ABSTRACT
In the present study, we developed a finite element model of the human ACL taking into account the anatomical insertion zones of the ligament, a knee passive 3D kinematics and a realistic constitutive law. This study was performed in three steps. The first step was to determine the three dimensional kinematics of the knee during a passive flexion. The second step was to quantify the mechanical properties of the human ACL. Identification process allowed to determine an elastic potential which describes the non linear elastic behavior of the ligament. This potential formulation was suitable for large strain situations. Finally the third step was to incorporate the measured kinematics, the ligament insertion zones and the identified elastic law into a three dimensional finite element model.
Different situations were then tested. Stress within the ligament was calculated for knee flexion till 70° under neutral, internal and external flexion. Anterior tibial drawer tests at 20° of flexion were also performed with the knee in neutral, internal and external rotation. As illustration, for the anterior tibial drawer tests, the hydrostatic stress field was almost comparable for the knee in neutral and external position. It was found that the hydrostatic and von Mises stresses during an anterior tibial drawer test were more important when the knee was in internal rotation.
