Influence of demographic and technical variables on the incidence of osteolysis in charnley primary low-friction hip arthroplasty

The influence of demographic and technical variables on the incidence of osteolysis in Charnley primary low-friction arthroplasty was investigated. Demographic variables included age, gender, diagnosis, and Charnley joint class. Technical variables included the design of acetabular and femoral components, subchondral plate retention versus removal, and cementing techniques. We analyzed 633 hips (in 494 patients) implanted by a single surgeon between 1970 and 1984 using Kaplan-Meier survival graphs. Radiographically determined osteolysis was defined as the end point. The incidence of osteolysis at 5 years was 2% (confidence interval [CI] ± 0.5%); at 10 years, 8% (CI ± 1.6%); at 15 years, 15% (CI ± 2.2%); and at 20 years, 17% (CI ± 3.5%). Younger patients (age < 65 years) and men were both found to have a significantly increased incidence of osteolysis (P<.05). No significant association with osteolysis was found for the other demographic and technical variables investigated. Osteolysis predates loosening and failure of hip arthroplasty. Regular assessment with the goal of earlier identification, especially in higher risk younger and male patients, is important to avoid excessive bone loss and technical difficulties in revision surgery.