An easy technique to digest and isolate UHMWPE wear particles from a hip joint simulator

The size and morphology of polyethylene wear particles isolated from in vitro tests were analysed in this study. There are some major controversies emerging in the literature that will only be resolved by careful particles analysis. Since it is difficult to identify the factors that affect size and morphology of the wear particles, the goal of this study was to compare four different polymer wear debris isolation techniques (base method and acid treatment) under identical conditions in a hip joint simulator to obtain polyethylene wear particles. We investigated achieving particulate isolation by using a different approach to the one reported in the literature that involved an easier and streamline method of particle debris isolation. The new method, compared to the previous one, used a strong base, normal centrifugation, and filtration to digest the serum constituents thus isolating the polyethylene particle debris from lubricant. In all four methods the isolation involved some or all of the following steps: density gradient separation, centrifugation or ultracentrifugation, and washing. However, a requirement for all these techniques was that the lubricant had to be devoid of organic compounds in order to effectively image and count the particle debris. The results from these studies clearly show that this new method of particle isolation is easier and more streamlined than the three methods analysed and reported in literature because it did not involve ultracentrifugation and is quicker.