Comprehensive analysis of energy storing prosthetic feet: Flex Foot and Seattle Foot Versus Standard SACH foot.

This study compared the mechanical and biomechanical functions, metabolic demand, and shock absorption of two dynamic elastic response (DER) prosthetic foot designs with the SACH foot. Nine individuals who had undergone unilateral below knee amputation were studied. Mechanical properties of the feet were related to gait biomechanics. Forefoot compliance is greatest for the Flex Foot and least for the SACH foot, hence, Flex Foot demonstrates (1) the longest midstance phase, (2) the greatest ankle angle range, and (3) greater forward movement of the center of pressure. There was some evidence that the DER feet produced a better push-off. However, neither the self-selected walking speed nor the metabolic rate or efficiency over a spectrum of walking speeds (73 to 120m/min) and running speeds (140 to 200m/min) was significantly different. Because no energy savings resulted for the DER feet, the release of stored energy in the flexible feet may not occur at the proper time to assist in ambulation as a result of the natural frequency of oscillation.

Comprehensive analysis of dynamic elastic response feet: Seattle Ankle/Lite Foot versus SACH foot.

This study evaluated biomechanical and metabolic performance differences between two prosthetic foot designs in light of their mechanical properties. Ten unilateral below-knee amputee subjects, at least 1 year after amputation, capable of walking and running, were studied. Differences in heel and forefoot compliance explained differences in gait events and alignment. Increased efficiency of pushoff in the Seattle Ankle/Lite Foot exists as evidenced by the decrease loading on the opposite limb during double support and a less shortened step length on the sound side compared to the SACH foot. The natural frequency of oscillation for the prosthetic feet was determined to be too high to provide energy storage and release synchronized with kinematic requirements because neither metabolic cost savings nor differences in metabolic efficiency were found. Comfortable walking speed and the nadir of metabolic rate and efficiency are not different. Via accelerometer measurement, it was found that the more compliant and lossy SACH foot heel was less likely to transmit high frequency vibration.

Influence of cryotherapy on spasticity at the human ankle.

The application of cryotherapy to temporarily reduce spasticity is a widespread clinical practice. A method of quantifying spasticity, based on viscoelastic stiffness measurements at the ankle, was applied to objectively determine the efficacy of cryotherapy in reducing spasticity of the calf. Baseline, cryotherapy and one-hour postcryotherapy measurements of spasticity were performed in 25 subjects with clinical signs of spasticity secondary to traumatic brain injury, spinal cord injury, and stroke. A statistically significant reduction in spasticity occurred during cryotherapy. Postcryotherapy results were equivocal, although there was a tendency for diminished spasticity relative to the baseline measurement. Two subjects showed a clear aggravation of spasticity following cryotherapy, thus leading to the conclusion that dichotomous results are possible.