Researchers compared the effects of using a powered ankle-foot prosthesis to a passive-elastic energy storage and return (ESAR) prosthesis and found that people who used the powered ankle-foot prosthesis had equivalent metabolic costs to people without amputations when compared to the ESAR prosthesis. The findings also demonstrated that use of the powered prosthesis can increase symmetry during walking on uphill slopes and step-to-step transition work for level-ground walking over a range of speeds.
Ten people (six men and four women) with unilateral transtibial amputations walked 1.25 m/s-1 on a dual-belt force-measuring treadmill at 0°, ± 3°, ± 6°, and ± 9° using their own passive-elastic prosthesis and the BionX Medical Technologies BiOM T2 powered ankle-foot prosthesis. A certified prosthetist from BionX aligned the powered prosthesis for each participant.
The researchers measured metabolic rates, kinematics, and kinetics, then calculated net metabolic power, individual leg step-to-step transition work, and individual leg net work symmetry.
The net metabolic power was 5 percent lower during walking on +3° and +6° uphill slopes when subjects used the BiOM compared to their passive-elastic prosthesis. The use of the BiOM compared to a passive-elastic prosthesis did not affect individual leg step-to-step transition work but did improve individual leg net work symmetry on +6° and +9° uphill slopes, according to the study.
The open-access study was published August 29 in the Journal of the Royal Society Interface.
