In vivo oxidation of gamma-barrier-sterilized ultra-high-molecular-weight polyethylene bearings.
gamma-Barrier packaging is shown to be effective in preventing oxidation of polyethylene during shelf storage and in addressing the problem of early fatigue failure seen in gamma-air-sterilized bearings with long shelf-storage before implantation. The series of gamma-barrier retrievals studied suggests that oxidation occurs in the body via the same mechanism as seen in gamma-air-sterilized bearings. A critical oxidation level is identified above which polyethylene bearings are susceptible to fatigue damage after sufficient cycles of use. Although critical oxidation was not reached in the majority of the retrieved gamma-barrier bearings studied, in vivo oxidation appears to follow an exponential increase with time. The result of in vivo oxidation is expected to be loss of mechanical properties, and susceptibility of polyethylene bearings to eventual fatigue failure.
Currier
Barbara H
BH
Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA.
Currier
John H
JH
Mayor
Michael B
MB
Lyford
Kimberly A
KA
Van Citters
Douglas W
DW
Collier
John P
JP
D005720:Gamma Rays; D006622:Hip Prosthesis; D006801:Humans; D007720:Knee Prosthesis; D008422:Materials Testing; D010084:Oxidation-Reduction / Q000528:radiation effects; D011095:Polyethylenes / Q000528:radiation effects*; D019064:Product Packaging; D017550:Spectroscopy, Fourier Transform Infrared; D018709:Statistics, Nonparametric; D013242:Sterilization / Q000379:methods*; D013718:Tensile Strength
D011095:Polyethylenes; C111601:ultra-high molecular weight polyethylene