Multicenter study of unicompartmental knee revision. PCA, Marmor, and St Georg compared in 3,777 cases of arthrosis.

The prospective Swedish Knee Arthroplasty Project contained 772 PCA, 1564 Marmor and 1441 St Georg unicompartment prostheses, implanted for gonarthrosis during the period December 1983-July 1990. Follow-up was performed in September 1991. There was a significant difference in the cumulative revision rate after only 2 years, increasing to 15 percent for the PCA, compared with 5-7 percent for the two other types. The difference between PCA and Marmor/St Georg was loosening of the femoral component. Major polyethylene wear was noted in a quarter of the revised PCA tibial components. The wear pattern of Marmor/St Georg was not analyzed in this study.