A prospective review of 303 cementless universal cups with emphasis on wear as the cause of failure.

: Three hundred thirteen primary uncemented total hip arthroplasties were performed in a 20-month period using Universal cups and Taperloc stems with titanium heads. The follow-up period was 2 to 5 years and 303 cups were measured radiographically for polyethylene wear, demarcation, osteolysis, and migration. Analysis was performed clinically, radiographically, and via inspection at revision. Twenty-three cups (7.5%) had greater than 0.5 mm polyethylene wear. Eleven of these loosened radiographically (4%) and eight (3%) required revision. All cup failures showed evidence of polyethylene wear as a contributory cause of failure. The average rate of wear was 0.5 mm/yr. Thin polyethylene liners (less than 6 mm) and titanium heads were used in all failed implants both of which have been abandoned.