Knee arthroplasty in rheumatoid arthritis. Four- to six-year follow-up study.

A consecutive series of total condylar knee arthroplasties in patients with rheumatoid or related arthritis, with a 4-6-year follow-up period, was studied. Eighty-seven percent had an excellent or good overall result (score of 70 or more on the HSS knee rating scale). The median total score increased from 45 points before operation to 83 after operation. Sixteen complications, mostly minor, occurred in 14 patients. There were no early infections. Two prostheses were removed for deep infection, after 3 and 5 years. One patient had patellectomy for avascular necrosis. The crude prosthesis survival rate was 97%. Tibial radiolucencies were noted in 76% of cases; in 29% they were significant (2 mm or more in one or more of three zones). Two tibial components (2%) were believed to be mechanically loose, but no revisions for mechanical loosening were done. The presence of radiolucencies did not signify an inferior clinical result.