Metal-on-Metal Hip Arthroplasty in Patients Thirty Years of Age or Younger

Background: Total hip arthroplasty in patients younger than thirty years of age represents a long-term challenge. As polyethylene wear secondary to a high activity level could be problematic, hard-on-hard bearings have been proposed to reduce wear. The aim of this retrospective case series was to assess the clinical and radiographic results of primary metal-on-metal total hip arthroplasty in patients thirty years of age or younger. Methods: We retrospectively studied thirty-four patients (forty-seven hips) who had undergone metal-on-metal total hip arthroplasty and analyzed the radiographic and clinical measurements after a mean duration of follow-up of 108 months (range, 62.4 to 153.6 months). The mean age of the patients at the time of surgery was twenty-five years (range, fifteen to thirty years). The diameter of the head of the femoral component was 28 mm in all hips except five, in which it was 32 mm. The metal-on-metal bearing was the same in all patients. Results: The mean Merle d'Aubigne score increased from 10.6 (range, 1 to 14) to 17.1 (range, 12 to 18). No wear was found on the latest radiograph, but osteolysis was noted in three femora and two acetabula. Two revisions were performed, one because of impingement secondary to cup malorientation and the other because of acetabular loosening with osteolysis. Kaplan-Meier analysis with revision of either component as the end point revealed a ten-year survival rate of 94.5% (95% confidence interval, 80% to 98.6%). The survival rate of the femoral stem was 100%. Conclusions: These encouraging intermediate-term results indicate that hip arthroplasty with metal-on-metal bearing components may be a suitable solution for young and active patients with hip osteoarthritis or osteonecrosis of the femoral head.