Neuromechanical Strategies Adopted by Chronic Ankle Instability Patients: Perspectives on Re-injury
Symposium Chair: Ty Hopkins
Background & Relevance: Chronic ankle instability (CAI) has been characterized by various signs and symptoms, including “giving way” episodes and re-injury. Several instruments have been used to identify patients who suffer from CAI. These self-report instruments allow a relatively clean subject population from which sensorimotor deficits may be identified. The goal of these data is to identify deficits or alterations that may perpetuate the chronic nature of instability and the consequences that may stem from them. This is ultimately done in an effort to design interventions specific to the deficits. Our data describe potential neuromechanical deficits from 6 distinct movement patterns identified from 200 patients with CAI. We will review kinematic and kinetic differences from the various movement patterns relative to healthy subjects and highlight alterations that may be problematic to CAI patients. We will also review descriptive data and clinical test data, and their ability to predict specific movement patterns within the CAI sample.
In addition to describing the neuromechanics of an existing CAI population, evaluation of re-injury within this population may provide keys as to specific movement mechanics that increase the susceptibility within the population. Our sample of CAI patients was followed over 12 months to identify those who were re-injured. Relative to activity level and exposure, we will review the unique movement characteristics of those who were re-injured, which may provide clues as to what specific mechanics may be key to re-injury. In summary, relative to the non-reinjury group, the re-injury group demonstrated greater plantarflexion, knee extension, hip flexion, inversion, knee abduction, and hip abduction internal joint moment during the initial landing phase of a demanding jump/cut task. The reinjury group also demonstrated greater eccentric ankle, knee and hip joint power during the landing phase. Finally, the re-injury group revealed greater medial, posterior and vertical ground reaction force during initial landing phase. During the final portion of our presentation, we will discuss the predictability of the re-injured CAI patients from descriptive and clinical test data. Five descriptive or clinical test scores may predict the risk of ankle re-injury in patients with CAI: (1) Greater number of giving way episodes (Odds Ratio (OR): 5.19), (2) Higher arch height index; supinated foot (OR: 2.96), (3) Poor static Biodex balance stability (OR: 1.31), (4) Slower figure of 8 hop test (OR: 1.32), and (5) Lower passive dorsiflexion ROM (OR: 1.11).
Speaker 1: Ty Hopkins
Presentation title: Characterization and Prediction of Specific Movement Patterns Associated with Chronic Ankle Instability
Speaker 2: Hyunsoo Kim
Presentation title: Biomechanical Risk Factors for Recurrent Ankle Sprains During Landing and Cutting
Speaker 3: S. Jun Son
Presentation title: Prediction of Recurrent Ankle Sprains Based on Descriptive and Clinical Test Data