The influence of traumatic transfemoral amputation on metabolic cost across walking speeds

Background: Recent literature indicates equivalent costs of walking can be achieved after a transtibial amputation when the individual is young, active, and/or has extensive access to rehabilitative care. It is unknown if a similar cohort with transfemoral amputation can also achieve lower metabolic costs of walking than previously reported. Objective: Compare metabolic cost in individuals with a transfemoral amputation to controls and to the literature across a range of walking speeds. Study design: Cross-sectional. Methods: A total of 14 individuals with a unilateral transfemoral amputation (27 ± 5 years, N = 4 mechanical knee, N = 10 microprocessor knee) and 14 able-bodied controls (26 ± 6 years) walked at self-selected and four standardized speeds. Heart rate, metabolic rate (mL O₂/kg/min), metabolic cost (mL O₂/kg/m), and rating of perceived exertion were calculated. Results: Self-selected speed was 8.6% slower in the transfemoral amputation group (p = 0.031). Across standardized speeds, both metabolic rate and metabolic cost ranged from 44%–47% greater in the transfemoral amputation group (p < 0.001), heart rate was 24%–33% greater (p < 0.001), and perceived exertion was 24%–35% greater (p < 0.009). Conclusion: Although the transfemoral amputation group was relatively young, physically fit, and had extensive access to rehabilitative care, the metabolic cost of walking fell within the ranges of the literature on older or presumably less fit individuals with transfemoral amputation. Clinical relevance: Developments in prosthetic technology and/or rehabilitative care may be warranted and may reduce the metabolic cost of walking in individuals with a transfemoral amputation.