Wear analysis of hip explants, dual mobility concept: Comparison of quantitative and qualitative analyses

Abstract

Total hip replacement fails mainly because of wear. It is of interest to analyse wear to be able to increase the longevity of the hip implants. One way to achieve it is to use instruments on explants but the most suitable depends on the application. This article aims at comparing several methods of surface analysis in the particular application of wear determination in a series of dual mobility explants. Wear measurement could help understand the wear mechanism only partially known. A coordinate measuring machine is used to get three-dimensional points representing the explants, then Pro/Engineer® and Matlab® are used to calculate wear. A mechanical (SOMICRONIC®) and an optical profilometer (Bruker nanoscope Wyko® NT 9100, ex. Veeco) are used to access roughness parameters. The comparisons of the two software showed similar results for wear calculation except in a few cases where differences are due to the theoretical volumes calculation. The comparison of the two profiling techniques resulted in similar results particularly for Sa and Sdr. The comparison of the results showed that wear is present for four explants; it is relevant with the observed characteristics. The mechanical profilometer showed better accuracy than the optical one which enable to conclude that it must not be neglected for that particular application, even if measurements need more time.