Wear of Crosslinked UHMWPE in a Hip Joint Simulator

Crosslinking has been extensively introduced to reduce the wear of UHMWPE. In this study the wear rates and wear surfaces of UHMWPE with different levels of crosslinking were compared in a hip joint simulator. The UHMWPE was either non-irradiated, gamma irradiated in air (2.5MRad), or highly crosslinked (7.5 and 10MRad). The intentionally cross-linked materials showed a significantly lower volume change compared to the non-crosslinked UHMWPE. The results of the surface topography of the acetabular cups showed that the highly crosslinked materials became smoother than the other materials as the test progressed. This would benefit the crosslinked materials in aiding lubrication. Finite wear rates have been recorded for the first time in simulator studies with highly crosslinked polyethylene. The wear rates and wear surfaces compare with those found in clinical studies.