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.

Keywords

3D Gait analysis, Conventional prosthetic ankle, Microprocessor-Controlled Prostheses, Transtibial Amputation

Conflict of interest statement

Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.