Evaluation of total hip arthroplasty devices using a total joint replacement registry

Journal Pharmacoepidemiology and Drug Safety
Authors Paxton, Elizabeth; Ake, Christopher; Inacio, Maria; Khatod, Monti; Marinac-Dabic, Danica; Sedrakyan, Art
Year Published 2012
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Abstract

PURPOSE: The purpose of this paper is to describe the infrastructure of the total joint replacement registry of a large integrated healthcare system’s and emphasize challenges associated with orthopedic device classification and evaluation.

METHODS: Using a large integrated healthcare system innovative infrastructure including electronic health record data, administrative data sources, and registry data collection, we evaluated device choice and outcomes of total hip arthroplasty (THA). Devices were classified into type of bearing surface (alternative versus traditional). Multiple imputation was used to accommodate missing data, and a logistic regression model was applied to assess the impact of patient and surgeon factors on choice of bearing surface. A Cox regression model was used to evaluate risk of aseptic revision while controlling for surgeon, site, and patient characteristics. Adjusted cumulative probability-of-event curves were created, comparing survival of alternative against traditional bearings of devices, with aseptic revision as the outcome of interest.

RESULTS: The study sample consisted of 25,377 primary THAs with an average follow-up of 2.7 years. Choice of bearing surface varied by surgeon and patient characteristics. After adjusting for patient, surgeon, and hospital covariates, results showed that the risk of aseptic revision associated with alternative bearings did not differ significantly from traditional bearing surfaces (hazard ratio = 1.33; 95% confidence interval: 0.90, 1.98).

CONCLUSIONS: Clinically rich data from a registry with linkages to electronic health records and other administrative databases improve identification of exposures, outcomes, and patient subgroups in medical device evaluation. These various data sources facilitate refined adjustment for potential confounders such as hospital, surgeon, and patient factors and ensure comprehensive device performance evaluation within registries.

Risk of revision for fixed versus mobile-bearing primary total knee replacements

Journal Journal of Bone and Joint Surgery, American Volume
Authors Namba, Robert; Inacio, Maria; Paxton, Elizabeth; Ake, Christopher; Wang, Cunlin; Gross, Thomas; Marinac-Dabic, Danica; Sedrakyan, Art
Year Published 2012
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Abstract

BACKGROUND: Mobile-bearing total knee arthroplasty prostheses were developed to reduce wear and revision rates; however, these benefits remain unproven. The purposes of this study were to compare the short-term survivorship and to determine risk factors for revision of mobile-bearing and fixed-bearing total knee replacements.

METHODS: A prospective cohort study of primary total knee arthroplasties performed from 2001 to 2009 was conducted with use of a community total joint replacement registry. Patient characteristics and procedure details were identified. Cox regression models were used. Bearing type was investigated as a risk factor for revision while adjusted for other risk factors such as age, American Society of Anesthesiologists (ASA) score, body mass index, sex, race, diagnosis, bilateral procedures, cruciate-retaining versus posterior-stabilized components, surgical approach, fixation, patellar resurfacing, hospital and surgeon volumes, and fellowship training.

RESULTS: The study cohort consisted of 47,339 total knee arthroplasties, with 62.6% of the procedures in women. Fixed bearings were used in 41,908 knees (88.5%) and mobile bearings in 4830 (10.2%). Rotating-platform designs were used in all mobile-bearing total knee arthroplasties (3112 had a Rotating-Platform Press-Fit Condylar posterior-stabilized design; 1053, a Low Contact Stress [LCS] design; and 665, a Rotating-Platform Press-Fit Condylar cruciate-retaining design). Patients who received fixed-bearing total knee arthroplasty systems were older (mean age, 68.1 years) than those who received mobile-bearing total knee arthroplasty systems (mean age, 62.2 years); the difference was significant (p < 0.001). Overall, 515 knees (1.1%) were revised for reasons other than infection. The survival rate was 97.8% (95% confidence interval [CI], 97.4% to 98.0%) at 6.7 years. The adjusted risk of aseptic revision for the LCS total knee replacements was 2.01 times (95% CI, 1.41 to 2.86) higher than that for fixed-bearing total knee replacements (p < 0.001).There was no significant revision risk for the other mobile-bearing total knee arthroplasty systems. There was no association with surgeon and hospital case volumes and the risk of revision total knee arthroplasty. CONCLUSIONS: Our study suggests the benefit of potential long-term wear reduction with the LCS implant may not be realized in a community-based setting, where a variety of surgical skills, surgical experience, and diverse patient demographic factors may affect early outcomes.

LEVEL OF EVIDENCE: Therapeutic Level II.

