Patellar resurfacing reduces pain after TKA for juvenile rheumatoid arthritis.

Influence of patellar resurfacing after knee replacement and the frequency of patella infera and its relation to the postoperative appearance of the knee pain were assessed in patients with juvenile rheumatoid arthritis. Seventy-seven total knee arthroplasties using the AGC prosthesis with nonconstrained components were done on 52 patients with a mean followup of 7.3 years (range, 3-13 years). Anterior knee pain was present in 14 of 30 patients (47%) with an unreplaced patella and in two of 18 patients (11%) with patella resurfacing. The patella was replaced in 18 patients (35%) and in 23 of 77 knees (30%). Neither revision surgery of implanted patellar components nor any later resurfacing of an unreplaced patella were done during the followup. Preoperatively using the Insall-Salvati ratio, the majority of knees (54 of 77) had a low-riding patella. Patella infera occurred commonly in patients with juvenile rheumatoid arthritis. No connection between patella infera and anterior knee pain was found.