Association Between Race/Ethnicity and Total Joint Arthroplasty Utilization in a Universally Insured Population

Introduction: Previous studies have documented racial and ethnic disparities in total joint arthroplasty (TJA) utilization in the United States. A potential mediator of healthcare disparities is unequal access to care, and studies have suggested that disparities may be ameliorated in systems of universal access. The purpose of this study was to assess whether racial/ethnic disparities in TJA utilization persist in a universally insured population of patients enrolled in a managed healthcare system. Methods: This retrospective cohort study used data from a US integrated healthcare system (2015 to 2019). Patients aged 50 years and older with a diagnosis of hip or knee osteoarthritis were included. The outcome of interest was utilization of primary total hip arthroplasty and/or total knee arthroplasty, and the exposure of interest was race/ethnicity. Incidence rate ratios (IRRs) were modeled using multivariable Poisson regression controlling for confounders. Results: There were 99,548 patients in the hip analysis and 290,324 in the knee analysis. Overall, 10.2% of the patients were Black, 20.5% were Hispanic, 9.6% were Asian, and 59.7% were White. In the multivariable analysis, utilization of primary total hip arthroplasty was significantly lower for all minority groups including Black (IRR, 0.55, 95% confidence interval [CI], 0.52-0.57, P < 0.0001), Hispanic (IRR, 0.63, 95% CI, 0.60-0.66, P < 0.0001), and Asian (IRR, 0.64, 95% CI, 0.61-0.68, P < 0.0001). Similarly, utilization of primary total knee arthroplasty was significantly lower for all minority groups including Black (IRR, 0.52, 95% CI, 0.49-0.54, P < 0.0001), Hispanic (IRR, 0.72, 95% CI, 0.70-0.75, P < 0.0001), and Asian (IRR, 0.60, 95% CI, 0.57-0.63, P < 0.0001) (all in comparison with White as reference). Conclusions: In this study of TJA utilization in a universally insured population of patients enrolled in a managed healthcare system, disparities on the basis of race and ethnicity persisted. Additional research is required to determine the reasons for this finding and to identify interventions which could ameliorate these disparities.