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

Journal JAMA Internal Medicine
Authors Inacio, Maria; Ake, Christopher; Paxton, Elizabeth; Khatod, Monti; Wang, Cunlin; Gross, Thomas; Kaczmarek, Ronald; Marinac-Dabic, Danica; Sedrakyan, Art
Year Published 2013
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Abstract

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.

Risk of revision following total hip arthroplasty: metal-on-conventional polyethylene compared with metal-on-highly cross-linked polyethylene bearing surfaces: international results from six registries

Journal Journal of Bone and Joint Surgery, American Volume
Authors Paxton, Elizabeth; Cafri, Guy; Havelin, Leif; Stea, Susanna; Pallisó, Francesc; Graves, Stephen; Hoeffel, Daniel; Sedrakyan, Are
Year Published 2014
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Abstract

The results of randomized controlled trials and systematic reviews have suggested reduced radiographic wear in highly cross-linked polyethylene compared with conventional polyethylene in primary total hip arthroplasty. However, longer-term clinical results have not been thoroughly examined, to our knowledge. The purpose of this study was to compare the risk of revision for metal-on-conventional and metal-on-highly cross-linked total hip arthroplasty bearing surfaces with use of a distributed data network of six national and regional registries (Kaiser Permanente, HealthEast, the Emilia-Romagna region in Italy, the Catalan region in Spain, Norway, and Australia). Inclusion criteria were osteoarthritis as the primary diagnosis, cementless implant fixation, and a patient age of forty-five to sixty-four years. These criteria resulted in a sample of 16,571 primary total hip arthroplasties. Multivariate meta-analysis was performed with use of linear mixed models, with survival probability as the unit of analysis. The results of a fixed-effects model suggested that there was insufficient evidence of a difference in risk of revision between bearing surfaces (hazard ratio, 1.20 [95% confidence interval, 0.80 to 1.79]; p = 0.384). Highly cross-linked polyethylene does not appear to have a reduced risk of revision in this subgroup of total hip arthroplasty patients. Arthroplasties involving highly cross-linked polyethylene do not appear to have an increased risk of revision in this subgroup of total hip arthroplasty patients.

International comparative evaluation of knee replacement with fixed or mobile non-posterior-stabilized implants

Journal Journal of Bone and Joint Surgery, American Volume
Authors Namba, Robert; Graves, Stephen; Robertsson, Otto; Furnes, Ove; Stea, Susanna; Puid-Verdié, Lluis; Hoeffel, Daniel; Cafri, Guy; Paxton, Elizabeth; Sedrakyan, Art
Year Published 2014
Link to article

Abstract

BACKGROUND: Mobile-bearing total knee prostheses were designed to reduce wear and improve implant survivorship following total knee arthroplasty. However, the benefit of mobile-bearing total knee arthroplasty remains unproven. Both mobile-bearing and fixed-bearing total knee arthroplasty implants are available in posterior-stabilized and non-posterior-stabilized designs. With the latter, the implant does not recreate the function of the posterior cruciate ligament (PCL) with a posterior-stabilizing cam mechanism. The purpose of the present study was to compare mobile-bearing, non-posterior-stabilized devices with fixed-bearing, non-posterior-stabilized devices used in total knee arthroplasty through a novel multinational study design.

METHODS: Through the use of a distributed health data network, primary total knee arthroplasties performed for osteoarthritis from 2001 to 2010 were identified from six national and regional total joint arthroplasty registries. Multivariate meta-analysis was performed with use of linear mixed models, with the primary outcome of interest being revision for any reason. Survival probabilities and their standard errors were extracted from each registry for each unique combination of the covariates.

RESULTS: A total of 319,616 patients (60% female) underwent non-posterior-stabilized total knee arthroplasty. A fixed-bearing, non-posterior-stabilized design was used in 258,190 (81%) of the knees and a mobile-bearing, non-posterior-stabilized design in 61,426 (19%) of the knees. Sixty-nine percent of the patients who received a fixed-bearing implant were over sixty-five years of age, compared with 63% of those who received a mobile-bearing implant. Mobile-bearing designs had a higher risk of revision, with a hazard ratio of 1.43 (95% confidence interval, 1.36 to 1.51; p < 0.001). CONCLUSIONS: Previous comparisons of mobile-bearing and fixed-bearing total knee arthroplasty outcomes have been inconclusive. The current study utilized an advanced, harmonized distributed analysis of six national and regional joint-replacement registries. To our knowledge, it is the largest analysis of mobile-bearing total knee arthroplasty to date. Mobile-bearing, non-posterior-stabilized designs presented a greater risk of failure than was found for fixed-bearing, non-posterior-stabilized designs. Caution should be used in the selection of the mobile-bearing non-posterior-stabilized design for total knee replacement.