An-Najah Staff

Knee injuries, especially those that affect the cruciate and lateral ligaments, are one of the most serious and frequent pathologies that affect the lower human extremity. Nor-mally, these injuries cause the sportsperson to retire from activity for long periods. Hence, the aim of this study is to develop a dynamic model for the lower extremity capable of estimat-ing forces, forces in the cruciate and collateral ligaments and those normal to the articular cartilage, generated in the knee. The proposed model considers a four-bar mechanism in the knee, a spherical joint in the pel-vis and a revolute one in the ankle. The four-bar mechanism is obtained by a synthesis proc-ess in a plane that best fits the relative tibiofemoral movement. The dynamic model includes the inertial properties of the femur, tibia, patella and the foot, the reaction force on the foot, and the most important muscles that affect the motion of the knee joint. Muscle forces are es-timated using an optimization technique. Forces in the ligaments and in the meniscus are es-timated from the dynamic equilibrium equations of the tibia. Results from the application of the model are presented on a real human task.