Validation of a lower limb model using 3D in vivo femoral kinematics from bibplane radiography

A mathematical model of the human pelvis-leg system with an anatomical surface-contact model of the knee, validated with non-invasive experimental measurements, has been used for the prediction of the forces transmitted by the various elements of the system. The study of tibio-femoral dynamics during stressful activities is necessary to understand the relationships between knee stability, anterior Cruciate ligament (ACL) injury and long term joint degeneration (osteoarthrosis). Assessment of the nature of interaction at the articulating surfaces of the joint is especially important. Knee stability is a dynamic, activity-dependent concept; thus, activity-specific models must be developed. Patient specific dynamic lower extremity models were developed using Computed Tomography (CT)-based knee contact surface data, and validated with high-accuracy in vivo knee kinematics from a cineradiographic method (simultaneously measured with other movement data and EMG). The goal of the study was to explicitly evaluate the 3D dynamics of an anthropometrically correct lower limb model with special attention to the knee, allowing careful assessment and prediction of knee stability during hopping for a group of patients who have undergone ACL reconstruction.