Can Dual Mobility Cups Reduce Revision and Dislocation Risks? An Analysis of 107,528 Primary Total Hip Arthroplasties in the United States

BACKGROUND

Dual mobility acetabular cups (DMC) were designed to increase the effective femoral head size and improve stability with the goal of reducing revision risk at the potential cost of polyethylene thickness. We sought to evaluate revision risk following primary elective total hip arthroplasty with DMC compared to highly cross-linked polyethylene (XLPE).

METHODS

A cohort study was conducted using data from a Kaiser Permanente's total joint arthroplasty registry. Patients ≥18 years who underwent primary elective total hip arthroplasty using DMC, unipolar Metal-on-XLPE (MoXLPE), or unipolar Ceramic-on-XLPE (CoXLPE) were identified (2010 to 2021). The final sample comprised 2,219 DMC, 48,251 MoXLPE, and 57,058 CoXLPE. Multiple Cox proportional hazard regressions were used to evaluate aseptic revision and any dislocation regardless of revision within 6 years follow-up.

RESULTS

In adjusted analyses, no differences in aseptic revision risk were observed for MoXLPE (hazard ratio [HR] = 1.04, 95% confidence interval [CI] = 0.72 to 1.51) or CoXLPE (HR = 0.98, 95% CI = 0.69 to 1.40) compared to DMC. No differences in dislocation risk were observed for MoXLPE (HR = 1.42, 95% CI = 0.93 to 2.15) or CoXLPE (HR = 1.25, 95% CI = 0.84 to 1.87) compared to DMC.

CONCLUSIONS

In a US-based cohort, 6-year aseptic revision risk of DMC was similar to metal or ceramic femoral head unipolar constructs. Furthermore, no difference in dislocation risk was observed. Continued longer-term follow-up may reveal if there is a reduced risk of dislocation that comes at the cost of increased late revision.

LEVEL OF EVIDENCE

Level III.

Preoperative Patient Optimization: Outcomes from Elective Total Joint Arthroplasty in a Large US Healthcare System

INTRODUCTION

Patient factors are known to affect outcomes in arthroplasty surgery. A preoperative program to address modifiable factors may aid in more appropriate patient selection. We sought to assess patient selection and 90-day postoperative outcomes for total joint arthroplasty (TJA) candidates before and after implementation of a preoperative optimization protocol.

METHODS

A retrospective time-trend study using data from an integrated healthcare system's total joint replacement registry was done. The study sample consisted of patients aged 18 years or older who underwent primary elective total hip arthroplasty (THA) and total knee arthroplasty (TKA) for osteoarthritis between 2009 and 2019. Patients were divided into two cohorts: procedures performed from 2009 to 2013 ("preoptimization protocol") and those from 2015 to 2019 ("postoptimization protocol"); 2014 was excluded because an evidence-based preoperative patient optimization protocol was progressively implemented throughout the year. Patient characteristics, optimization factors, and 90-day outcomes (including emergency department [ED] visits, readmission, all-cause revision, deep infection, venous thromboembolism, and mortality) were compared between the two cohorts using the Pearson chi-square test or Wilcoxon test.

RESULTS

The study sample included 25,925 THA and 60,484 TKA. In the THA cohort, 10,364 (40.0%) and 15,561 (60.0%) were from the preoptimization and postoptimization cohorts, respectively. The postoptimization THA cohort saw lower rates of ED visits (12.1% vs. 9.4%, P < 0.001) and readmissions (5.6% vs. 3.8%, P < 0.001). In the TKA cohort, 24,054 (39.8%) and 36,430 (60.2%) were from the preoptimization and postoptimization cohorts, respectively. The postoptimization TKA cohort saw lower rates of ED visits (13.1% vs. 11.9%, P < 0.001), readmissions (5.6% vs. 3.0%, P < 0.001), all-cause revisions (0.5% vs. 0.3%, P = 0.003), venous thromboembolism (1.3% vs. 0.9%, P < 0.001), and mortality (0.3% vs. 0.2%, P = 0.011).

DISCUSSION

An evidence-based protocol to improve patient selection based on modifiable patient factors was adopted by orthopaedic surgeons in the system and utilization of the protocol before TJA was associated with fewer postoperative complications over time.

LEVEL OF EVIDENCE

Level IV.

Cause-Specific Stem Revision Risk in Primary Total Hip Arthroplasty Using Cemented vs Cementless Femoral Stem Fixation in a US Cohort

BACKGROUND

We sought to evaluate the cause-specific revision risk following hybrid (cemented stem mated to a cementless acetabular implant) vs cementless total hip arthroplasty (THA) in a US cohort.

METHODS

Primary elective THA for osteoarthritis was identified using Kaiser Permanente's Total Joint Replacement Registry (2001-2018). Multivariable Cox regression was used to evaluate cause-specific revision, including aseptic loosening, infection, instability, and periprosthetic fracture (PPF), for hybrid vs cementless THA. Analysis was stratified by age (<65, 65-74, and ≥75 years) and gender.

RESULTS

The study cohort comprised 88,830 THAs, including 4539 (5.1%) hybrid THAs. In stratified analysis, hybrid THA had a higher revision risk for loosening in females in all 3 age subgroups. A lower risk of revision for PPF was observed following hybrid THA in females aged ≥75 years. For females ≥75 years, cementless THA had an excess PPF risk of 0.9% while hybrid THA had an excess loosening risk of 0.2%, translating to a theoretical prevention of 10 PPF revisions but a price of 3 loosening revisions per 1000 hybrid THAs. No difference in revision risk was observed in males.

CONCLUSION

We observed differences in cause-specific revision risks by method of stem fixation which depended upon patient age and gender. Although the trend toward all cementless fixation continue, there may be a role for hybrid fixation in females ≥75 years to mitigate risk for revision due to PPF at the potential cost of a slight increase in longer term aseptic loosening.

LEVEL OF EVIDENCE

Level III.

The effect of a statewide COVID-19 shelter-in-place order on shoulder arthroplasty for proximal humerus fracture volume and length of stay

Background

Although the COVID-19 pandemic has disrupted elective shoulder arthroplasty throughput, traumatic shoulder arthroplasty procedures are less apt to be postponed. We sought to evaluate shoulder arthroplasty utilization for fracture during the COVID-19 pandemic and California's associated shelter-in-place order compared to historical controls.

