Outcome analysis of total knee-replacements in patients with rheumatoid arthritis versus osteoarthritis.

A total of 524 knees underwent a primary PCA knee arthroplasty between 1982 and 1989. Of these 415 suffered from osteoarthritis (OA) and 61 from rheumatoid arthritis (RA). They were analyzed for differences regarding the outcome. Neither survivorship analysis nor number or type of revisions revealed statistical differences among these two groups. The knee score rose in the OA group from a median of 28 to 89 points after 1 year and then dropped to 87 points between 54 and 118 months. In the RA group the median of the knee score rose from a preoperative value of 21 points to 90 points after 1 year but then dropped to 77 points at the most recent follow-up. This development was probably the result of general progression of the disease. Even in the RA group the rating was still "good" at the latest follow-up. Regarding the benefit of such a procedure in a polyarticular disease and its preservation over a long period of time, total knee arthroplasty can be recommended for patients with RA, and preferably the cemented version.