The physiological cost index of walking with an isocentric reciprocating gait orthosis among patients with T12-L1 spinal cord injury

Objective: The objective of this study was to compare the Physiological Cost Index of walking with a reciprocating gait orthosis to that of walking with bilateral knee-ankle-foot orthoses (KAFOs) by subjects with paraplegia resulting from T12-L1 spinal cord lesions. Methodology: Six chronic paraplegic subjects who had T12-L1 spinal cord lesions and who previously wore bilateral KAFOs were recruited. Each subject was fitted with an isocentric reciprocating gait orthosis (IRGO) and received a standardized training program. Subjects were then asked to walk using the two orthotic devices along a 40m rectangular pathway at a speed that was comfortable for them. The walking speed was measured using a stop watch, and a Polar Heart Rate Monitor was used to measure the heart rate of the subjects. The Physiological Cost Index (PCI) was calculated for comparison. Results: Ambulation using the IRGO (10.46+/-2.00 m/min) was significantly faster (p=0.009) than ambulation using the bilateral KAFOs (5.51+/-4.30 m/min). The PCI demonstrated when walking with the IRGO (2.85+/-0.77 beats/m) was significantly lower (p=0.0306) than that of the bilateral KAFOs (6.77+/-3.28 beats/m). Conclusion: Paraplegic patients with T12-L1 spinal cord lesions walk faster and more efficiently using the isocentric reciprocating gait orthosis as compared to using the bilateral KAFOs.