IMPROVED RADIOGRAPHIC SURVIVAL OF THE CHARNLEY PROSTHESIS IN RHEUMATOID-ARTHRITIS AND OSTEOARTHRITIS - RESULTS OF NEW VERSUS OLD OPERATIVE TECHNIQUES IN 402 HIPS

Two hundred one consecutive, primary, noninfected Charnley (Thackray, Leeds) hip arthroplasties, implanted from 1968 to 1985 due to adult-on set rheumatoid arthritis, were matched in pairs with respect to year o f operation, age, and sex with 201 Charnley prostheses implanted due t o osteoarthritis. The 10-year survival estimate for nonrevisions was 9 5% in the rheumatoid group and 89% in the osteoarthritic group. Using definite radiographic loosening as a determinant, the 7-year survival rate for stems increased from 80% to 96% for both groups after the int roduction of new cementing techniques, and the relative risk for stem loosening was decreased to one fifth. In the rheumatoid arthritis grou p, the 7-year radiographic socket survival increased from 87% to 96%, an increase ascribed to the overall effect of the introduction of flan ged sockets, bone-grafts in acetabular protrusion, the rejection of th e pilot hole technique, and improvements in the cement handling techni que. In the osteoarthritis group the radiographic socket survival rate at 7 years was 97% and at 10 years was 95%.