Methods

We conducted a cohort study with historical controls, identifying patients who underwent shoulder arthroplasty for proximal humerus fracture in California using our integrated electronic health record. The time period of interest was following the implementation of the statewide shelter-in-place order: March 19, 2020-May 31, 2020. This was compared to three historical periods: January 1, 2020-March 18, 2020, March 18, 2019-May 31, 2019, and January 1, 2019-March 18, 2019. Procedure volume, patient characteristics, in-hospital length of stay, and 30-day events (emergency department visit, readmission, infection, pneumonia, and death) were reported. Changes over time were analyzed using linear regression adjusted for usual seasonal and yearly changes and age, sex, comorbidities, and postadmission factors.

Results

Surgical volume dropped from an average of 4.4, 5.2, and 2.6 surgeries per week in the historical time periods, respectively, to 2.4 surgeries per week after shelter-in-place. While no more than 30% of all shoulder arthroplasty procedures performed during any given week were for fracture during the historical time periods, arthroplasties performed for fracture was the overwhelming primary indication immediately after the shelter-in-place order. More patients were discharged the day of surgery (+33.2%, P = .019) after the shelter-in-place order, but we did not observe a change in any of the corresponding 30-day events.

Conclusions

The volume of shoulder arthroplasty for fracture dropped during the time of COVID-19. The reduction in volume could be due to less shoulder trauma due to shelter-in-place or a change in the indications for arthroplasty given the perceived higher risks associated with intubation and surgical care. We noted more patients undergoing shoulder arthroplasty for fracture were safely discharged on the day of surgery, suggesting this may be a safe practice that can be adopted moving forward.

Level of Evidence

Level III; Retrospective Case-control Comparative Study

Patients With a History of a Cardiac Implantable Electronic Device Have a Higher Likelihood of 90-Day Cardiac Events After Total Joint Arthroplasty: A Matched Cohort Study

INTRODUCTION

We sought to identify the incidence of new 90-day cardiac events, 90-day mortality, 90-day unplanned readmissions, and 30-day emergency department (ED) visits after total joint arthroplasty (TJA) in patients with a history of a cardiac implantable electronic device (CIED) and compare these outcomes in TJA patients without a CIED.

METHODS

Kaiser Permanente's Cardiac Device and Total Joint Replacement Registries were used to identify elective primary TJA performed for osteoarthritis. TJA with a CIED was matched with TJA without a CIED (n = 365 pairs) on patient characteristics, demographics, and procedure type. A McNemar test was used to evaluate categorical outcomes.

RESULTS

Of the TJA with a CIED, there were 24 cardiac events (6.6%), 1 mortality (0.3%), 30 readmissions (8.2%), and 39 ED visits (10.7%). TJA patients with a CIED had a higher likelihood of cardiac events (odds ratio [OR] = 3.14, 95% confidence interval [CI] = 1.28 to 8.08). No difference was observed in mortality (OR = 0.50, 95% CI = 0.02 to 6.98), readmissions (OR = 1.26, 95% CI = 0.71 to 2.25), or ED visits (OR = 1.15, 95% CI = 0.71 to 1.88).

CONCLUSION

In our matched cohort study, TJA patients with a history of a CIED had a higher likelihood of incident 90-day cardiac events when compared with patients without a CIED without a difference observed for 90-day mortality, unplanned readmission, and 30-day ED visit.

LEVEL OF EVIDENCE

Level III.

Lumbar Spine Fusion Patients See Similar Improvements in Physical Activity Level to Non-Spine Fusion Patients Following Total Hip Arthroplasty

BACKGROUND

The impact of prior lumbar spinal fusion on the change in physical activity level following total hip arthroplasty (THA) has not been thoroughly examined. Therefore, we sought to compare the change in physical activity level following THA for patients with and without a history of lumbar spine fusion.

METHODS

Patients who underwent primary elective THA were identified using an integrated healthcare system's Total Joint Replacement Registry (2010-2013). Prior lumbar spine fusion was identified using the healthcare system's Spine Registry. Physical activity was self-reported by patients and measured in min/wk. Generalized linear models were used to evaluate the association between prior spine fusion and the change in physical activity from 1 year pre-THA to 1-2 years post-THA.

RESULTS

Of 11,416 THAs, 90 (0.8%) had a history of lumbar spinal fusion. Patients with a prior lumbar fusion had a median physical activity level of 28 min/wk prior to THA compared to 45 min/wk in the patients with no history of lumbar spinal fusion. One year after THA, patients with a history of lumbar spinal fusion reported a median of 120 min/wk of physical activity compared to 150 min/wk for patients without a history of lumbar spinal fusion. The difference in physical activity level change between groups was not statistically significant (estimate = -23.1, 95% confidence interval -62.1 to 15.9, P = .246).

CONCLUSION

Patients with prior lumbar fusion were found to have lower self-reported physical activity levels than patients without spine fusion both before and after THA surgery. However, both groups saw the same degree of improvement in physical activity level following THA. These findings may help in counseling patients who have had a prior lumbar spine fusion and in setting appropriate expectations prior to THA.

Kaiser Permanente: Joint Arthroplasty in an Integrated Capitated Care Delivery Model

BACKGROUND

Total joint arthroplasty is a successful operation with increasing prevalence in the United States. Kaiser Permanente has been using multiple tools to optimize patient outcomes while keeping health-care expenditures in check.

METHODS

We describe the patient, surgeon, and hospital perspective toward the delivery of sustainable arthroplasty care for a growing elderly population. Quality metrics for each stakeholder are presented.

RESULTS

Kaiser Permanente optimizes value for the patient, surgeon, and hospital with the use of evidence-based integrated care pathways and a national joint arthroplasty registry.

CONCLUSION

A continued focus on value-driven care will provide continued efficiency in a time of growth with maintenance of excellent outcomes.

