Objective: Although new treatments for rheumatoid arthritis (RA) are extremely effective in preventing disease progression, rates of total knee replacement (TKR) continue to rise. The ongoing need for TKR is problematic, especially as functional outcomes in patients with RA have been reported to be worse than in patients with osteoarthritis (OA). The purpose of this study is to assess pain, function, and quality of life 2 years after TKR in contemporary patients with RA compared with patients with OA.
Methods: Primary TKR cases enrolled between May 1, 2007 and July 1, 2010 in a single institution TKR registry were eligible for this study. Validated RA cases were compared with OA at baseline and at 2 years.
Results: We identified 4456 eligible TKR, including 136 RA. Compared with OA, RA TKR had significantly worse preoperative Western Ontario and McMaster Universities Osteoarthritis Index pain (55.9 vs 46.6, p < 0.0001) and function (58.7 vs 47.3, p < 0.0001); however, there were no differences at 2 years. Within RA, there was no difference for patients who were treated with biologic disease-modifying antirheumatic drugs versus those who did not in pain (p = 0.41) or function (p = 0.39) at 2 years. In a multivariate regression, controlling for multiple potential confounders, there was no independent association of RA with 2-year pain (p = 0.18) or function (p = 0.71). Satisfaction was high for both RA and OA.
Conclusion: Patients with RA undergoing primary TKR have excellent 2-year outcomes, comparable with OA, in spite of worse preoperative pain and function. In this contemporary cohort, RA is not an independent risk factor for poor outcomes.
Keywords: ARTHROPLASTY; DISEASE-MODIFYING ANTIRHEUMATIC DRUGS; OSTEOARTHRITIS; RHEUMATOID ARTHRITIS.