Combining Mechanical Support With Sensory Augmentation in Orthotic Devices for Postural Stability in Lateral Ankle Instability: A Randomised Controlled Trial.

Abstract

Background: Lateral ankle instability (LAI) frequently arises from deficits in sensorimotor function. Orthotic devices are regularly used to yield mechanical support, but the use of sensory-enriching modalities such as local vibration with these supports has not been explored.

Objective: This study was conducted to examine the effect of adding vibration to an orthotic device on postural stability in LAI.

Methods: In this parallel randomised controlled trial, 32 adults with LAI were entered into a trial group who received an ankle-foot orthotic device incorporating a vibratory strap or into a control group receiving the same orthosis without a vibration strap. Postural stability was evaluated with centre of pressure (COP) velocity on a force plate at four time points: baseline, immediately following intervention, 2-week follow-up, and 4-week follow-up. Finally, 29 participants completed the study protocol.

Results: There was a significant group × time interaction on COP anteroposterior velocity (F (3, 25) = 39.44, p < 0.001, η² = 0.82). The trial arm had a greater decrease in this outcome at 4-week follow-up compared with controls (MD = -0.90 mm/s, p < 0.001, d = -1.59). No differences were found for COP mediolateral velocity or COP resultant velocity, but there was a general trend of reduction in both groups.

Conclusion: The addition of sensory stimulation to orthotic devices significantly enhances anteroposterior postural stability in LAI subjects, suggesting a synergistic effect of mechanical support and sensory augmentation.