Released wear debris of implants causes local inflammation of the host tissue if it is in a phagocytosable size. The purpose of this study was to compare particle size, shape, and number of three different types of UHMWPE. After wear testing, particles were isolated from the serum and analyzed using SEM. The parameters ‘equivalent circle diameter’ (ECD) and ‘equivalent shape ratio’ (ESR) were determined. Most of the generated debris was sub-micron in size. Classifying the particles into size groups demonstrated a non-linear correlation between size and shape for all three types of polyethylene: small particles were more round, large particles were more elongated. Based on this relationship, the generated number of particles and their total surface area were estimated and compared with calculations based on size alone.