Initial increased wear debris of XLPE-Al2O3 bearing in total hip arthroplasties

Introduction

Aseptic implant loosening caused by wear debris is a common reason for early implant failure after total hip replacement (THR).

Materials and methods

We prospectively studied 96 patients (110 hips), 48 men and 48 women (mean age 46.8 years, mean body mass index 26.1) who had undergone cementless THR (titanium stem, press-fit cup, Al₂O₃ ball, XLPE liner) at a mean of 17.4 months (SD 13.4).

Results

The semi-computerized evaluation of wear rate showed wear of 0.25 mm (SD 0.3) corresponding to a volume of 97.6 mm³ (SD 121.1) during the first year. It was remarkable that the annual rate of wear was significantly lower in the second year: 0.14 mm (SD 0.1), 60.0 mm³ (SD 78.7). The implant survival rate was 100%. However, two patients underwent revision surgery.

Interpretation

Good, early functionality can be achieved by a cementless THR including a modular stem and a XLPE-Al₂O₃ bearing system. The rate of wear debris for XLPE-Al₃O₂ was much higher than expected within the first year after THR. However, after the initial running-in period a significant decrease of wear was documented, suggesting a biphasic abrasion [0.38 mm (SD 0.2) within the first year vs. 0.14 mm (SD 0.1)] after the running-in-period 1 year following surgery.