Risk Factors for Reaching the Post-Operative Transfusion Trigger in a Community Primary Total Knee Arthroplasty Population

BACKGROUND

Little data exist to evaluate an individual's pre-operative risk of blood transfusion following total knee arthroplasty (TKA). Our aim is to identify the risk factors associated with reaching the transfusion trigger of Hb <8 g/dL (TT8) following surgery and how perioperative tranexamic acid (TXA) affects that outcome.

METHODS

Using a retrospective cohort study design, routine, unilateral TKAs performed between 2011 and 2013 in 19 hospitals were reviewed. Patients hospitalized ≤1 day or ≥4 days were excluded. Demographic data, clinical characteristics, and potential confounders were included in statistical models. Data were abstracted from electronic clinical and utilization databases. The main outcome was the risk of reaching the TT8. The primary exposure was use of single dose intravenous TXA. Logistic regression was used to model the adjusted association between TXA usage and post-operative risk of reaching TT8.

RESULTS

A total of 10,518 TKAs met criteria; 2566 (24.3%) received TXA (+TXA). The proportion that reached the TT8 was 2.1% for + TXA and 5.3% for -TXA (P < .0001). Pre-operative Hb levels were associated with increasing odds of reaching the TT8. Increasing age was weakly associated with this outcome. The odds of reaching the TT8 were lower for patients who had received TXA, had increasing body mass index, and surgical duration in the third quartile.

CONCLUSION

Not receiving TXA within 24 hours of TKA and pre-operative Hb levels <13 g/dL were independently associated with the odds of reaching the post-operative TT8 following a primary TKA.

Midterm-Adjusted Survival Comparing the Best Performing Unicompartmental and Total Knee Arthroplasties in a Registry

BACKGROUND

Recent literature suggests that the difference in revision risk between unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) can be influenced by surgeon volume and other confounders. We hypothesized that implant selection might decrease the relative risk of revision in an adjusted model.

METHODS

We selected the best performing (BP) primary UKAs and TKAs performed for osteoarthritis between January 2001 and December 2012 collected through a joint replacement registry. We compared aseptic and all-cause risk of revision using a surgeon-stratified Cox regression model with propensity score adjustment.

RESULTS

One thousand fifty-four UKAs were compared with 74,185 TKAs. The rate for all-cause revision was lower for UKAs (2.1%) than for TKAs (2.4%), whereas the rate for aseptic revision was higher for UKAs (2.0%) than TKAs (1.4%). The adjusted risk of aseptic revision was not significantly higher for UKA than TKA (hazard ratio = 2.02 [0.68, 5.96], P = .203) or all-cause revision (hazard ratio = 1.24 [0.52, 2.98], P = .603).

CONCLUSION

When comparing the survivorship of the BP UKAs to the BP TKAs in our registry, the adjusted risk of revision remained higher for UKAs than for TKAs, although the difference did not reach statistical significance.

Poorer Arthroscopic Outcomes of Mild Dysplasia With Cam Femoroacetabular Impingement Versus Mixed Femoroacetabular Impingement in Absence of Capsular Repair

PURPOSE

To compare outcomes of mild dysplasia with cam femoroacetabular impingement (FAI) vs mixed FAI with hip arthroscopy without capsular repair.

METHODS

A retrospective review of a 2009 to 2010 multicenter prospective outcome study was performed comparing a cohort with mild dysplasia and cam femoroacetabular impingement (cohort D) to a cohort with mixed FAI (cohort M). Outcome measures included Nonarthritic Hip Score (NAHS) and satisfaction with minimum 2-year follow-up.

RESULTS

Of 150 patients/159 hips enrolled in the initial prospective outcome study, 10 patients/10 hips had acetabular dysplasia and 8 patients met the inclusion criteria. Cohort D had 8 patients (5 female) of mean age 49.6 years with mean lateral center-edge angle (LCEA) of 19° (range, 16°-24°) demonstrating a mean change in NAHS of +20.00 at 3 months (P = .25), +14.33 at 12 months (P = .03), and -0.75 at 24 months (P = .74). Mean satisfaction was 2.88 out of 5. Cohort M had 69 patients (32 female) of mean age 38.6 years with a mean LCEA of 33° (range, 25°-38°) demonstrating a mean change in NAHS of +12.09 at 3 months (P < .0001), +20.39 at 12 months (P < .0001), and +21.99 at 24 months (P < .0001). Mean satisfaction was 3.58 out of 5. Cohort D demonstrated significantly less improvement in NAHS (P = .002) and a difference of -31.06 points compared to cohort M at minimum 2-year follow-up. Dysplasia was the only statistically significant predictor of poorer outcomes.

CONCLUSION

The common combination of mild dysplasia and cam FAI has poorer outcomes than mixed FAI following arthroscopic surgery without capsular repair.

Multicenter outcomes of arthroscopic surgery for femoroacetabular impingement in the community hospital setting

The purpose of this study is to determine multi-center outcomes from arthroscopic surgery for femoroacetabular impingement in the community hospital setting. A prospective design with 2-year minimum follow-up using the nonarthritic hip score (NAHS), a 100-point scale of perceived post-operative change for pain, activities of daily living, sports activities, and patient satisfaction was implemented at three community hospitals. Of 150 enrolled patients (159 hips) with mean age of 40 years (range, 12–73), there was 81% participation. Mean NAHS at preoperative was 54.9, 3 months: 66.6, 12 months: 74.9 and 24 months: 75.4. This represents a 20.5-point improvement in NAHS (P < 0.001). On the 100-point scale, pain was rated +73.5, ADL’s: +76.2 and sports: +68.6. 64% of patients were satisfied with their surgical outcome. Conversion arthroplasty rate was 8.8% and complication rate was 2.5%. In conclusion, arthroscopic surgery for symptomatic femoroacetabular impingement in the community setting provides safe and successful outcomes.

Antibiotic cement was associated with half the risk of re-revision in 1,154 aseptic revision total knee arthroplasties

BACKGROUND AND PURPOSE

Aseptic revisions comprise 80% of revision total knee arthroplasties (TKAs). We determined the incidence of re-revision TKA, the reasons for re-revision, and risk factors associated with these procedures.

