Use of a powered ankle–foot prosthesis reduces the metabolic cost of uphill walking and improves leg work symmetry in people with transtibial amputations

Abstract

People with transtibial amputations (TTAs) who use a powered ankle–foot prosthesis have equivalent metabolic costs and step-to-step transition work for level-ground walking over a range of speeds compared to non-amputees. The effects of using a powered compared to passive-elastic prosthesis for sloped walking are unknown. We sought to understand how the use of passive-elastic compared to powered ankle–foot prostheses affect metabolic cost and step-to-step transition work during sloped walking. Ten people (six M, four F) with TTAs walked 1.25 m s21 at 08, +38, +68 and +98 using their own passive-elastic prosthesis and the BiOM powered ankle–foot prosthesis, while we measured metabolic rates, kinematics and kinetics. We calculated net metabolic power, individual leg step-to-step transition work and individual leg net work symmetry. The net metabolic power was 5% lower during walking on þ38 and þ68 uphill slopes when subjects used the BiOM compared to their passive-elastic prosthesis (p, 0.05). The use of the BiOM compared to a passive-elastic prosthesis did not affect individual leg step-to-step transition work (p . 0.05), but did improve individual leg net work symmetry on þ68 and þ98 uphill slopes (p, 0.01). People with TTAs who use a powered ankle–foot prosthesis have the potential to reduce metabolic costs and increase symmetry during walking on uphill slopes.