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Effects of simulated oxidation on the in vitro wear and mechanical properties of irradiated and melted highly crosslinked UHMWPE
Author(s) -
Oral Ebru,
Neils Andrew L.,
Doshi Brinda N.,
Fu Jun,
Muratoglu Orhun K.
Publication year - 2016
Publication title -
journal of biomedical materials research part b: applied biomaterials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.665
H-Index - 108
eISSN - 1552-4981
pISSN - 1552-4973
DOI - 10.1002/jbm.b.33368
Subject(s) - materials science , irradiation , polyethylene , composite material , thermal oxidation , annealing (glass) , radical , joint arthroplasty , organic chemistry , arthroplasty , chemistry , physics , layer (electronics) , nuclear physics , medicine , surgery
Radiation crosslinked ultrahigh molecular weight polyethylene (UHMWPE) have reduced the wear rate of the bearing surface in total joint arthroplasty and the incidence of peri‐prosthetic bone loss due to wear particles. The oxidation potential afforded to the material by the trapped residual free radicals after irradiation was addressed in first generation crosslinked UHMWPEs by using thermal treatments such as annealing or melting after irradiation. Postirradiation melted crosslinked UHMWPE did not contain detectable free radicals at the time of implantation and was expected to be resistant against oxidation for the lifetime of the implants. Recent analyses of long‐term retrievals showed it was possible for irradiated and melted UHMWPEs to oxidize in vivo but studies on the effects of oxidation on these materials have been limited. In this study, we determined the effects of in vitro aging on the wear and mechanical properties of irradiated and melted UHMWPE as a function of radiation dose and found that even small amount of oxidation (oxidation index of 0.1) can have detrimental effects on its mechanical properties. There was a gradual increase in the wear rate below an oxidation index of 1 and a drastic increase thereafter. Therefore, it was shown in a simulated environment that oxidation can have detrimental effects to the clinically relevant properties of irradiated and melted UHMWPEs. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 316–322, 2016.