An Architecture for Direct Measurement of Transfemoral Prosthesis Gait Beyond the Gait Laboratory Setting

The work presented here details the development of a wireless instrumentation architecture for direct gait measurement in a transfemoral prosthesis. The system comprises a pair of multi-axis load cells located proximal to the ankle and knee joints of the prosthesis that provide a measure of moments and axial force above and below the prosthetic knee. The kinetic measurements are supplemented with knee kinematics measured using a modular goniometer attached lateral to the prosthetic knee and ground contact as indicated with a pneumatic sensor at the prosthetic heel. Each instrument wirelessly transmits collected data to host PCs, enabling direct gait measurements free of the constraints of a conventional gait laboratory setting. The data acquisition system was evaluated with a single subject with unilateral transfemoral amputation walking with a polycentric knee, composite energy-return foot, and daily-use socket. Experimental results were collected for the subject walking through a theater, enabling the rapid acquisition of gait data for level-ground walking and incline ascent/descent without the need for a motion-capture camera array or floor-embedded force plates.