Wear resistance of first-generation highly cross-linked annealed polyethylene in cementless total hip arthroplasty is maintained 20 years after surgery

Abstract

Aims The aim of this study was to evaluate the performance of first-generation annealed highly cross-linked polyethylene (HXLPE) in cementless total hip arthroplasty (THA). Methods We retrospectively evaluated 29 patients (35 hips) who underwent THA between December 2000 and February 2002. The survival rate was estimated using the Kaplan-Meier method. Hip joint function was evaluated using the Japanese Orthopaedic Association (JOA) score. Two-dimensional polyethylene wear was estimated using Martell’s Hip Analysis Suite. We calculated the wear rates between years 1 and 5, 5 and 10, 10 and 15, and 15 and final follow-up. Results The mean follow-up period was 19.1 years (SD 0.6; 17.3 to 20.1). The 19-year overall survival rate with the end point of all-cause revision was 97.0% (95% confidence interval (CI) 91 to 100). The mean JOA score improved from 43.2 (SD 10.6; 30 to 76) before surgery to 90.2 (SD 6.4; 76 to 98) at the final follow-up (p < 0.001). There was no osteolysis or loosening of the acetabular or femoral components. The overall steady-state wear rate was 0.013 mm/year (SD 0.012). There was no hip with a steady-state wear rate of > 0.1 mm/year. There was no significant difference in wear rates for each period. We found no significant correlation between the wear rate and age, body weight, BMI, or cup inclination. Conclusion First-generation annealed HXLPE shows excellent wear resistance and no acceleration of wear for approximately 20 years, with low all-cause revision rates. Cite this article: Bone Joint J 2022;104-B(2):200–205.