A new 3D kinematic model of the patello-femoral joint during knee passive motion

A complete 3D equivalent mechanism for the modelling of the knee passive motion, i.e. the motion of the joint in virtually unloaded conditions, is presented. The mechanism takes into account the relative motion of the femur and tibia and, in particular, it can also reproduce the relative motion of the patella and femur. As far as the authors are aware, this is the first 3D equivalent mechanism which can replicate the passive motion of the whole knee joint inclusive of the patella. A comparison with experimental data show the efficiency of the proposed mechanism