Analysis of retrieved implants: crystallinity changes in ultrahigh molecular weight polyethylene.
The extent of in vivo induced structural alterations were evaluated in 13 retrieved implants ranging from two weeks' to seven years' implantation. A statistically significant difference in crystallinity was seen between weight-bearing and non-weight-bearing regions of the implants. Further, in the weight-bearing region, crystallinity was higher in components implanted for two or more years than in those implanted for less than one-half year. These results were consistent with our prior in vitro study on the effects of sterilization and aging. Taken together, the data indicate that UHMW polyethylene is not a static material but is continually dynamic changes in vivo.
D001672:Biocompatible Materials / Q000032:analysis*; D055598:Chemical Phenomena; D002621:Chemistry; D005069:Evaluation Studies as Topic; D006801:Humans; D007595:Joint Prosthesis; D008970:Molecular Weight; D011095:Polyethylenes / Q000032:analysis*; D013046:Specific Gravity; D013314:Stress, Mechanical; D013997:Time Factors
D001672:Biocompatible Materials; D011095:Polyethylenes