A musculoskeletal model of the lower limb based on the first complete anatomical dataset available in the literature was implemented in OpenSim. The single leg model contains 5 rigid segments (pelvis, thigh, patella, shank and foot) and 163 actuators (representing 38 muscles). Internal consistency of the muscle and kinetic parameters is ensured because all measurements were performed on a single specimen. The original knee model was enhanced with the inclusion of a further wrapping surface representing the anterior part of the femoral condyle, where the quadriceps bundles can freely slide. This feature improves the performance of the model for high knee flexion angles giving moment arms of the knee extensors more similar to experimentally measured values.
The model was used to perform inverse dynamics analysis and muscle force estimation for gait activities of one of the patients included in the publicly available HIP98 database. A validation was performed comparing the numerically predicted forces with the electromyographic (EMG) activities of several muscles recorded during the same movement available in the HIP98 database. The results of this qualitative validation are encouraging with regards to using the developed model in the analysis of more complex tasks.