Optimizing Retention on Duty in Patients with Chronic Ankle Instability using Auditory Biofeedback Gait Training: A Multi-Site Randomized Controlled Trial

TECHNICAL ABSTRACT Background: Ankle injuries account for the highest musculoskeletal injuries among conventional and special warfare combatants. In the civilian population, 40% of lateral ankle sprain patients will develop chronic ankle instability (CAI). If the same frequency is true in military settings, then up to 36,800 service members develop CAI annually. CAI contributes to the total number of medically non-available service members, creates a substantial economic burden, impacts the quality of duty-relevant task performance, and generates a large population of service members who require long-term care after retirement. There are no evidence-based gait training interventions for patients with CAI despite abnormal biomechanical patterns leading to recurring injuries linked to ankle osteoarthritis (OA) development. Overall, the current rehabilitation strategies are insufficient for preventing complications following an ankle sprain. Hypothesis/Objectives: The overall objective of this study is to examine the effects of gait training with auditory feedback (AudFB) on gait biomechanics, ankle joint health, and patient-centered outcomes. Our central hypothesis is that a 6-week (12 sessions) gait training with AudFB will lead to short and long-term improvements in walking, rucking, and running biomechanics, talar cartilage deformation patterns, and re-injury rates and severity of symptoms. Specific Aims: Aim 1: Determine if a 6-week gait training with AudFB improves lower extremity biomechanics compared to a Control condition in participants with CAI. Aim 2: Determine if a 6-week gait training with AudFB reduces talar cartilage deformation compared to a Control condition in participants with CAI. Aim 3: Determine if a 6-week gait training with AudFB reduces ankle giving-way episodes and severity of CAI symptoms relative to a Control condition in participants with CAI. Study Design: We will utilize a multi-site, single-blinded, randomized controlled trial study design to address the specific aims. All participants will complete a baseline testing session, 12 intervention sessions, a post- intervention testing session, and a 6- and 12-month post-intervention testing session. We will test our hypothesis by comparing outcomes at post-intervention, 6- and 12-month post-intervention to baseline. Impact and Military Benefit: We expect patients with CAI will exhibit improvements in patient-centered outcomes and subsequent clinician-centered outcomes regarding biomechanics, ankle joint health, and neural plasticity. These findings will signal that our novel AudFB gait training protocol is critical to short- and long- term quality of life in patients with CAI. This study will provide a short-term impact by providing clinicians with an easily accessible and feasible tool to implement gait training to optimize return to duty in service members with CAI history. The long-term impact of this study will be related to the expansion of the rehabilitation paradigm by providing an evidence-based gait training protocol that has the potential to mitigate the early onset of ankle OA.