited to palpation and static examination of a body in its natural state. Hip arthroscopic portals typically are created under traction and after a standard perineal post is placed for hip arthroscopy. In addition, in an awake injection setting, the clinician may receive patient feedback in the form of limb movement or speech. To what degree palpation or ultrasound will be affected in these scenarios is unknown.

Another limitation is the lack of serial examination by each examiner—intrarater variability could not be gauged. In addition, with only 1 ultrasonographic examination performed, there is the potential that adding ultrasonographic examinations, or having an examiner perform serial physical examinations, could better define the precision of each component. Given the practical limitations of our volunteer’s time and the schedules of 30 expert arthroscopists, we kept the chosen study design for its single setting.

Conclusion

Visual inspection and manual palpation are standard means of identifying common surface anatomical landmarks for the creation of arthroscopy portals and the placement of injections. Our study results showed variance in landmark identification between expert examiners and an ultrasonographer. The degree of variance exceeded established neurovascular safe zones, particularly for AP and MAP. This new evidence calls for further investigation into the best, safest means of performing hip arthroscopic techniques and injection-based interventions.

Am J Orthop. 2017;46(1):E65-E70. Copyright Frontline Medical Communications Inc. 2017. All rights reserved.

Take-Home Points

• Surface landmarks are routinely used for physical examination and surgical technique.
• Common surface landmarks used in establishing arthroscopic portals may be more difficult to accurately identify than previously thought.
• The greater trochanter was the surface landmark most precisely identified by expert examiners.
• Ultrasound examination identified landmarks varied from landmarks identified by palpation alone.

Anatomical surface landmarks about the hip and lower abdomen are often referenced when placing arthroscopic portals and office-based injections.^1-3 However, the degree to which these landmarks can be reproducibly identified using only visual inspection and palpation is unknown.

Safe access to the hip joint and surrounding structures during hip arthroscopy has been a focus in the orthopedic literature. Authors have described anatomical relationships of recommended portals to neurovascular and other anatomical structures.^4-6 This information has been reported in millimeters to centimeters of safety based on cadaver dissection studies.^4-7We conducted a study to assess expert hip arthroscopists’ ability to identify, using only physical examination techniques, the anatomical structures used for reference when creating safe starting points for arthroscopic access. We hypothesized that variance in examiner-identified points would exceed safe distances from neurovascular structures for the most commonly used hip arthroscopic portals. The volunteer in this study provided written informed consent for print and electronic publication of this article.

Methods

In this study, we prospectively assessed 30 expert hip arthroscopic surgeons’ ability to identify commonly referenced surface landmarks on the adult male hip, using only inspection and manual palpation. Surgeons were defined as experts on the basis of their status as hip arthroscopy instructors at the Orthopaedic Learning Center (Rosemont, IL) for the Arthroscopy Association of North America and industry-sponsored hip arthroscopy education faculty (Arthrex). Five surface landmarks were selected for their relevance to publications on safe portal placement^2-5: anterior superior iliac spine (ASIS), tip of greater trochanter (GT), rectus origin (RO), superficial inguinal ring (SIR), and psoas tendon (PT).

A healthy adult male volunteer was placed supine on an examination table and exposed distally from the mid abdomen, with the perineum and the genital area covered bikini-style. An expert musculoskeletal ultrasonographer used a handheld musculoskeletal ultrasound transducer (Sonosite) to identify the 5 landmarks. Short- and long-axis images of each structure were obtained. The examiner applied a round (1 cm in diameter), uniquely colored adhesive label to the skin over each location. A professional photographer using a Canon digital camera and fixed mounts made precise overhead and lateral images. The positional integrity and scale of these images were confirmed with referral to constant anatomical skin features. Images were archived for analysis (Figure 1A).

After the ultrasonographer’s labels were removed, each of the 30 expert hip arthroscopic surgeons identified the structures by static physical examination (inspection and palpation only) and applied the same colored labels to the skin.

Results

Average absolute distance from examiner labels to ultrasonographer labels was 31 mm for ASIS, 24 mm for GT, 26 mm for RO, 19 mm for SIR, and 35 mm for PT (Figure 2).

Of the 30 surgeons, 1 (3%) came within 10 mm of the ultrasound for ASIS, 1 (3%) for GT, 4 (13%) for RO, 5 (17%) for SIR, and 1 (3%) for PT (Table 1).

