(Kiosk 6) The Impact of Removable Cast Walker Design on Energetic Costs of Walking

Background and/or Objectives: Analyze energetic costs of removable cast walkers (RCWs) while walking. Minimizing RCW effects on energy expenditure can increase compliance and healing performance.

Design: Participant height, weight, and leg length were measured. Standardized lab shoes were used and walking speed was established based on leg length. Oxycon metabolic system was calibrated before each trial, and measured volumetric consumption of oxygen (VO₂). Participants sat until metabolism reached 3-4 mL/kg*min (resting levels). Participants stood for 2 minutes, followed by treadmill walking for 6 minutes. Participants started with a control, no RCW condition. Participants trialed RCW conditions in random order.

Setting : CLEAR lab at Rosalind Franklin University.

Participants : 14 young-adults (ages 22-32) without gait abnormalities.

Interventions: 1. Knee-high RCW without contralateral lift, 2. Knee-high RCW with contralateral lift, 3. Ankle-high RCW without contralateral lift, 4. Ankle-high RCW with contralateral lift.

Main Outcome Measures: Metabolic rate was calculated during last 2 minutes of walking using Brockway equation, as a difference from standing rate, normalized by the participant’s mass. One-way ANOVA was used to determine significant differences between the five conditions.

Results: Significant increases in metabolic rate observed across 4 RCW conditions compared to control. Presence of lift yielded significant decrease in metabolic rate in knee-high boot compared to without lift. However, significant increase was observed in ankle-high boot with lift compared to without lift. Analysis of spatiotemporal parameters is ongoing to look for explanation for this result.

Conclusions: Use of RCWs increases metabolic rate. Increase in energy expenditure can be a factor leading to patient nonadherence with devices. Addition of contralateral lift decreased energy expenditure in the knee-high boot, likely improving user experience and thus improving adherence. Ongoing analyses are being conducted to explain paradoxical increase in energetic costs in ankle-high boot with lift compared to without contralateral lift. By improving user experience, we expect better adherence, thus maximizing healing potential of these devices.