Effect of Leg Length–Evening Device on Perceived Balance in Patients Wearing a Controlled Ankle Motion Boot

Abstract

Background: Patients are often made weightbearing as tolerated (WBAT) in a controlled ankle motion (CAM) boot for the management of various foot and ankle conditions. The CAM boot causes a leg length discrepancy (LLD) between the booted (longer) and contralateral (shorter) lower extremities. This discrepancy can potentially cause balance problems, undue strain on joints, and discomfort in patients. We hypothesized that a leg length–evening orthotic placed on the plantar aspect of the contralateral shoe improves balance among patients who are WBAT in a CAM boot. Methods: Patients made WBAT in a CAM boot were randomized to either the leg length–evening orthotic intervention group or to a control group in which patients wore a normal shoe of their choice. Patients were followed for 2 weeks and asked a series of questions pertaining to balance and pain experienced at their knees, hips, and back. Balance was the primary outcome and was scored from 0 (no difficulty with balance) to 10 (great difficulty with balance). Of 107 subjects enrolled and randomized, 95 (88.8%) completed the study, satisfying the a priori sample size requirement of 94 patients. There were no differences in baseline characteristics between groups ( P > .05 for each). Results: Intervention patients reported less difficulty with balance than control patients (intention-to-treat analysis: 2.0±1.5 vs 3.2±1.8, P = .001; as-treated analysis: 2.1±1.7 vs 3.0±1.7, P = .009). Intervention and control patients did not differ with respect to pain experienced at their knees, hips, or back, or in a composite total pain score ( P > .05 for each). Conclusion: This multicenter randomized controlled trial found that adding a limb length–evening orthotic to the plantar aspect of the contralateral shoe in a patient that is WBAT in a CAM boot improved patient-reported self-assessment of balance. The trial was powered to identify a difference in the primary outcome measure of balance and may have been insufficiently powered to identify differences in knee, hip, back, or total pain. Level of Evidence: Level II, prospective comparative study.