Generation of Narrowly Distributed Ultra-High-Molecular-Weight Polyethylene Particles by Surface Texturing Techniques

Ultra-high-molecular-weight polyethylene (UHMWPE) wear particles have been recognized as the cause of aseptic loosening in total joint replacement. Macrophage phagocytosis of wear particles induces human biological/ physiological responses which eventually lead to bone resorption and osteolysis. However, the dependence of these reactions on the size and shape of the particles has not been elucidated and is not understood. This article describes a procedure to generate narrowly distributed UHMWPE particles of controlled size and shape through surface texturing by microfabrication. The textured surface is then used to rub against the polymer pins to produce wear particles in water. The surface texture produces elongated particles or equiaxed particles by design. The distribution of the particles, due to the surface-texture control, is quite narrow as compared with randomly produced surfaces. With this technique, we are able to generate UHMWPE wear particles of different size and shape within phagocytosable and nonphagocytosable populations for biological response studies.