Development of a 3D model of a total knee to analyze the deep knee flexion

Abstract

Most of conventional methods to evaluate the design of knee prosthesis need the assumption about joint load, contact location or so, and they usually are calculated two-dimensional simple model without considering the joint shape. Therefore we created the 3D mathematical model to analyze the knee mechanics. The features of the model are that, driven by the muscle forces, including both patellofemoral and tibiofemoral joints connected by patellar tendon, including the condition of point contact using free-form surface, outputting the muscle forces to achieve the force/moment equilibrium, and targeting the deep knee flexion to consider the contact of muscles and bones or include thigh-calf contact force. We tested the model to check the effect of tibial rotational alignment to a patellofemoral joint. As a result, we could achieve the solutions during deep knee flexion, and confirmed the medial patellofemoral contact force increased by tibial internal rotational alignment.