SURVIVORSHIP OF ROUGH-SURFACED THREADED ACETABULAR CUPS - 382 CONSECUTIVE PRIMARY ZWEYMULLER CUPS FOLLOWED FOR 0.2-12 YEARS

We studied prospectively 382 cementless (Zweymuller stem) and hybrid ( cemented stem) primary total hip replacements and used a cementless gr it-blasted titanium alloy threaded cup. After a median 5 (0.2-12)-year follow-up, 1 cup was exchanged, 2 cups were removed for deep sepsis, and 3 cups showed definite loosening; of these, 2 subsequently require d revision. Actuarial calculation methods indicated a 10-year survivor ship of 99% with cup retrieval for any cause (clinical failure), defin ite cup-loosening (radiographic failure), and revision for aseptic cup -loosening as endpoints, These intermediate results exceed those from smooth-surfaced screw rings and compare favorably with those from ceme nted cups and cementless, press-fit, metal-backed cups.