13 Using a new classification system of posttraumatic ankle instability to quantify levels of neuromuscular and perceived function

Abstract

Background Separating chronic ankle instability (CAI) into subgroups based on the major clinical symptoms of CAI, including perceived ankle instability (PI), repeated episodes of “giving-way”, and recurrent ankle sprains (RAS), may create more homogenous subgroups of participants with CAI and could help to identify mechanical, neuromuscular, and psychological characteristics in individuals with CAI. Objective To determine if selected sensorimotor, mechanical, and self-reported measures are different among PAI subgroups healthy control participants, and PAI-copers. Design Single-blinded, case-control. Setting Research laboratory. Participants Ninety-three participants (40M, 53F; age = 21.81 ± 3.63 years; BMI = 24.94 ± 4.26 kg/m 2 ) volunteered and were categorised into PI in combination with RAS (PI-RAS; n = 25), PI alone (n = 13), RAS alone (n = 12), PAI-copers (n = 18), and controls (n = 25). Interventions Participants completed self-assessed global, regional, and psychological health-related questionnaires and assessments of neuromuscular and mechanical joint stability. Main outcome measurements Neuromuscular outcomes included spinal reflex excitability of the soleus muscle (H max :M max ratio) and static postural control assessed with the mean of time-to-boundary minima in the anterior-posterior (TTB-AP) and medial-lateral directions (TTB-ML). For mechanical outcome measures, ankle joint laxity was measured using an ankle arthrometer. Self-reported outcomes included the Foot and Ankle Ability Measure Activities of Daily Living (FAAM-ADL), the FAAM-Sports, the Tampa Scale of Kinesiophobia-17, and Physical and Mental Summary Components of the Short-Form 36. A backward, stepwise, multinomial logistic regression was used to determine the most influential factors to classify group membership. Cohen’s d effect sizes were calculated to determine the magnitude of difference in the most influential factors between groups. Results Five outcome measures (H max :M max ratio, TTB-AP, TTB-ML, FAAM-ADL, FAAM-Sports) were the best set of indicators of group membership (χ 2 (20) = 128.67, p Conclusions The combination of PI and RAS appears to lead to greater degree of neuromuscular and perceived dysfunction compared to CAI-copers and healthy controls.