PATIENTS AND METHODS

We conducted a retrospective cohort study of 1,154 patients who underwent aseptic revision TKA between 2002 and 2013 and were followed prospectively by a total joint replacement registry in the USA. Revision was defined as any operation in which an implanted component was replaced. Patient-, surgeon-, and procedure-related risk factors were evaluated. Survival analyses were conducted.

RESULTS

There were 114 re-revisions (10%) with a median time to reoperation of 3.6 years (interquartile range (IQR): 2.6-5.2). The infection rate was 2.9% (34/1,154) and accounted for 30% of re-revisions (34 of 114). In adjusted models, use of antibiotic-loaded cement was associated with a 50% lower risk of all-cause re-revision surgery (hazard ratio (HR) = 0.5, 95% CI: 0.3-0.9), age with a 20% lower risk for every 10-year increase (HR = 0.8, CI: 0.7-1.0), body mass index (BMI) with a 20% lower risk for every 5-unit increase (HR = 0.8, CI: 0.7-1.0), and a surgeon's greater cumulative experience (≥ 20 cases vs. < 20 cases) with a 3 times higher risk of re-revision (HR = 2.8, CI: 1.5-5).

INTERPRETATION

Revised TKAs were at high risk of subsequent failure. The use of antibiotic-loaded cement, higher age, and higher BMI were associated with lower risk of further revision whereas a higher degree of surgeon experience was associated with higher risk.

Risk calculators predict failures of knee and hip arthroplasties: findings from a large health maintenance organization

BACKGROUND

Considering the cost and risk associated with revision Total knee arthroplasty (TKAs) and Total hip arthroplasty (THAs), steps to prevent these operations will help patients and reduce healthcare costs. Revision risk calculators for patients may reduce revision surgery by supporting clinical decision-making at the point of care.

QUESTIONS/PURPOSES

We sought to develop a TKA and THA revision risk calculator using data from a large health-maintenance organization's arthroplasty registry and determine the best set of predictors for the revision risk calculator.

METHODS

Revision risk calculators for THAs and TKAs were developed using a patient cohort from a total joint replacement registry and data from a large US integrated healthcare system. The cohort included all patients who had primary procedures performed in our healthcare system between April 2001 and July 2008 and were followed until January 2014 (TKAs, n = 41,750; THAs, n = 22,721), During the study period, 9% of patients (TKA = 3066/34,686; THA=1898/20,285) were lost to followup and 7% died (TKA= 2350/41,750; THA=1419/20,285). The outcome of interest was revision surgery and was defined as replacement of any component for any reason within 5 years postoperatively. Candidate predictors for the revision risk calculator were limited to preoperative patient demographics, comorbidities, and procedure diagnoses. Logistic regression models were used to identify predictors and the Hosmer-Lemeshow goodness-of-fit test and c-statistic were used to choose final models for the revision risk calculator.

RESULTS

The best predictors for the TKA revision risk calculator were age (odds ratio [OR], 0.96; 95% CI, 0.95-0.97; p < 0.001), sex (OR, 0.84; 95% CI, 0.75-0.95; p = 0.004), square-root BMI (OR, 1.05; 95% CI, 0.99-1.11; p = 0.140), diabetes (OR, 1.32; 95% CI, 1.17-1.48; p < 0.001), osteoarthritis (OR, 1.16; 95% CI, 0.84-1.62; p = 0.368), posttraumatic arthritis (OR, 1.66; 95% CI, 1.07-2.56; p = 0.022), and osteonecrosis (OR, 2.54; 95% CI, 1.31-4.92; p = 0.006). The best predictors for the THA revision risk calculator were sex (OR, 1.24; 95% CI, 1.05-1.46; p = 0.010), age (OR, 0.98; 95% CI, 0.98-0.99; p < 0.001), square-root BMI (OR, 1.07; 95% CI, 1.00-1.15; p = 0.066), and osteoarthritis (OR, 0.85; 95% CI, 0.66-1.09; p = 0.190).

CONCLUSIONS

Study model parameters can be used to create web-based calculators. Surgeons can enter personalized patient data in the risk calculators for identification of risk of revision which can be used for clinical decision making at the point of care. Future prospective studies will be needed to validate these calculators and to refine them with time.

LEVEL OF EVIDENCE

Level III, prognostic study.

Revision total hip arthoplasty: factors associated with re-revision surgery

BACKGROUND

The survivorship of implants after revision total hip arthroplasty and risk factors associated with re-revision are not well defined. We evaluated the re-revision rate with use of the institutional total joint replacement registry. The purpose of this study was to determine patient, implant, and surgeon factors associated with re-revision total hip arthroplasty.

METHODS

A retrospective cohort study was conducted. The total joint replacement registry was used to identify patients who had undergone revision total hip arthroplasty for aseptic reasons from April 1, 2001, to December 31, 2010. The end point of interest was re-revision total hip arthroplasty. Risk factors evaluated for re-revision total hip arthroplasty included: patient risk factors (age, sex, body mass index, race, and general health status), implant risk factors (fixation type, bearing surface, femoral head size, and component replacement), and surgeon risk factors (volume and experience). A multivariable Cox proportional hazards model was used.

RESULTS

Six hundred and twenty-nine revision total hip arthroplasties with sixty-three (10%) re-revisions were evaluated. The mean cohort age (and standard deviation) was 57.0 ± 12.4 years, the mean body mass index (and standard deviation) was 29.5 ± 6.1 kg/m(2), and most of the patients were women (64.5%) and white (81.9%) and had an American Society of Anesthesiologists score of <3 (52.9%). The five-year implant survival after revision total hip arthroplasty was 86.8% (95% confidence interval, 83.57% to 90.25%). In adjusted models, age, total number of revision surgical procedures performed by the surgeon, fixation, and bearing surface were associated with the risk of re-revision. For every ten-year increase in patient age, the hazard ratio for re-revision decreases by a factor of 0.72 (95% confidence interval, 0.58 to 0.90). For every five revision surgical procedures performed by a surgeon, the risk of revision decreases by a factor of 0.93 (95% confidence interval, 0.86 to 0.99). At the time of revision, a new or retained cemented femoral implant or all-cemented hip implant increases the risk of revision by a factor of 3.19 (95% confidence interval, 1.22 to 8.38) relative to a retained or new uncemented hip implant. A ceramic on a highly cross-linked polyethylene bearing articulation decreases the hazard relative to metal on highly cross-linked polyethylene by a factor of 0.32 (95% confidence interval, 0.11 to 0.95). Metal on constrained bearing increases the hazard relative to metal on highly cross-linked polyethylene by a factor of 3.32 (95% confidence interval, 1.16 to 9.48).

