Comparison of the wear of aged and non-aged ultrahigh molecular weight polyethylene sterilized by gamma irradiation and by gas plasma.

The wear of ultrahigh molecular weight polyethylene in artificial joints is a major cause of long-term osteolysis and loosening. The wear rate of aged and non-aged ultrahigh molecular weight polyethylene sterilized by both gamma irradiation in air and gas plasma has been studied in simple configuration wear tests. Fourier transform infrared analysis (FTIR) showed marked oxidative degradation of the irradiated and aged material compared to the gas plasma sterilized and aged material. The wear rate of the irradiated and aged material was significantly (three times) higher than the gas plasma sterilized, gas plasma sterilized and aged, and non-sterilized materials. Alternative sterilization procedures such as gas plasma, when used instead of gamma irradiation in air, are likely to reduce the incidence of long-term osteolysis.