The approach, aimed at quantifying the failure risk in highly crosslinked ultrahigh molecular weight polyethylene (UHMWPE) components for TKA was described. The nonconforming contact geometries of a TKA during flexion were represented using a cylinder-on-flat configuration. The approach incorporated the hybrid constitutive model (HM) which was more accurate than the isotropic plasticity model in simulating large deformation behavior leading up to failure. Four UHMWPE materials were investigated, unirradiated, sterilized, 100kGy crosslinked and annealed at 110°C, and 100 kGy crosslinked and remelted at 150°C. The HM model predcited peak residual stresses that were markedly smaller than those predicted using the isotropic plasticity model.