CONCLUSIONS

When evaluating patient, implant, and surgical factors at the time of revision total hip arthroplasty, age, surgeon experience, implant fixation, and bearing surfaces had significant impacts on the risk of re-revision.

Risk factors for total hip arthroplasty aseptic revision

The purpose of this study was to evaluate patient, operative, implant, surgeon, and hospital factors associated with aseptic revision after primary THA in patients registered in a large US Total Joint Replacement Registry. A total of 35,960 THAs registered from 4/2001-12/2010 were evaluated. The 8-year survival rate was 96.7% (95% CI 96.4%-97.0%). Females had a higher risk of aseptic revision than males. Hispanic and Asian patients had a lower risk of revision than white patients. Ceramic-on-ceramic, ceramic-on-conventional polyethylene, and metal-on-conventional polyethylene bearing surfaces had a higher risk of revision than metal-on-highly cross-linked polyethylene. Body mass index, health status, diabetes, diagnosis, fixation, approach, bilateral procedures, head size, surgeon fellowship training, surgeon and hospital volume were not revision risk factors.

Same-day versus staged bilateral total knee arthroplasty poses no increase in complications in 6672 primary procedures

We examined the assumption that patients undergoing same-day bilateral total knee arthroplasty (TKA) have a higher incidence of major peri-operative complications than patients who stage their procedures over the course of a year. Between April 2001 and March 2007, prospective data were collected using a total joint registry. Patients undergoing primary, bilateral, same-day, TKAs were compared to patients undergoing primary, staged, bilateral TKAs within 12 months of the index operation. A total of 2441 TKAs were performed on the same day, while 4231 were staged. There were no significant differences in 90-day mortality, thrombotic events and infections between the two groups. Performing same-day bilateral TKA does not predispose patients to increased cumulative incidence of major complications over staged arthroplasty.

Surgeon, implant, and patient variables may explain variability in early revision rates reported for unicompartmental arthroplasty

BACKGROUND

The reported revision rates for cemented unicompartmental knee arthroplasties have varied widely. The effect of implant selection, patient characteristics, and surgeon characteristics on revision risk has not been evaluated fully. The purpose of the present study was to determine the impact of these variables on the risk for aseptic revision arthroplasty.

METHODS

We identified all cemented primary unicompartmental knee arthroplasties performed in our health-care system from 2002 to 2009 (median follow-up time = 2.6 years) to assess the risk for aseptic revision. A multivariate marginal Cox proportional-hazards model with robust standard errors (to adjust for the nesting of surgical cases within surgeons) was used to calculate the differential risk for revision of implants after adjusting for surgeon and hospital volume of unicompartmental knee arthroplasties performed; surgeon experience with unicompartmental knee arthroplasties at the time of surgery; surgeon fellowship training; and patient age, sex, weight, body mass index, and American Society of Anesthesiologists (ASA) score.

RESULTS

A total of 1746 unicompartmental knee arthroplasties were identified. The overall revision rate during the study period was 4.98% (95% confidence interval [CI], 4.0% to 6.1%). In a multivariate Cox model, the hazard ratio (HR) for aseptic revision relative to a modern, fixed, metal-backed tibial bearing was significantly higher for an all-polyethylene tibial tray (HR = 3.85, 95% CI = 1.54 to 9.63, p = 0.004) but not significantly higher for a mobile-bearing implant (HR = 2.42, 95% CI = 0.55 to 10.65, p = 0.242) or an older-design, fixed, metal-backed bearing (HR = 1.89, 95% CI = 0.67 to 5.33, p = 0.23). Younger age was associated with increased risk (age less than fifty-five years compared with more than sixty-five years: HR = 4.83, 95% CI = 2.60 to 8.96, p < 0.001), and a higher ASA score (≥3 compared with <3 points: HR = 0.54, 95% CI = 0.32 to 0.93, p = 0.027) and a greater mean yearly surgeon volume of unicompartmental knee arthroplasties (twelve or fewer compared with more than twelve: HR = 2.18, 95% CI = 1.28 to 3.74, p = 0.004) were associated with reduced risk.

CONCLUSIONS

Implant selection can have a considerable effect on the risk for aseptic revision following a cemented unicompartmental knee arthroplasty, as can patient and surgeon factors. Therefore, the variation among risk estimates reported in the literature for unicompartmental knee arthroplasty revision may be explained by differences in patient characteristics and implant selection as well as the surgeons' yearly volume of unicompartmental knee arthroplasties.

Risk factors for total knee arthroplasty aseptic revision

Using a Total Joint Replacement Registry, patient, operative, implant, surgeon, and hospital risk factors associated with aseptic revision after primary total knee arthroplasty (TKA) were evaluated. From 04/2001 to 12/31/2010 64,017 primary TKA cases, followed for a median time of 2.9 years, were registered and included in the analysis. Patients were predominantly female, white, with osteoarthritis, and obese. The crude aseptic revision rate is 1.3% (N=826). The cumulative survival for aseptic revision at 8 years is 97.6% (95% CI 97.3%-97.8%). Adjusted models revealed that age, race, body mass index, diabetic status, bilateral procedures, high-flex implants, and the LCS mobile bearing knee are associated with risk of revision. Gender, general health status, diagnosis, surgeon fellowship training, surgeon volume, hospital volume, fixation, and bearing surface material were not associated with risk of aseptic revision. Recognition of surgical factors associated with TKA failures can help the surgeons with their choices of surgical techniques and implants.

Does pre-coating total knee tibial implants affect the risk of aseptic revision?

