Effects of the Ankle Function of the Prosthetic Foot on Walking Efficiency

Abstract

This research aimed to verify the influence of the function of the ankle joint of prosthetic foot on steady state gait. The index used was the mechanical energy conversion efficiency value. Gait analysis of normal subjects with simulated trans-tibial prosthesis was performed using a three-dimensional motion analysis system. A single-axis prosthetic foot was used, as it allowed for plantar flexion and dorsiflexion of the joint. The mechanical energy conversion efficiency value was calculated using COG data obtained by the system. The conditions of ankle function were compared between the first and the second phase of the stance. As a result, the rising phase, which is the first half of the stance, was greatly affected by dorsiflexion. Walking efficiency improved with increased restriction of dorsiflexion. The second phase, the descent phase, was affected by dorsiflexion and plantar flexion. However, ankle joint fixation produced the best result. In addition, a comparison of Solid Ankle Cushioned Heel (SACH) foot and energy storage and return prosthetic foot resulted in the SACH foot showing closer to normal gait. In conclusion, in the case of prosthetic walking and steady-state gait, abolishing the ankle dorsiflexion function has been suggested.