Effects of extended powered knee prosthesis stance time via visual feedback on gait symmetry of individuals with unilateral amputation: a preliminary study.
Andrea Brandt, William Riddick, Jonathan Stallrich and 2 others
PMID 31511010WHAT IT FOUND
Watching a target for stance time helped five people with lower-limb amputation walk more symmetrically on a treadmill right away.
The powered knee did not clearly beat their prescribed knee, and higher targets felt harder.
Key findings
01During treadmill walking, visual feedback targeting longer prosthetic stance time increased stance time on both limbs and improved stance-time symmetry; with the powered prosthesis, the highest target showed 9% greater prosthetic stance time, 4% greater intact stance time, and 36% better stance-time symmetry than no feedback.
02During treadmill walking with the powered prosthesis, the highest feedback target increased prosthesis-side peak propulsion by 22% and improved propulsion symmetry by 47% compared with no feedback.
03Participants could hit the targets with similar accuracy across devices and feedback levels, but they rated walking as harder as the feedback target became longer.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
Only five people were studied, and Subject 5 was excluded from the powered-versus-passive device comparison, so the findings are preliminary and may not represent the wider amputee population. The testing was short and laboratory-based, with brief practice and 1.5-minute treadmill trials, so it does not show whether the effect lasts during daily walking or after long-term training. Participants differed in amputation level, cause, time since amputation, prescribed prosthesis, walking speed, and prior physical therapy, and the powered prosthesis settings were tuned individually. The powered knee prosthesis did not have a powered ankle, which may limit the level of symmetry that can be achieved. Device comparisons took place across separate testing days after limited familiarisation with the powered prosthesis, which may confound the powered-versus-passive results. Walking speed can influence asymmetry, and feedback-level comparisons were made within the same speed, while device comparisons involved each person's self-selected speed for that device.
Declared interests
The supplied text states that funding came from the National Science Foundation and the National Institute of Health. It does not provide an author conflict-of-interest declaration beyond this funding statement.
The easy way to misread this
Do not conclude that a powered knee prosthesis or visual-feedback training has proven clinical benefit. The study had only five participants, Subject 5 was excluded from device comparisons, and the powered-versus-passive comparisons were not significant for stance time, propulsion symmetry, or hip power.