BIOENERGETIC COMPARISON OF A NEW ENERGY-STORING FOOT AND SACH FOOT INTRAUMATIC BELOW-KNEE VASCULAR AMPUTATIONS

In this study, the metabolic performances of a new energy-storing foot (Proteor) and of the solid-ankle cushion heel (SACH) are compared. Tw elve patients with traumatic below-knee amputations (mean age: 50.0 +/ - 19.9 years) and 12 patients with vascular below-knee amputations (me an age: 73 +/- 7 years) were studied. Oxygen uptake (VO2) was measured in all the subjects on a walkway at a self-selected velocity; only th e subjects with traumatic amputation were tested on a level treadmill (progressive speed: 2.4-4 and 6 km/h), and then in two randomized tria ls: incline (+5%) and decline walking treadmill test at 4 km/h. Vascul ar explorations were done in the vascular patients: distal pressure me asurements, pulse plethysmography, transcutaneous oxygen tension. Free walking was improved in subjects with traumatic amputation using the energy-storing foot (+6%), with a better bioenergetic efficiency (0.24 +/- 0.4mL/kg.m vs 0.22 +/- 0.04mL/kg.m). However, in subjects with va scular amputation, this foot did not produce an increased free velocit y nor an improved energy cost. During the level treadmill test, the tr aumatic amputee subjects showed a decrease of energy expenditure with the new prosthetic foot, more significant at sufficient speed (4 km/h) : 17.00 +/- 3.42 vs 14.67 +/- 2.05 mL/kg/min (p <.05). The same effect is shown during the incline (19.31 +/- 2.80 vs 16.79 +/- 2.32mL/kg/mi n-p <.02) and decline walking tests (14.13 +/- 3.64 vs 11.81 +/- 1.54m L/kg/min-p <.02). There is no significant difference in cardiocirculat ory effects between the two types of prosthetic foot. Despite a lower velocity, the subjects with vascular amputation exceed 70% of the maxi mal heart rate, with the cardiocirculatory factor being the main cause of walking restriction. The energy-storing foot should be reserved fo r active and fast walkers, whereas the SACH foot seems more suitable f or elderly patients with amputation with a slow walk. (C) 1995 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation