Effects of loading direction on anterior cruciate ligament injury

Experimental evaluation of ACL (anterior cruciate ligament) injury was conducted on the femur-ACL-tibia complex (FATC) in the axial, lateral-medial, and posterior-anterior directions. FATC specimens were taken from 28 Japanese white rabbits sacrificed by overdosing with pentobarbital sodium. Mechanical loading tests of the FATC were conducted in various loading directions, and the rate and direction dependence of the structural properties of the FATC were discussed. The failure load of FATC was found to be large in relation to posterior-anterior loading and small in relation to lateral-medial loading, while the failure displacement showed the opposite tendency. The result indicates that ACL injury in pedestrian accidents depends on the impact direction. The results of lateral-medial shear tests showed a relatively larger toe-region, which indicates a very small increase in the load in relation to the increase in deformation, especially in the beginning part of the load-deformation curve.