Gailey, R, Roach K, University of Miami School of Medicine, Department of Orthopaedics, Division of Physical Therapy, Coral Gables, FL. rgailey@bellsouth.net.

PURPOSE: The functional value of prosthetic foot/ankle assemblies has long been difficult to demonstrate. As a result, clinicians have been obliged to prescribe prosthetic components founded on the conventional wisdom. The purpose of this study was to determine the contribution of different categories of prosthetic foot/ankle systems worn by transtibial amputees (TTA) to the distance walked in six minutes. SUBJECTS: A convenience sample of 136 unilateral TTA’s was divided into two groups based on age. The younger group (n=84) had an age range of 18-59 years with a mean of 42.3 ± 10.7 years and the older group (n=52) 60-100 years with a mean of 70.4 ± 8.2 years. METHODS AND MATERIALS: All subjects completed the Amputee Mobility Predictor (AMP) without the use of their prosthesis and the six-minute walk test with their existing prosthesis. Each subject’s prosthetic foot was classified as K1 SACH Foot, K2 flexible keel foot or multiaxial ankle, and K3/4 dynamic response foot. ANALYSIS: A regression analysis was performed using the following variables: age, AMP, time since amputation, K2 foot, and K3/4 foot with the K1 foot as the default foot. RESULTS: The model for both age groups combined was statistically significant F(4,127)=57.72, p<.0001, R²=.69. For the younger group both the K2 foot and the K3/4 foot were significant in the model and increased the distance walked in six-minutes beyond the K1 foot. In the older group only the K3/4 foot increase the distance walked. (See Table)

n/s= not significant

CONCLUSION: The use of K3/4 dynamic response prosthetic feet can increase the distance an amputee walks in six-minutes by about 30 percent in both younger and older transtibial amputees. These results implore the question should the baseline for prosthetic foot/ankle selection remain status quo as it has for generations or should the standard be brought forward taking advantage of technological advances that elevate the expected functional outcome for prosthetic wearers regardless of age? FUNDING SOURCE: Disabled American Veterans Charitable Trust.

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