Marmor modular knee plateau positioning and prosthesis survival in 55 knees with rheumatoid arthritis.

In a long-term follow-up of 55 Marmor knee arthroplasties in patients with rheumatoid arthritis operated on between 1975 and 1977, the radiologically visible indicator wire was used to identify the position of the tibial components. The survival rate of the prostheses at 15 years was 0.71, and the revisions were evenly distributed over the observation period of 16 years. No significant relationship was found between the slope of the tibial components postoperatively and the survival of the prostheses. However, a postoperative valgus angle of the leg of 3 deg or more tended to increase the risk of revision (RH = 2.7, 95% CL = 0.8-8.9). The patient's sex, affected side or weight did not influence prosthesis survival.