JOA - 2026-03-26 - Journal Article
An Increase in the Treatment of High-Risk Total Joint Arthroplasty Patients Who Have Medicare at Teaching Hospitals.
Kistler NM, Iyer A, O'Brien D, Culler M, Aron A, Lieberman JR, Heckmann ND
Topics
Key Takeaway
High-risk TJA patients (Elixhauser Index ≥95th percentile) are concentrated at teaching hospitals at a significantly higher rate than non-teaching hospitals (7.39% vs. 6.16%, p<0.001), with teaching hospital comorbidity burden increasing while non-teaching hospitals decreased by 0.2 EI points from 2016–2023.
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Summary
This study examined whether the CJR bundled payment model has driven differential patient selection by comorbidity burden across teaching versus non-teaching hospitals using a national claims database of Medicare TJA patients from 2016–2023. High-risk patients (EI ≥95th percentile) comprised 7.39% of the teaching hospital cohort versus 6.16% at non-teaching hospitals (p<0.001), with the 99th percentile cohort showing 1.43% vs. 1.10% respectively. Over the study period, mean EI increased by 0.1 at teaching hospitals and decreased by 0.2 at non-teaching hospitals, suggesting diverging patient selection patterns since CJR implementation.
Key Limitation
The study cannot distinguish whether the increasing comorbidity burden at teaching hospitals reflects active avoidance of complex patients by non-teaching hospitals, natural referral concentration, or changes in coding practices over the ICD-10 era.
Original Abstract
INTRODUCTION
The Comprehensive Care for Joint Replacement (CJR) Medicare model may not adequately compensate for increased resource utilization in complex total joint arthroplasty (TJA) cases, raising concern for potential biased selection of healthier patients and avoidance of complex or high-comorbidity patients. This study quantified national trends among Medicare beneficiaries undergoing TJA, comparing comorbidity characteristics at teaching versus non-teaching hospitals.
METHODS
A comprehensive healthcare database was queried for adult patients (≥ 65 years) who underwent total knee (TKA) or total hip arthroplasty (THA) from 2016 to 2023. Patients who had Medicare insurance reimbursement were examined at teaching and non-teaching hospitals. The Elixhauser Comorbidity Index (EI) was determined using International Classification of Disease, Tenth Revision, and Current Procedural Terminology codes. High-risk patients were defined as EI above the 95th and 99th percentiles. Average EI was examined by year. Univariate analyses were performed to assess the impact of hospital type on the proportion of high-risk patients in each cohort.
RESULTS
Of the 686,229 patients identified with Medicare, "high-risk" patients comprised 6.67% (95th percentile) and 1.23% of their respective cohorts (99th percentile). The percentage of high-risk patients was significantly greater at teaching hospitals compared to non-teaching hospitals (95th percentile: 7.39 versus 6.16% and 99th percentile: 1.43 versus 1.10%; P <0.001 for all). There was an overall increase of 0.1 in EI for TJA patients at teaching hospitals and a decrease of 0.2 in EI at non-teaching hospitals between 2016 and 2023.
CONCLUSION
High-risk patients comprise a significantly greater proportion of the TJA population at teaching hospitals compared to non-teaching hospitals, quantifying the increased burden of a sicker, more comorbid cohort at teaching hospitals since the introduction of the CJR model in 2016. Medicare reimbursement models should incorporate stratification-based payment strategies that account for this population's increased healthcare needs, ensuring protected hospital spending and equitable TJA access for high-comorbidity patients.