Oxidation behaviour in prosthetic UHMWPE components sterilized with high-energy radiation in the presence of oxygen

UHMWPE orthopaedic components are commonly sterilised by high-energy radiation. In the last 10 years, many studies pointed out that irradiation in air can lead to an oxidative degradation of the polymer, but the correlation between the sterilisation conditions and the amount and distribution of the oxidation products in the prosthetic components is still unclear. In the present study, a large number of never implanted, gamma sterilised prosthetic components have been analysed by using FTIR microspectroscopy and derivatisation techniques. Based on the obtained oxidation profiles, the samples were divided into three groups and a correlation between the oxidation products and their distribution and some sterilisation parameters have been proposed. Presence of oxygen, dose rate and temperature were found to play a highly relevant role in determining the whole oxidation degree and its distribution in the UHMWPE components.