Personalized musculoskeletal models show that gait biofeedback alters knee cartilage contact mechanics in ACL-reconstructed subjects.

Abstract

Anterior cruciate ligament-reconstructed (ACLR) patients exhibit less dynamic knee loading during walking than uninjured controls, which may be harmful to the joint. Increasing the first peak vertical ground reaction force (vGRF) during walking by visual biofeedback promotes more dynamic loading. Musculoskeletal (MSK) modeling has served to simulate the resulting knee contact mechanics from this intervention, but the impact of model personalization has not been examined. Therefore, we compared the use of generic and personalized MSK models to characterize knee joint contact mechanics during the stance phase of habitual and biofeedback walking of eight ACLR subjects. The generic approach consisted of a literature-based MSK model with a 12-degree-of-freedom knee. The personalized approach incorporated magnetic resonance imaging (MRI)-based cartilage articulating surfaces and ligament insertion points of the ACLR knees. In our results, the vGRF differed between habitual and biofeedback walking, as well as the flexion angle, joint contact forces, and extensor moment between walking conditions using either generic or personalized simulation approaches. Regarding the contact pressure-based results, the personalized approach illustrated clearer differences in the cumulative contact pressure between tibiofemoral compartments (p < 0.05, effect size ES > 1), and both models showed differences between walking conditions, like in the excursion of the center of contact pressure in the lateral compartment of femur (p < 0.05, ES > 0.5) and tibia (p < 0.05, ES > 0.7). In conclusion, using a generic model may suffice for limb-level kinetic and kinematic analysis, and contact pressure-based variables from either of the modeling approaches capture changes in walking. However, validation is needed regarding joint site-specific conclusions.