A novel method of cross-linking ultra-high-molecular-weight polyethylene to improve wear, reduce oxidation, and retain mechanical properties. Recipient of the 1999 HAP Paul Award.
Increasing cross-linking has been shown in vitro and in vivo to improve markedly the wear resistance of ultra-high-molecular-weight polyethylene (UHMWPE). The reduction in the mechanical properties of polyethylene under certain methods used to produce cross-linking has been a concern, however. These reductions are known to result from the processes used to increase the cross-link density and could affect the device performance in vivo. We present a novel method of increasing the cross-link density of UHMWPE in which UHMWPE is irradiated in air at an elevated temperature with a high-dose-rate electron beam and subsequently is melt-annealed. This treatment improves markedly the wear resistance of the polymer as tested in a hip simulator, while maintaining the mechanical properties of the material within national and international standards. This method leads to the absence of detectable free radicals in the polymer and, as a result, excellent resistance to oxidation of the polymer.
Muratoglu
O K
OK
Orthopaedic Biomechanics and Biomaterials Laboratory, Massachusetts General Hospital, GRJ 1206, Boston, MA 02114, USA..
Bragdon
C R
CR
O'Connor
D O
DO
Jasty
M
M
Harris
W H
WH
D001672:Biocompatible Materials / Q000737:chemistry* / Q000528:radiation effects; D003198:Computer Simulation; D005609:Free Radicals / Q000737:chemistry; D006622:Hip Prosthesis / Q000592:standards; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D010084:Oxidation-Reduction; D011095:Polyethylenes / Q000737:chemistry* / Q000528:radiation effects; D011474:Prosthesis Design; D013499:Surface Properties
D001672:Biocompatible Materials; D005609:Free Radicals; D011095:Polyethylenes