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Conventional 4-bar linkage knee mechanisms: a strength-weakness analysis
1Rehabilitation Center Het Roessingh, Enschede, The Netherlands.
Journal of Rehabilitation Research and Development
|February 1, 1995
Summary
Clinicians need biomechanical knowledge for prescribing lower limb prosthetics. A strength-weakness analysis of 4-bar linkage knee mechanisms found some knees offer stability, but energy expenditure remains a concern, highlighting a need for improved designs.
Area of Science:
- Biomechanics
- Prosthetics Engineering
- Rehabilitation Technology
Background:
- Effective lower limb prosthesis prescription requires clinicians to have relevant biomechanical knowledge.
- Limited data exists on the utility of various prosthetic knee mechanisms.
Purpose of the Study:
- To conduct a strength-weakness analysis of eight types of 4-bar linkage knee mechanisms.
- To inform clinicians about prosthetic knee functionality and guide prescription decisions.
Main Methods:
- Strength-weakness analysis of 8 distinct 4-bar linkage knee mechanisms.
- Evaluation of biomechanical factors including stability, energy expenditure, and friction during gait phases.
Main Results:
- Five of eight free-moving knees demonstrated intrinsic stability during the stance phase.
- Hip-flexion torque and energy requirements vary based on the center of rotation and axial load.
- Friction significantly impacts swing phase characteristics; current 4-bar linkage knees-with-lock offer limited advantages for walking.
Conclusions:
- Existing 4-bar linkage knee mechanisms, particularly those with locks, often require significant energy expenditure.
- There is a clear demand for a simpler prosthetic knee mechanism that provides free swing and controlled stance phase locking.