An artificial gastrocnemius for a transtibial prosthesis.

A transtibial amputee does not have a functional gastrocnemius muscle, which affects the knee as well as the ankle joint. In this investigation, we developed a transtibial prosthesis comprising an artificial gastrocnemius mechanism as well as a powered ankle-foot device. A pilot study was conducted with a bilateral transtibial amputee walking at a self-selected speed. The trial compared muscle electromyography and metabolic cost data for the amputee while using the active gastrocnemius prosthesis and a conventional Flex-Foot prosthesis. The experimental data showed that the compensation for ankle-foot and gastrocnemius function offered by the active device resulted in a reduced metabolic cost for the amputee participant.