Comparative survival of uncemented acetabular components following primary total hip arthroplasty.

BACKGROUND: Since their initial introduction in the early 1980s, uncemented acetabular components have become the preferred implant type for the majority of hip arthroplasties performed in the United States. The purpose of the present study was to compare differences in the survival of uncemented acetabular components following primary total hip arthroplasty.

METHODS: The study population included 7989 patients who had undergone 9584 primary total hip arthroplasties with twenty different types of uncemented acetabular components at the Mayo Clinic from January 1984 to December 2004. The overall rate of survival as well as the rate of survival free of revision for specific reasons (aseptic loosening, wear, osteolysis) were compared among the different components using age and sex-adjusted Cox proportional hazards regression models.

RESULTS: The risk of acetabular cup revision was significantly higher for beaded and hydroxyapatite-coated designs as compared with titanium wire mesh designs. Cross-linked polyethylene performed better than conventional polyethylene, but this finding did not reach significance. Elevated liners were associated with a significantly higher risk of cup revision due to aseptic loosening.

CONCLUSIONS: There are significant differences in the long-term survival of different types of uncemented acetabular components following total hip arthroplasty. The increased risk of revisions in the second decade after the initial total hip arthroplasty is a concern and is largely due to a steady increase in revisions because of polyethylene wear, osteolysis, and component loosening more than ten years after the time of the index arthroplasty.