A Means of Generating Polyethylene Wear Particles With Desired Size and Shape for Biological Studies of Osteolysis

Metallic and ceramic counterfaces with artificial surface textures were rubbed against ultra high molecular weight polyethylene (UHMWPE) pins in water-lubricated wear tests and the characteristics of wear debris were studied. Two types of surface textures were utilized. In the first type, an array of wedge shaped features was created on silicon wafers by microfabrication. It was found that the mean size of UHMWPE wear particles strongly depended on the length of the cutting edge of the wedge. For instance, for wedges with a cutting edge length of 55 μm, 15 μm, and 7 μm, it was found that more than 75% of wear particles had a mean length of 30–60 μm, 6–15 μm, and 4–10 μm, respectively. In the second type of textured surfaces, unidirectional patterns were created on the stainless steel discs. These unidirectional patterns consisted of long, parallel edges and grooves and were created by abrading the discs by different grits of sand papers. The length of the majority of unidirectional edges was found to be approximately equal to the dominant size of elongated wear debris. The narrowly distributed wear debris produced in this investigation can be used in the biological study of the effects of size and shape of UHMWPE wear particles in total joint replacements on osteolysis.