Simulation of contact gait in the cadaveric lower extremity using a novel below knee simulator

Research into gait characteristics has led to the creation of experimental gait simulators. The aim of this work was the development of a Contact Gait Simulation System (CGSS) to generate realistic plantar pressures for the contact phase of gait. The simulator seeks to create muscle loads which guide the foot through the entire loaded contact phase.

Two simulations, mid stance only (n=8) and full contact gait (n=7) were applied to cadaveric lower extremities disarticulated at the knee. The Achilles, extensor digitorum, and extensor hallucis longus tendons were clamped for the application of muscular loads while axial loads were applied to the proximal tibia and plantar pressures were measured. Live subjects (n=7) were recorded traversing the plantar pressure sensor, for regional (fore, mid, and hind foot) pressure comparisons.

By loading muscle tendons in proportion to live gait, the generated patterns of loading across the fore, mid and hind foot were representative of that found in live subjects. Hindfoot pressures dominated during the initial loading response, while forefoot pressures dominated during the terminal stance phase of gait. Regional trends showed strong similarity in timing and proportion to live gait.

The CGSS developed is capable of simulating live plantar pressures in the cadaveric model. Further manipulation of simulator control signals may improve accuracy, but as gait characteristically exhibits broad trends, exact agreement is not necessary.

We believe this System can be used to efficiently investigate the alterations to foot/ankle function resulting from injuries and surgical corrective procedures.