The Role of Sliding Distance and Cross-shear:

For a given applied compressive load across the tibio-femoral joint, wear is therefore primarily a function of the area of polyethylene under cross-shear and the total relative sliding distance between the femoral and polyethylene insert articulating surfaces. Andriacchi et al. described the significant degree of relative sliding which can occur between the femoral and tibial articulation surfaces at heel strike during gait, and the resulting influence upon wear. Reducing wear on the articulating surface of a fixed bearing polyethylene insert therefore is primarily a function of balancing the following factors: