An LS-DYNA Model for the Investigation of the Human Knee Joint Response to Axial Tibial Loadings

Automotive accidents frequently involve fracture of the knee joints which can be related to either bone or soft tissue injuries. Previous studies show that the degree of anterior-posterior constraint of the femur bone along its longitudinal axis plays a crucial role in determining the knee-joint-fracture mechanism and internal tibial-femoral load distribution. Also, the anatomical tilt of the tibial plateau, tibial-femoral joint compression results in anterior displacement of the tibia, which has important implications in the prediction of knee injury and might lead to anterior cruciate ligament rupture. This study aimed at validating an existing finite element LS-DYNA® human knee joint model for replication of these complex failure mechanisms when the joint is subjected to tibial axial compression loads. Simulations were run with the joint at 90 ̊ flexion to investigate the effects of anterior-posterior joint constraint on the injury patterns. Comparisons between simulations findings and test outcomes from literature were compared in terms of anterior- posterior and medial displacements of the femur, proximal rotation of the tibia and tibial-femoral load distribution. The finite element model predicted similar injury patterns and internal loads resulted with cadaveric specimen testing. The validated numerical model can be integrated in a complete replication of the human lower extremity and employed in simulations of knee-bolster impacts with the human leg during car crashes. It would be used to predict leg injury patterns with the knee joint subjected to simultaneously axial loading of the femur and the tibia bones.