Beyond microprocessor knees: exploring the potential of fully powered prosthetic legs.
Kyle R Embry, Chandrasekaran Jayaraman, Chen Yang and 11 others
PMID 42310747WHAT IT FOUND
The powered knee-ankle prototype did not give clinically meaningful walking benefits over microprocessor knees.
With 12 transfemoral users, it was slower on fastest-speed tests, less symmetrical in swing time, and less preferred, while oxygen cost was similar.
Key findings
01The powered prototype was slower than the microprocessor knee on fastest safe walking tests, but self-selected walking speed was not significantly different.
02The powered prototype did not increase oxygen cost despite added weight.
03Participants preferred the microprocessor knee over the powered prototype, especially for weight, dimensions, and adjustment.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
Only 12 participants were studied, all high-functioning K3 or K4 users, so the results may not apply to lower-functioning people with limb loss. Participants could not be blinded because the devices felt different, and they used their microprocessor knee at home while the powered prototype was only used in supervised lab sessions. The powered prototype was 3.1 kg heavier on average, and its fit required socket changes, suspension changes, and shoe lifts, so differences may reflect setup rather than powered function alone. The study tested only level-ground walking; stair ascent, inclines, and sit-to-stand were not evaluated because the prototype could not reliably perform them. The long study period and extended washout may have changed physiology, comfort, and body weight, which introduced variability.
Declared interests
The supplied text does not report funding or conflicts of interest.
The easy way to misread this
Do not conclude that powered prosthetic legs are ineffective in general. This study tested one heavier prototype in supervised level walking only, and it did not test tasks where powered legs may help, such as stairs, inclines, or sit-to-stand.