THE CAT-CAM SOCKET AND QUADRILATERAL SOCKET - A COMPARISON OF ENERGY-COST DURING AMBULATION

Twenty unilateral trans-femoral amputees fitted with either the Contou red Adducted Trochanteric-Controlled Alignment Method (CAT-CAM) socket (n=10) or the quadrilateral (QUAD) socket (n=10), and a ''non-amputee '' control group (n=10) participated in the study. Subjects meeting th e following criteria were studied: healthy males between the ages of 1 8 and 55 years, amputation due to non-vascular pathology, an unaffecte d sound limb, at least six months use of the test prosthesis, and a mi nimal stump length of 15 cm. Subjects ambulated in two randomized tria ls separated by 20 minutes of rest at 2 assigned speeds: a pace reflec ting normal walking speed (97 m/min=2.5 mph) or a slower speed (48.5 m /min=1.25 mph). Heart rate (HR) and Oxygen uptake (VO2) measured durin g steady state walking were analyzed via two-way ANOVA. Differences am ong means were further analyzed using Tukey post hoc and simple effect s tests. Significant differences were observed between the control gro up and CAT-CAM subjects with respect to VO2 (p<0.05) and HR (p<0.01) a t the slower speed. The control group and subjects using the QUAD sock et also differed with respect to VO2 (p<0.01) and HR (p<0.01) at the s lower pace. Faster pace required more energy expenditure (p<0.01) and produced higher HR (p<0.01) than slower speeds. At faster pace, a sign ificantly higher energy expenditure in the QUAD than the CAT-CAM group was observed (p<0.01). It is concluded that ambulating at normal pace using the CAT-CAM socket design uses less energy than when using a QU AD socket design.