Improved ankle-foot system for above-knee amputees.

Area of Science:

• Biomechanical Engineering
• Prosthetics and Orthotics
• Rehabilitation Science

Background:

• Above-knee amputees often experience gait deviations and reduced mobility.
• Standard prosthetic feet may not fully replicate natural ankle and foot mechanics.
• Improving prosthetic foot design is crucial for enhancing amputee function.

Purpose of the Study:

• To evaluate the effects of a modified single-axis prosthetic foot on the gait of above-knee amputees.
• To compare the performance of a modified foot with increased dorsiflexion and reduced MTP joint stiffness against a standard foot.
• To quantitatively and qualitatively assess gait parameters and user comfort.

Main Methods:

• Above-knee amputees tested prostheses with standard and modified single-axis feet, adjusting joint stiffness for optimal comfort.
• Gait analysis was performed using treadmill walking at various speeds and inclines.
• Quantitative measurements of gait cycle parameters and qualitative user feedback were collected.
• Gait data from age- and sex-matched normal subjects served as controls.

Main Results:

• Amputees reported greater comfort and easier walking on level ground and inclines with the modified foot.
• The modified foot allowed dorsiflexion matching normal subjects, but limited MTP joint flexion.
• Potential knee instability on declines and critical foot placement on stairs were noted.
• Hip movement patterns became more symmetrical but still differed from normal subjects.

Conclusions:

• The modified prosthetic foot enhances gait comfort and symmetry for above-knee amputees.
• Coupling ankle joint modifications with improved knee joint mechanisms could further enhance prosthetic gait.
• Further research is needed to address knee instability during specific activities like descending declines and stair negotiation.