The effect of prosthetic foot stiffness on foot-ankle biomechanics and relative foot stiffness perception in people with transtibial amputation

Prosthetic feet are available in a range of stiffness categories, however, there is limited evidence to guide optimal selection during prosthetic foot prescription. The aim of this study was to determine the effect of commercial prosthetic foot stiffness category on foot-ankle biomechanics, gait symmetry, community ambulation, and relative foot stiffness perception. Participants were fit in randomized order with three consecutive stiffness categories of a commonly-prescribed prosthetic foot. Prosthetic foot roll-over shape and ankle push-off power and work were determined via data collected during walking in a motion analysis laboratory. Step activity was recorded during community use of each foot. Self-reported perception of relative foot stiffness was assessed with an ad hoc survey. Seventeen males with transtibial amputation completed the study. Prosthetic foot roll-over radius increased with increased prosthetic foot stiffness categories (p