Discussion

Others have investigated examiners’ use of palpation, compared with ultrasound, to identify common shoulder and knee structures.^8-10 In a 2011 systematic review, Gilliland and colleagues¹¹ confirmed that accuracy was improved with use of ultrasound (vs palpation) for injections in the shoulder, hip, knee, wrist, and ankle. Given the scarcity of data in this setting, we conducted the present study to assess the precision and accuracy of expert arthroscopists in identifying common surface landmarks. We hypothesized that physical examination and ultrasound examination would differ significantly in precisely and accurately identifying these landmarks.

Working with a standard awake volunteer, our test group of examiners was consistently inaccurate when they accepted ultrasonographer-placed labels as the ideal. Precision within the group, however, trended toward close agreement; examiners consistently placed labels in the same direction and approximate magnitude away from ultrasonographer labels. This suggests that a discrepancy between the ultrasonographic surface structure definitions taught to ultrasonographers and the manually identified definitions taught to surgeons for arthroscopy (training bias) can generate differences in landmark identification.

Given reported low rates of complications in the creation of standard surface anatomy portals, more data is needed to correlate whether safe distance guidelines best apply to the points identified by hip experts or the points identified by ultrasonographers. In a 2013 systematic review, Harris and colleagues⁸ found a 7.5% overall complication rate, with temporary neuropraxia 1 of the 2 most common complications. Whether adding ultrasound to physical examination for the creation of some or all portals will reduce the incidence of these problems is unknown. Regardless of the anatomical area referenced by experts for portal creation, the tight grouping of examiner marks in our study supports a consensus regarding the location of the landmarks studied.

In our study of the use of surface anatomical landmarks for the creation of portals, we analyzed 4 previously described locations: ALP, AP, PLP, and MAP. ALP, AP, and PLP directly reference at least 1 surface anatomical structure; AP references 2 anatomical structures (ASIS, GT); and MAP indirectly references ASIS and GT and directly references ALP and AP. In cadaveric and radiographic studies, 7 neurovascular structures have been described in proximity to ALP, AP, MAP, and PLP: superior gluteal nerve, sciatic nerve, femoral nerve, lateral femoral cutaneous nerve, lateral circumflex femoral artery, and medial circumflex femoral artery.^5,6 Our results showed that use of surface anatomy in AP and MAP creation most likely places structures at risk, given the overlap of examiner CIs and the previously published cadaveric^5,6 and radiographic⁷ data.

Hua and colleagues¹² confirmed the feasibility of using ultrasound for the creation of hip arthroscopy portals. More data is needed to assess how the standard palpation-and-fluoroscopy method described by Byrd³ compares with an ultrasound-guided technique in safety and cost. However, data from our study should not be used to justify a demand for ultrasound during arthroscopy portal establishment, as limitations do not permit such a recommendation.

With diagnostic injection remaining a mainstay of differential diagnosis and treatment about the hip,¹ the data presented here suggest a potential for ultrasound in enhancing outcomes. There is evidence supporting the role of image guidance in improving palpation accuracy in the area of the biceps tendon in the forearm.¹⁰ Potentially, identification and treatment of specific extra-articular structures surrounding the hip could be made safer with more routine use of ultrasound.

Limitations

This study had several limitations. The surgeons were limited to palpation and static examination of a body in its natural state. Hip arthroscopic portals typically are created under traction and after a standard perineal post is placed for hip arthroscopy. In addition, in an awake injection setting, the clinician may receive patient feedback in the form of limb movement or speech. To what degree palpation or ultrasound will be affected in these scenarios is unknown.

Another limitation is the lack of serial examination by each examiner—intrarater variability could not be gauged. In addition, with only 1 ultrasonographic examination performed, there is the potential that adding ultrasonographic examinations, or having an examiner perform serial physical examinations, could better define the precision of each component. Given the practical limitations of our volunteer’s time and the schedules of 30 expert arthroscopists, we kept the chosen study design for its single setting.

Conclusion

Visual inspection and manual palpation are standard means of identifying common surface anatomical landmarks for the creation of arthroscopy portals and the placement of injections. Our study results showed variance in landmark identification between expert examiners and an ultrasonographer. The degree of variance exceeded established neurovascular safe zones, particularly for AP and MAP. This new evidence calls for further investigation into the best, safest means of performing hip arthroscopic techniques and injection-based interventions.

Am J Orthop. 2017;46(1):E65-E70. Copyright Frontline Medical Communications Inc. 2017. All rights reserved.