Effectiveness of a novel microprocessor-controlled prosthetic ankle compared with conventional and microprocessor-controlled prosthetic ankles in individuals with unilateral transtibial amputation: A multicentre randomised crossover study.

BACKGROUND: Microprocessor-controlled prosthetic ankles have been developed to improve gait biomechanics in individuals with transtibial amputation; however, comparative biomechanical evidence across devices with different functional mechanisms remains limited. This study evaluated the biomechanical and metabolic effects of a newly developed motor-driven microprocessor-controlled ankle, RoFT® (MPA-2), compared with each participant's everyday conventional prosthetic ankle (CPA) and a commercially available microprocessor-controlled ankle, Meridium® (MPA-1). METHODS: Eighteen individuals with unilateral transtibial amputation participated in this multicentre study. Each participant's everyday CPA was assessed as the baseline condition, after which MPA-1 and MPA-2 were evaluated in a randomised crossover sequence. Each MPA was used for a two-week adaptation period, with a two-week washout period between MPA conditions. Three-dimensional gait analysis was performed to evaluate spatiotemporal, kinematic, kinetic, ground reaction force and symmetry index parameters. Cardiopulmonary exercise testing during treadmill walking assessed metabolic energy expenditure. RESULTS: MPA-2 produced greater amputated-limb ankle range of motion and peak positive ankle power, the primary outcome, than CPA and MPA-1. Propulsion-related anterior-posterior ground reaction force parameters were higher with MPA-2 than with MPA-1 but did not differ significantly from CPA. Intact-limb first peak vertical ground reaction force was lower with MPA-2 than with CPA. MPA-2 improved ankle power-generation symmetry, whereas propulsion impulse symmetry was poorer with MPA-1. Metabolic energy expenditure did not differ significantly among prosthetic conditions. SIGNIFICANCE: The RoFT® MPA showed favourable biomechanical effects on ankle power, propulsion-related mechanics, and selected measures of interlimb symmetry, although these biomechanical changes were not accompanied by reduced metabolic energy expenditure.