Racial Variation in Total Knee Replacement in a Diverse Nationwide Clinical Trial.

OBJECTIVE: Racial variation in total knee replacement (TKR) utilization in the United States has been reported in administrative database studies. We investigated racial variation in TKR procedures in a diverse cohort with severe knee pain followed in an ongoing clinical trial.

METHODS: VITAL (VITamin D and OmegA-3 TriaL) is a nationwide, randomized controlled trial of 25,874 adults, 20% of whom are black. We identified a subgroup highly likely to have knee osteoarthritis based on severity of knee pain, physician-diagnosed knee osteoarthritis, and inability to walk 2 to 3 blocks without pain. Participants completed a modified Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) at baseline and self-reported incident TKR annually in follow-up. Using Cox regression, we analyzed the association of black versus white race with TKR, adjusting for demographic and socioeconomic characteristics, comorbidities, and WOMAC pain and function.

RESULTS: Among 1070 participants who met the inclusion criteria, black participants reported worse baseline WOMAC pain (45 vs. 32, P < 0.001) and worse function (45 vs. 32, P < 0.001). During a median of 3.6 years (interquartile range, 3.2, 3.8 years) of follow-up, TKRs were reported by 180 participants. Black participants were less likely to undergo TKR (11% vs. 19%). After adjustment, the hazard ratio for TKR for black versus white participants was 0.51 (95% confidence interval, 0.32-0.81). Lower use of TKR among black participants was observed across all levels of income and education.

CONCLUSIONS: Despite worse baseline knee pain and function, black participants had much lower adjusted risk of having TKR than white participants, demonstrating persistent racial disparity in TKR utilization.