Current Knowledge on the Effect of Technology and Sterilization on the Structure, Properties and Longevity of UHMWPE in Total Joint Replacement
Abstract
The structure and properties of UHMWPE strongly depend on the way of processing and post-processing modifications. The processing includes polymer resin preparation (microparticles about 100 urn in size) and resin consolidation (forming bulk material).
Post-processing modifications aim at increasing wear resistance and oxidation stability which are regarded as major factors involved in TJR failure. In order to maintain high purity materials for medical application, it is not allowed to use additional chemicals during the modification processes.
The only exception is the use of vitamin E, a natural stabilizer and antioxidant. Considering all the above mentioned facts, the modifications can be based on (I) ionizing radiation such as gamma rays or accelerated electrons, (II) thermal modification, (III) additional stabilization with vitamin E, and (IV) sterilization.
According to the modifications, we usually differentiate three generations of UHMWPE.