Abstract
This study is concerned with the mechanical properties of knee joint ligaments, which are frequently injured in car-to-pedestrian collisions. Such injury makes a lot of disabilities in actions in daily life and it is difficult to recover the original mechanical functions of ligaments. Because of the lack of knowledge of the dynamic properties of these ligaments, there are some difficulties in finite element simulations of a car-to-pedestrian accident. Thus, we performed tensile tests on the rabbit medial collateral ligament (MCL) and anterior cruciate ligament (ACL) to evaluate the strain-rate dependence of their mechanical properties. The failure stress of the MCL increased with the strain rate. The avulsion load of the MCL tibial insertion was lower than the failure load of the MCL in all conditions tested. Three types of failure patterns were observed in the femur-ACL-tibia complex. The tangent modulus and the maximum stress of the ACL complex increased with the strain rate. The strain-rate dependence of the mechanical properties of knee ligaments was evaluated quantitatively. The results are expected to be useful for discussion of the injury criteria for the knee joint and its protection.
