Figure 1.

A multibody knee model was created that included six degree of freedom tibiofemoral and patellofemoral joints. Tibiofemoral and patellofemoral contact pressures were computed using an elastic foundation model, with local pressure calculated as a nonlinear function of the depth of penetration between articulating surfaces. To simulate walking, the knee was incorporated into a lower extremity musculoskeletal model with 44 muscles acting about the hip, knee and ankle.