Clinical observation indicates that the polyethylene wear in replacement knee with metal to plastic articulation is a significant problem. The case studies (Knezevich et al., 1993) reinforce the concept that the design of the knee components is critical to minimize polyethylene wear and thus reduce the chances of subsequent failure. Many factors affect wear. They are, for example, contact surface configuration, material, surface finishing, loads, motion, temperature, lubrication, contaminants and previous use conditions. Among them, the essential factor is the contact surface configuration (Pappas, 1986). From the design viewpoint, avoiding high wear rates in a metal polyethylene articulation prosthesis is equal to avoiding a high contact stress in excess of the fatigue strength of the polyethylene. The aim of this study is to investigate the contact stress distribution on the tibial (bearing) component at different walking positions using the finite element method. Results can help to predict the wear potential of the tibial component.