Comparison of ankle angle adaptations of prosthetic feet with and without adaptive ankle angle during level ground, ramp, and stair ambulations of a transtibial amputee: A pilot study

Abstract

This study aimed to investigate kinetics and kinematics of the ankle joint during level ground, ramp, and stair ambulations using different types of adaptive ankle feet (AAFs), Proprio-FootTM (Össur, IcEland), élan foot (Endolite, USA), and Echelon foot (Endolite, USA). A transtibial amputee was asked to walk on a level ground, a ramp with a 7° slope, and a stair of height 15 cm. The ankle angle and symmetry index (SI) based on the symmetry of the external work performed were measured for AAFs and ambulation. The single support time and stance phase during ambulation were higher for AAFs than the fixed ankle foot. During level ambulation, dorsiflexion increased for all AAFs. During slope ascent ambulation, dorsiflexion increased for the élan foot and Proprio-Foot™, as well as during the swing phase of the Echelon foot. During slope descent ambulation, the maximum dorsiflexion decreased for the Proprio-Foot™. During stair ascent, the élanElan foot and Proprio-Foot™ feet improved the dorsiflexion. During stair descent, all AAFs improved the dorsiflextion. Furthermore, SI increased for most of the adaptive ankle feet for all terrain conditions. These results indicate that AAFs can be used to improve the kinetics and kinematics of the ankle on the involved side.