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Updated: Jun 19, 2026
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Engineering Platform and Experimental Protocol for Design and Evaluation of a Neurally-controlled Powered Transfemoral Prosthesis
Published on: July 22, 2014
Beyond microprocessor knees: exploring the potential of fully powered prosthetic legs
Kyle R Embry1,2,3, Chandrasekaran Jayaraman1,3, Chen Yang1,3
1Center for Bionic Medicine, Shirley Ryan AbilityLab, Chicago, IL, USA.
Journal of Neuroengineering and Rehabilitation
|June 18, 2026
Summary
This study found that powered knee and ankle prostheses offer comparable physiological effort to microprocessor knees but do not improve walking speed, symmetry, or endurance in individuals with limb loss.
Area of Science:
- Biomedical Engineering
- Rehabilitation Science
- Prosthetics and Orthotics
Background:
- Powered knee and ankle prostheses aim to replicate biological leg function by generating mechanical energy.
- Direct comparisons with microprocessor-controlled knee prostheses are scarce due to methodological limitations and small sample sizes.
Purpose of the Study:
- To compare the biomechanical, physiological, and functional outcomes of a powered knee and ankle prosthesis against a prescribed microprocessor knee in individuals with limb loss.
- To evaluate the effectiveness of powered prosthetic technology in improving gait parameters and reducing metabolic cost.
Main Methods:
- A crossover study involving twelve adults with transfemoral or knee disarticulation limb loss using microprocessor knees.
- Participants underwent assessments with both a powered knee and ankle prototype and their own prescribed prosthesis after device fitting and training.
- Key outcome measures included walking speed, swing time symmetry, metabolic energy cost, and functional endurance, analyzed using paired statistical comparisons.
Main Results:
- No significant differences in metabolic energy cost were observed between the powered and microprocessor prostheses, despite the powered device's increased weight.
- Participants exhibited slightly slower walking speeds and marginally reduced swing time symmetry with the powered prosthesis.
- The powered prosthesis compensated for its added weight but did not enhance walking speed, gait symmetry, or functional endurance.
Conclusions:
- The powered knee and ankle prosthesis demonstrated comparable physiological effort and postural control to existing microprocessor knees.
- This powered prosthesis did not yield significant improvements in walking speed, gait symmetry, or endurance compared to microprocessor knees.
- Further development of comparative testing protocols is crucial for optimizing powered prosthetic knee and ankle (PKA) design and validation for better clinical outcomes.
