The influence of powered prostheses on user perspectives, metabolics, and activity: a randomized crossover trial.
Jay Kim, Jeffrey Wensman, Natalie Colabianchi and 1 others
PMID 33726802WHAT IT FOUND
The powered prosthesis did not significantly improve metabolic cost, daily step counts, walking speed, or overall mobility perception compared to the unpowered device.
Individual responses varied widely, with some users preferring the powered device and others finding it harder to walk with.
Key findings
01There was no group difference in metabolic cost of transport between the powered and unpowered prostheses.
02Daily step counts and walking speeds in daily life did not differ significantly between the two prostheses.
03Participants did not show a statistically significant preference for the powered prosthesis over the unpowered one.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The study had a very small sample size (n=10), which increases the likelihood of missing true effects (type II errors). The cohort was predominantly male and mostly classified as K3 (limited ambulators), which may not generalize to K4 (high-functioning) users or women. Weather conditions and lifestyle factors (e.g., retirement) likely influenced daily activity levels, confounding the ability to attribute changes solely to the prosthesis. Acclimation time was fixed (one week), but the study could not control how much participants actually used the device during that period, leading to varied levels of adaptation. Data collection relied on sensors that could not distinguish steps taken with the powered device turned off or with a dead battery.
Declared interests
Funded by the U.S. Department of Defense. No other conflicts of interest were reported.
The easy way to misread this
Do not conclude that powered prostheses are ineffective for all users. The null group-level findings mask significant individual variability, where some participants experienced clear metabolic or functional benefits while others did not. A single patient's response may differ substantially from the group average.