ANALYTICAL STUDY ON THE KINEMATIC AND DYNAMIC BEHAVIORS OF A KNEE-JOINT

A knee model in the sagittal plane is established In this study. Speci fically, the model is used to study the effects of inertia, articular surfaces of the knee joint, and patella on the behaviors of a knee joi nt. These behaviors include the joint surface contact point, ligament forces, instantaneous center and slide/roll ratio between the femur an d tibia. Model results are compared to experimental cadaver studies av ailable in the literature, as well as between the quasi-static and dyn amic models. We found that inertia increases the sliding tendency in t he latter part of flexion, and lengthens the cruciate ligaments. Decre asing the curvature of the femur surface geometry tends to reduce the ligament forces and moves the contact points towards the anterior posi tions. The introduction of the patellar ligament in the model seems to stabilize the behaviors of the knee joint as reflected by the behavio r of the instant centers and the contact point pattern on the tibia su rface. Furthermore, we found that different magnitudes of the external load applied to the tibia do not alter the qualitative behaviors of t he knee joint. (C) 1997 Elsevier Science for IPEMB.