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-onset rheumatoid arthritis, were matched in pairs with respect to year of operation, age, and sex with 201 Charnley prostheses implanted due to osteoarthritis. The 10-year survival estimate for nonrevisions was 95% 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 introduction of new cementing techniques, and the relative risk for stem loosening was decreased to one fifth. In the rheumatoid arthritis group, the 7-year radiographic socket survival increased from 87% to 96%, an increase ascribed to the overall effect of the introduction of flanged sockets, bone-grafts in acetabular protrusion, the rejection of the pilot hole technique, and improvements in the cement handling technique. In the osteoarthritis group the radiographic socket survival rate at 7 years was 97% and at 10 years was 95%.