IN-VIVO UHMWPE BIODEGRADATION OF RETRIEVED PROSTHESIS

Sixty-two ultra high molecular weight polyethylene prosthetic componen ts (PEs) (31 tibial plateaux and 31 cups), sterilised by gamma rays or ethylene oxide (EtO), were retrieved after 1-12 years depending on di fferent medical reasons and were studied by FTIR spectroscopy with der ivatisation of oxidised species. Esters, acids and hydroperoxides were found under the surface of the EtO sterilised PEs up to 2 mm depth. T he behaviour of gamma ray sterilised PEs is more complex due to the ox idation following the sterilisation process. Ester and acid formation might arise from the diffusion of components of synuvial liquid or fro m the oxidation process, whereas hydroperoxide formation is thought to be due to the oxidation. Abrasion and delamination process is discuss ed considering the topological distribution of degradation products. ( C) 1998 Elsevier Science Ltd. All rights reserved