Wear rates of ceramic-on-ceramic bearing surfaces in total hip implants: a 12-year follow-up study

A retrospective clinical and radiographic analysis was performed on 58 patients (60 hips; mean age at time of surgery, 45.2 years) at a minimum of 10-year follow-up (mean, 12.7 years) after total hip replacement using a ceramic-on-ceramic hearing total hip implant (Autophor, Smith and Nephew, Memphis, TN). Mean wear rate at final follow-up was 0.21 mim, averaging 0.016 mm/y. There were no cases of periprosthetic osteolysis in the acetabuulum or femur. For the unrevised components, there were 3 (5%) cases of protrusio acetabuli and 4 (7%) cases of acetabular component loosening. On the femoral side, 78.3% had distal pedestal formation, and 83% had greater than 2 mm implant-bone radiolucencies in more than 5 Gruen zones as a result of gross motion of the stem. Despite radiographic evidence of implant loosening, this hard bearing articulation functioned well in vivo for more than 12 years with remarkably low wear--approximately one tenth the rate reported for metal-on-polyethylene total hip bearings.