We evaluated the impact of pre-coating the tibial component with polymethylmethacrylate (PMMA) on implant survival in a cohort of 16 548 primary NexGen total knee replacements (TKRs) in 14 113 patients. In 13 835 TKRs a pre-coated tray was used while in 2713 TKRs the non-pre-coated version of the same tray was used. All the TKRs were performed between 2001 and 2009 and were cemented. TKRs implanted with a pre-coated tibial component had a lower cumulative survival than those with a non-pre-coated tibial component (p = 0.01). After adjusting for diagnosis, age, gender, body mass index, American Society of Anesthesiologists grade, femoral coupling design, surgeon volume and hospital volume, pre-coating was an independent risk factor for all-cause aseptic revision (hazard ratio 2.75, p = 0.006). Revision for aseptic loosening was uncommon for both pre-coated and non-pre-coated trays (rates of 0.12% and 0%, respectively). Pre-coating with PMMA does not appear to be protective of revision for this tibial tray design at short-term follow-up.

Short-term outcomes of unresurfaced patellas in total knee arthroplasty

Selective patellar resurfacing continues in total knee arthroplasty (TKA). We define the demographics of patients selected for this procedure and report their short-term, aseptic revision rate. A community-based Total Joint Replacement Registry (TJRR) comprising 39,000 TKAs with median follow-up of 24.5 months was evaluated. Patients who underwent bicompartmental TKA were younger (p < 0.001), suffered posttraumatic arthrosis (p < 0.001), and receive hybrid fixation (p < 0.001). In multivariate analysis, the unresurfaced patella is an independent risk factor for early revision with a relative increased risk of 2.3 (95% CI, 1.4-3.7). The cumulative survivorship at 6 years for tricompartmental TKA is 98.1 versus 93.6% for bicompartmental knees (p < 0.001). Despite selecting patients with presumably healthier patellofemoral joints for bicompartmental TKA, the unresurfaced patella remains a risk factor for early revision.

Sex and risk of hip implant failure: assessing total hip arthroplasty outcomes in the United States

IMPORTANCE

The role of sex in relationship to implant failure after total hip arthroplasty (THA) is important for patient management and device innovation.

OBJECTIVE

To evaluate the association of sex with short-term risk of THA revision after adjusting for patient, implant, surgery, surgeon, and hospital confounders.

DESIGN AND SETTING

A prospective cohort of patients enrolled in a total joint replacement registry from April 1, 2001, through December 31, 2010.

PARTICIPANTS

Patients undergoing primary, elective, unilateral THA.

MAIN OUTCOME MEASURES

Failure of THA, defined as revision procedure for (1) any reason, (2) septic reason, or (3) aseptic reason after the index procedure.

RESULTS

A total of 35,140 THAs with 3.0 years of median follow-up were identified. Women constituted 57.5% of the study sample, and the mean (SD) patient age was 65.7 (11.6) years. A higher proportion of women received 28-mm femoral heads (28.2% vs 13.1%) and had metal on highly cross-linked polyethylene-bearing surfaces (60.6% vs 53.7%) than men. Men had a higher proportion of 36-mm or larger heads (55.4% vs 32.8%) and metal on metal-bearing surfaces (19.4% vs 9.6%). At 5-year follow-up, implant survival was 97.4% (95% CI, 97.2%-97.6%). Device survival for men (97.7%; 95% CI, 97.4%-98.0%) vs women (97.1%; 95% CI, 96.8%-97.4%) was significantly different (P = .01). After adjustments, the hazards ratios for women were 1.29 (95% CI, 1.11-1.51) for all-cause revision, 1.32 (95% CI, 1.10-1.58) for aseptic revision, and 1.17 (95% CI, 0.81-1.68) for septic revision.

CONCLUSIONS

After considering patient-, surgery-, surgeon-, volume-, and implant-specific risk factors, women had a 29% higher risk of implant failure than men after THA in this community-based sample.

Rapidly progressive osteoarthritis after arthroscopic labral repair in patients with hip dysplasia

Recent reports of poor clinical outcomes after arthroscopic surgery in hips with marked dysplasia have emerged. Arthroscopic resection of the hypertrophic labrum in cases of dysplasia, especially in the absence of periacetabular osteotomy (PAO), has been implicated. Some patients will refuse PAO because it is a major open procedure, opting for a less invasive arthroscopic procedure. We present the cases of 2 young adults with marked dysplasia who had rapidly progressive osteoarthrosis despite arthroscopic labral repair. Though perhaps beneficial as an isolated procedure in borderline or mild dysplasia cases, arthroscopic hip surgery, even labral repair, may best be performed with PAO in cases with more severe dysplasia. Albeit attractive as a less invasive labral-preserving surgery, arthroscopic labral repair not only may fail to provide symptomatic improvement but may compromise or preclude a later PAO if rapidly progressive osteoarthrosis ensues. Hip arthroscopy may best be performed concurrently with or after PAO but not proceeding PAO in patients requiring both procedures.

Pulmonary embolism prophylaxis in more than 30,000 total knee arthroplasty patients: is there a best choice?

Prophylaxis for pulmonary embolism (PE) prevention in total knee arthroplasty remains controversial. A joint registry evaluated venous thromboembolism prophylaxis and anesthesia impact on the incidence of PE, fatal PE, and death. Patients received mechanical prophylaxis alone or chemical with or without mechanical prophylaxis. The overall PE incidence was 0.45%; fatal PE, 0.01%; and death, 0.31%. The only significant difference in any outcome was the incidence of PE between Coumadin and mechanical prophylaxis alone. Variables associated with a higher incidence of PE were age, an American Society of Anesthesiologists score of 3 or higher, and the use of general anesthesia. Based on the findings, general anesthesia can be discouraged, and only Coumadin fared better than mechanical prophylaxis alone, whereas other forms of chemical prophylaxis revealed no significant differences.

Prophylaxis against pulmonary embolism in patients undergoing total hip arthroplasty

BACKGROUND

The optimal method of prophylaxis for the prevention of pulmonary embolism in patients undergoing total hip arthroplasty remains controversial. Guidelines appear to be contradictory. The purpose of the present study was to examine whether a best prophylactic agent exists for the prevention of postoperative pulmonary embolism and whether the type of anesthesia affects the rates of pulmonary embolism.

