Improved Resistance to Wear, Delamination and Posterior Loading Fatigue Damage of Electron Beam Irradiated, Melt-Annealed, Highly Crosslinked UHMWPE Knee Inserts

摘要

Recently, a knee prosthesis containing an electron beam irradiated (58 -72 kGy, nominal dose of 65 kGy), melt-annealed, highly crosslinked UHMWPE (HXPE) tibial insert has been developed. In the present study, the wear and delamination resistance of the HXPE tibial insert and its fatigue performance under a posterior loading condition have been evaluated against its conventional gamma-sterilized UHMWPE counterpart (37kGy, in nitrogen). The test methodologies used were newly developed with the aim to evaluate this new material under severe testing conditions. In comparison to the gamma controls, the HXPE inserts: (a) wore significantly less (achieving wear reductions of 81 % and 73% over 5 and 20 million cycles, respectively); (b) exhibited significantly improved delamination resistance; and (c) exhibited significantly improved posterior loading fatigue resistance.