Comparative Outcomes of Total Knee Arthroplasty in Patients With Osteoarthritis vs With Rheumatoid Arthritis: A Meta-Analysis.

Abstract

Background: Total knee arthroplasty (TKA) is a well-established treatment for end-stage knee disease secondary to osteoarthritis (OA) or rheumatoid arthritis (RA). Although both conditions benefit from surgical intervention, they represent distinct patient phenotypes with differences in systemic inflammation, immunosuppression, comorbidity burden, and medical therapy, which may influence postoperative outcomes. This meta-analysis aimed to compare functional outcomes, implant-related complications, systemic adverse events, and infections between OA and RA patients following TKA.

Methods: A comprehensive literature search was conducted in PubMed, Scopus, Cochrane Library, and Google Scholar from database inception through September 2025. Eligible studies included randomized controlled trials, prospective and retrospective cohort studies, and registry-based analyses directly comparing outcomes of TKA in OA versus RA patients. Subgroup analyses included sex-matched and registry-based analyses.

Results: Thirty-five studies including over 7.0 million OA and 220,000 RA patients were analyzed. Functional outcomes (Knee Society Score (KSS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Hospital for Special Surgery (HSS) Expectation score, and visual analogue scale (VAS) pain) showed no significant differences between groups. Quality-of-life measures statistically favored OA, with higher Short Form-36 (SF-36) physical component summary (PCS) (MD = 0.46; p < 0.00001) and mental component summary (MCS) scores (MD = 0.32; p = 0.01), although these differences were of limited clinical significance. RA patients had higher risks of periprosthetic infection (RR = 0.37; 95% CI 0.26-0.54; p < 0.00001), prosthetic loosening (RR = 0.29; p = 0.02), wound complications (RR = 1.28; p = 0.01), and chronic pain (RR = 1.91; p = 0.02), whereas OA patients had higher risks of deep vein thrombosis (RR = 1.22; p = 0.02), pulmonary embolism (RR = 1.21; p < 0.00001), respiratory (RR = 1.68; p = 0.04), renal (RR = 1.27; p = 0.007), and gastrointestinal complications (RR = 1.36; p < 0.00001). Sex-matched analyses attenuated most differences, although periprosthetic infection remained higher in RA (RR = 0.49; p = 0.0001). Registry-based analyses confirmed higher risks of periprosthetic infection (RR = 0.35; p = 0.007) and prosthetic loosening (RR = 0.26; p = 0.05) in RA, with comparable revision rates, mortality, and functional outcomes.

Conclusion: TKA provides comparable functional outcomes and implant survivorship in OA and RA patients. However, distinct complication profiles reflect disease-specific biological and comorbidity factors rather than differences in surgical efficacy. These findings support individualized perioperative risk stratification rather than expectations of differential functional benefit.

Supplementary information: The online version contains supplementary material available at https://doi.org/10.1007/s43465-026-01803-4.