METHODS

From 2001 to 2008, a total joint registry from a nationwide health maintenance organization was evaluated to determine the rates of pulmonary embolism, fatal pulmonary embolism, and death among 17,595 patients without a history of venous thromboembolism who were managed with unilateral total hip arthroplasty. All patients were followed for ninety days postoperatively. Data were abstracted electronically and were validated through chart reviews. Multivariate logistic regression models were used to assess associations between the types of prophylaxis and anesthesia that were used and pulmonary embolism while adjusting for other risk factors.

RESULTS

Patients received either mechanical prophylaxis alone (N = 1533) or chemical prophylaxis (aspirin [N = 934], Coumadin [warfarin] [N = 6063], or low-molecular-weight heparin [N = 7202]) with or without mechanical prophylaxis. The rate of pulmonary embolism was 0.41% (95% confidence interval [CI], 0.32% to 0.51%) overall, 0.37% (95% CI, 0.05% to 0.70%) for mechanical prophylaxis, 0.43% (95% CI, 0.01% to 0.85%) for aspirin, 0.43% (95% CI, 0.26% to 0.59%) for Coumadin, 0.40% (95% CI, 0.26% to 0.55%) for low-molecular-weight heparin, 0.43% (95% CI, 0.28% to 0.58%) for general anesthesia, and 0.40% (95% CI, 0.28% to 0.52%) for non-general anesthesia. The mortality rate was 0.51% (95% CI, 0.40% to 1.01%) overall, 0.67% (95% CI, 0.23% to 1.34%) for mechanical prophylaxis, 0.64% (95% CI, 0.13% to 1.28%) for aspirin, 0.51% (95% CI, 0.33% to 1.02%) for Coumadin, 0.42% (95% CI, 0.27% to 0.83%) for low-molecular-weight heparin, 0.51% (95% CI, 0.35% to 0.67%) for general anesthesia, and 0.50% (95% CI, 0.36% to 0.64%) for non-general anesthesia. Regression models did not show any association between the type of prophylaxis used or the choice of anesthesia and increased odds of pulmonary embolism when adjusting for age, sex, and American Society of Anesthesiologists score.

CONCLUSIONS

No clinical differences were detected among the types of prophylaxis against venous thromboembolism or the types of anesthesia with respect to pulmonary embolism, fatal pulmonary embolism, or death on the basis of prospective collection of data by a contemporary total joint registry.

Kaiser Permanente National Total Joint Replacement Registry: aligning operations with information technology

BACKGROUND

A Total Joint Replacement Registry was developed in a large community-based practice to track implant utilization, monitor revisions and complications, identify patients during recalls and advisories, and provide feedback on clinical practices.

QUESTIONS/PURPOSES

We describe the development, implementation, and integration of this Total Joint Replacement Registry, highlighting critical steps in aligning information technology and operations.

METHODS

The primary Total Joint Replacement Registry data source consists of standardized electronic health record forms developed by consensus. The Total Joint Replacement Registry forms are integrated into the clinical workflow (preoperative, intraoperative, and postoperative) and produce a standardized progress note for electronic health record documentation. Secondary data are extracted from other electronic data sources using standard terminologies (ie, ICD-9 codes) to supplement the Total Joint Replacement Registry forms. Electronic screening algorithms are applied to identify complications, in combination with chart review validation and quality control mechanisms.

RESULTS

Three hundred fifty surgeons voluntarily contribute to the registry with 90% participation. The registry has been used for implant recalls and advisories, contract decision making, and identification of patients at risk for revisions (eg, younger patients having total knee arthroplasty). Tracking of overall survival of implants influenced clinical practice, with feedback resulting in the reduction of the number of unicompartmental and uncemented knee arthroplasties performed, usage of femoral head sizes < 28 mm, and the number of minimally invasive surgical procedures performed.

CONCLUSIONS

The Total Joint Replacement Registry has effectively aligned operations with information technology and leveraged that to enhance our ability to respond to recalls and advisories as well as improve quality of care, cost-effectiveness, and create research opportunities.

Knee replacement: epidemiology, outcomes, and trends in Southern California: 17,080 replacements from 1995 through 2004

BACKGROUND AND PURPOSE

There are limited population-based data on utilization, outcomes, and trends in total knee arthroplasty (TKA). The purpose of this study was to examine TKA utilization and short-term outcomes in a pre-paid health maintenance organization (HMO), and to determine whether rates and revision burden changed over time. We also studied whether this population is representative of the general population in California and in the United States.

METHODS

Using hospital utilization and membership databases from 1995 through 2004, we calculated incidence rates (IRs) of primary and revision TKA for every 10,000 health plan members. The demographics of the HMO population were compared to published census data from California and the United States.

RESULTS

The age and sex distributions of the study population were similar to those of the general population in California and the United States. 15,943 primary TKAs and 1,137 revision TKAs were performed during the 10-year period. Patients below the age of 65 accounted for one-third of all primary replacements and one-third of all revision replacements. IRs of primary TKAs increased from 6.3 per 10,000 in 1995 to 11.0 per 10,000 in 2004, at a rate of 5% per year (p<0.001). IRs of revision TKAs increased from 0.41 per 10,000 in 1995 to 0.74 per 10,000 in 2004 (p=0.4). Revision burden remained stable over the 10-year observation period. Surgical complications were higher in revision TKA than in primary TKA (10% vs. 7.7%; p=0.007). 90 day complication rates for primary and revision TKA including death were 0.3% and 0.6% (p=0.1) and for pulmonary embolism 0.5% and 0.4% (p=0.6). 90 day re-admission rates for primary and revision TKA including infection were 0.5% and 4.2% (p<0.001), for myocardial infarction 0.1% each, and for pneumonia 0.2% and 0.4% (p=0.08).

INTERPRETATION

The incidence of primary and revision TKA increased between 1995 and 2005. The rates of postoperative complications were low. Comparisons of the study population and the underlying general populations of interest indicate that this population can be used to predict the incidences and outcomes of TKA in the general population of California and of the United States as a whole.

