A controlled clinical trial of a clinically-tuned powered ankle prosthesis in people with transtibial amputation

To determine whether there are changes in level walking performance for people using a powered ankle prosthesis that was tuned by an independent, manufacturer-certified prosthetist in accordance with device recommendations.

Intervention study with cross-over design.

Laboratory.

Convenience sample of 10 individuals with unilateral, transtibial amputation, and 10 age- and gender-matched control participants.

Powered ankle prosthesis (BiOM T2 Ankle System). Main outcome metrics: Metabolic costs of walking, preferred walking speed.

There were no significant differences in oxygen consumption (2.9% difference; P = 0.606, d = 0.26), cost of transport (~1% difference; P = 0.652, d = 0.23), or preferred walking speed (~1% difference; P = 0.147, d = 0.76) when using the powered ankle compared to unpowered prostheses. Secondary analyses of user characteristics revealed that participants who were classified as having the highest function (K4 on Medicare's 5-point scale from K0 to K4) were significantly more likely to exhibit energy cost savings than those classified as having lower function (K3; P = 0.014, d = 2.36).

Participants did not demonstrate significant improvements in energetics or preferred speed when wearing a clinically tuned powered ankle prosthesis compared to their non-powered prostheses. Prescribers of powered devices should understand that not all users will show an immediate reduction in energy expenditure.