Administrative database studies have found racial differences in total knee replacement (TKR) usage in the United States. For ongoing clinical research, the researchers explored ethnic variance in TKR operations in a heterogeneous sample of patients with significant knee pain. VITAL (VITamin D and OmegA-3 Experiment) was a randomized controlled trial including 25,874 people, 20% of whom were black. Based on the intensity of knee discomfort, physician-diagnosed knee osteoarthritis, and inability to walk 2 to 3 blocks without pain, they identified a subgroup that was extremely likely to have knee osteoarthritis. At baseline, participants completed a modified Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and in follow-up, they self-reported the incident TKR. They used Cox regression to examine the relationship of black vs white race with TKR while controlling for demographic and socioeconomic variables, comorbidities, and WOMAC pain and function scores.

Black participants had worse baseline WOMAC pain (45 vs. 32, P< 0.001) and function (45 vs. 32, P< 0.001) among the 1,070 participants who met the inclusion criteria. TKRs were reported by 180 patients across a median of 3.6 years (interquartile range, 3.2, 3.8 years) of follow-up. Participants who were black were less likely to have TKR (11% vs. 19% ). After correction, the hazard ratio for TKR for black vs white individuals was 0.51 (95% CI, 0.32–0.81). TKR use was lower among black participants across all income and education levels. Despite having greater baseline knee pain and function, black individuals had a considerably lower adjusted chance of getting TKR than white participants, showing a continuing racial difference in TKR usage.