Comparison of mechanical energy profiles of passive and active below-knee prostheses: a case study.

BACKGROUND: With the recent technological advancements of prosthetic lower limbs, there is currently a great desire to objectively evaluate existing prostheses. Using a novel biomechanical analysis, the purpose of this case study was to compare the mechanical energy profiles of anatomical and two disparate prostheses: a passive prosthesis and an active prosthesis. CASE DESCRIPTION AND METHODS: An individual with a transtibial amputation who customarily wears a passive prosthesis (Elation, Össur) and an active prosthesis (BiOM, iWalk, Inc.) and 11 healthy subjects participated in an instrumented gait analysis. The total mechanical power and work of below-knee structures during stance were quantified using a unified deformable segment power analysis. FINDINGS AND OUTCOMES: Active prosthesis generated greater peak power and total positive work than passive prosthesis and healthy anatomical limbs.
CONCLUSION: The case study will enhance future efforts to objectively evaluate prosthetic functions during gait in individuals with transtibial amputations. CLINICAL RELEVANCE: A prosthetic limb should closely replicate the mechanical energy profiles of anatomical limbs. The unified deformable (UD) analysis may be valuable to facilitate future clinical prescription and guide fine adjustments of prosthetic componentry to optimize gait outcomes. © The International Society for Prosthetics and Orthotics 2014.