An analysis of the risk of hip dislocation with a contemporary total joint registry

Dislocation rates after total hip arthroplasty in a community setting have not been well documented. We used a community based joint registry to evaluate hip dislocations that occurred within 1 year after total hip arthroplasty. We evaluated patient, implant, and technical factors associated with dislocation, including primary versus revision surgery, femoral head size (28 mm versus > or = 32 mm), operative time, surgeon volume, surgical approach, age, gender, diagnosis, American Society of Anesthesiologists (ASA) classification, and body mass index (BMI). There were 1693 primary total hip arthroplasties and 277 revision procedures performed from 2001-2003. The overall dislocation rate was 1.7% for primary total hip arthroplasties and 5.1% for revision procedures. Patients with ASA scores of 3 or 4 had a 2.3-fold dislocation increase compared with patients with scores of 1 or 2. Patients with rheumatoid arthritis had an increased risk of dislocation. The dislocation rates for primary total hip arthroplasty were 2% for 28 mm heads and 0.7% for heads > or = 32 mm. The surgeon's patient volume, surgical approach, operative time, and body mass index had no effect on dislocation.

Results of resurfacing a native patella in patients with a painful total knee arthroplasty

Between 1990 and 2003, 24 patients (28 knees) who had a total knee arthroplasty (TKA) and underwent subsequent patella resurfacing without revision of the tibial or femoral components to alleviate pain were identified. Patient charts were reviewed retrospectively and patients were interviewed after average 2.9-year follow-up (range: 1-12 years) to assess function, pain, and satisfaction with the procedure. Average patient age at revision surgery was 68 years, and the average time from the index TKA was 9.8 years. Mean Knee Society function and pain scores were 68+/-28 and 45+/-16, respectively. Average preoperative range of motion was 102 degrees (range: 65 degrees-130 degrees), and average postoperative range of motion was 106 degrees (range: 65 degrees-130 degrees). Only 52% of patients would undergo revision surgery again given their current levels of pain and function. Revision of only the patella for patients with a painful TKA who did not undergo patella resurfacing at the initial surgery provides 52% satisfactory results. Surgeons should look for other causes of pain in this patient population and reconsider their indications for not resurfacing the patella in TKA.

Outcomes in open tibia fractures: relationship between delay in treatment and infection

BACKGROUND

Emergent irrigation and debridement has been accepted as a mainstay of open fracture treatment. The purpose of this study was to evaluate the infectious outcome of open tibia fractures relative to the time from injury to operative irrigation and debridement.

METHODS

One hundred seventy-eight patients with 191 consecutive fractures were retrospectively reviewed. Of these, 103 patients with 106 fractures were available for this study, with an average follow-up of 10.23 months.

RESULTS

Results revealed 21.7% type I fractures, 43.4% type II fractures, 16.0% type IIIa fractures, 11.3% type IIIb fractures, and 7.5% type IIIc fractures. Of all fracture types, 22.6% became infected and 5.7% went on to have osteomyelitis. The average time to treatment was not significantly different in infected versus noninfected fractures across fracture types. No infection occurred when the time to surgery was within 2 hours; however, no significant increase in infection was discovered with respect to patients treated after 6 hours compared with those treated within 6 hours.

CONCLUSION

The results support the Gustilo grading system of open fractures as a significant prognostic indicator for infectious complication. We continue to support the emergent treatment of open tibia fractures.

Donor cell fate in tissue engineering for articular cartilage repair

Articular cartilage repair is a clinical challenge because of its limited intrinsic healing potential. Considerable research has focused on tissue engineering and transplantation of viable chondrogenic cells to enhance cartilage regeneration. However, the question remains: do transplanted allogenic cells survive in the repair with time? This study assessed donor cell fate after transplantation of male New Zealand White rabbit perichondrium cell and polylactic acid constructs into osteochondral defects created in the medial femoral condyles of female New Zealand White rabbits. Repair tissue was harvested at 0, 1, 2, 3, 7, and 28 days after implantation and was evaluated for cell viability and total cell number using confocal microscopic analysis. The number of donor cells in each sample was estimated using quantitative polymerase chain reaction targeting a gender-specific gene present on the Y-chromosome, the sex-determining region Y gene, and a control deoxyribonucleic acid present in male and female cell deoxyribonucleic acid, the matrix metalloproteinase-1 gene promoter. Average cell viability was found to be 87% or more at all times. Donor cells were present in repair tissue for 28 days after implantation. However, the number of donor cells declined from approximately 1 million at Time 0 to approximately 140,000 at 28 days. This decline in donor cells was accompanied by a significant influx of host cells into the repair tissue. This study shows that the sex-determining region Y gene is a valuable marker for tracking the fate of transplanted allogenic cells in tissue engineering.

Chondrogenic phenotype of perichondrium-derived chondroprogenitor cells is influenced by transforming growth factor-beta 1

Our laboratory has developed a method for the repair of osteochondral defects by implanting cultured perichondrial cells attached to a biodegradable polylactic acid scaffold. The success of this approach depends in part on the proliferative characteristics and the phenotype of the implanted cells. Transforming growth factor-beta 1 has been reported to influence these parameters in several mesenchymal-derived tissues in vitro and in vivo. The chondrocytic phenotype is marked by an enhanced expression of the collagen type-II gene. In this study, cultures grown from explants of rabbit rib perichondrium were exposed to exogenously added transforming growth factor-beta 1 at concentrations of 0.1-10 ng/ml of media. Cell proliferation and collagen gene expression were measured. The expression of types I and II collagen genes was analyzed by Northern blot and reverse transcriptase-polymerase chain reaction. The exogenous addition of transforming growth factor-beta 1 at a concentration of 0.1-10 ng/ml resulted in tritiated thymidine uptake by perichondrial cells, with optimum proliferative effects at 0.1 ng/ml. Transforming growth factor-beta 1 added at concentrations of 0.1 and 0.5 ng/ml significantly upregulated the expression of type-II collagen mRNAs. The results suggest that, when the chondrocytic phenotype is defined by markedly enhanced type-II collagen gene expression, the chondrocytic phenotype of explant cultures of perichondrium-derived cells is enhanced by the exogenous addition of transforming growth factor-beta 1.