WEAR EFFECTS IN RETRIEVED ACETABULAR UHMW-PE CUPS

There is an increasing awareness of the clinical problems associated w ith ultra-high-molecular-weight polyethylene (UHMW-PE) wear and failur e in orthopaedics. This disadvantage is certainly promoted from the va rious oxidation process that can occur during prosthesis life. Scannin g electron microscopy, IR-spectroscopy, and X-ray-photoelectron spectr oscopy were employed to investigate the mechanism of polymer degradati on. In particular, comparison among the spectra of starting and retrie ved UHMW-PE components shows that the polymer oxidizes mainly in vivo. The data indicate that hydroxyl radicals are likely to be a major fac tor in degradation of the surface of this polymer, these groups are pr oduced in vivo during the implantation time. Several other chemical gr oups, produced in the different steps of the prosthesis life, are cont ained in the material.