Osteolysis around an uncemented cobalt chrome total hip arthroplasty.

One hundred consecutive uncemented Porous Coated Anatomic total hip arthroplasties performed in 91 patients who obtained prospective serial clinical and radiographic evaluation during a minimum 7-year followup period were studied for the occurrence, extent, and progression of localized periprosthetic bone loss (osteolysis). Periprosthetic bone loss occurred around the femoral component in 11 hips, the acetabular component in 2 hips, and both components in 2 hips during the followup interval. The bone loss was progressive in 6 hips (2 of 11 femoral cases, 2 of 2 acetabular cases, and 2 of 2 both component cases). It frequently occurred around components that showed no evidence of acetabular migration or femoral subsidence (11 of 15 cases). The average age at surgery of patients in the bone loss group was 10 years younger than the nonbone loss group (in the 100 hip cohort). Clinically, most patients with bone loss were asymptomatic, with the average Harris hip rating of 92.4 points (range, 85-99 points). With this particular device at this interval of followup (7 years), the acetabular and the proximal femoral osteolytic lesions are of greatest concern. Wear of the acetabular component was greater for cases with osteolysis than for those without osteolysis, but the difference was not significant.