A Quasi-Passive Biarticular Prosthesis and Novel Musculoskeletal Model for Transtibial Amputees

Abstract

University of Washington Abstract A Quasi-Passive Biarticular Prosthesis and Novel Musculoskeletal Model for Transtibial Amputees Andrea Willson Chair of the Supervisory Committee: Patrick Aubin, Ph.D. Affiliate Assistant Professor Mechanical Engineering Transtibial amputees alter their gait pattern to compensate for prosthetic feet with limited functionality. The lack of biarticular actuation is one prominent example of the differences between commercially available prosthetic feet and the intact human lower limb. A novel biarticular prosthesis (BP) with a quasi-passive clutched spring mechanism to improve transtibial amputee gait was designed and evaluated. An open-sourced amputee musculoskeletal model was developed, validated, and utilized to evaluate how the BP affected gait. Seven transtibial amputee subjects walked on a treadmill using their prescribed prosthesis and then wearing the BP under different spring configurations and with biofeedback. Motion capture and ground reaction force data were collected, processed, and then OpenSim was used to perform inverse kinematics, inverse dynamics, and static muscle force optimization. Mechanically the BP performed as expected with the biarticular spring replicating the function of the gastrocnemius, albeit at torque levels much lower than biological. The BP had no significant effect on gait symmetry nor total muscle force. The developed open sourced musculoskeletal model is a valuable community resource that will aid future studies of amputee gait.