39 Predicting the initial response to joint mobilisation in individuals with chronic ankle instability: a pilot study

Abstract

Background Joint mobilisation (JM) has demonstrated the ability to improve mechanical, neurophysiological, and self-reported function in people with chronic ankle instability (CAI). Objective To identify the predictors of an initial positive response to JM in individuals with CAI. Design Case series. Setting Laboratory. Participants Twelve adults (6 females; age = 27.4 ± 4.3 years; height = 175.4 ± 9.7 cm; body mass = 78.4 ± 11.0 kg) with self-reported CAI participated. Subjects reported ≥1 ankle sprain, ≥2 episodes of ankle “giving way” in the past three months, and Foot and Ankle Ability Measure-Sport (FAAM-Sport) scores ≤80%. Interventions The JM intervention entailed 6 treatments over 2 weeks consisting of 2, 2-minute sets of Maitland grade-II talocrural traction and 4, 2-minute sets of Maitland grade-III anterior-to-posterior talocrural JM. Main outcome measurements Subjects were grouped as responders or non-responders based on changes in perceived overall function (normal, nearly normal, abnormal, severely abnormal) one week following the intervention. Data collected prior to the intervention (FAAM-ADL, FAAM-Sport, previous sprains, episodes of instability, activity level, dorsiflexion, anterior/posterior talar glide, dynamic balance, failed balance trials) were compared between groups using independent t-tests. Variables with a p-value ≤ 0.20 were entered into stepwise logistic regression. Individual variables retained in the regression model were examined for discriminative capabilities and cut-off scores using receiver operating characteristic curves. Results Six subjects were deemed responders and demonstrated lower pre-intervention FAAM-ADL scores and greater normalised anterior reach on the Star Excursion Balance Test (anterior-SEBT) compared to non-responders (p ≤ 0.14). Logistic regression determined the combination of FAAM-ADL and anterior-SEBT scores correctly classified 75% of cases. A Hosmer-Lemeshow test indicated the model fit the data (p = 0.35). Cut-off scores for the FAAM-ADL and anterior-SEBT were 77.4% (sensitivity = 0.83, specificity = 0.83) and 73.5% (sensitivity = 0.83, specificity = 0.83), respectively. Conclusions Responders exhibited lower FAAM-ADL and greater anterior-SEBT scores compared to non-responders. Dorsiflexion range of motion and talar glide were not predictive of overall JM treatment outcomes despite being common impairments for prescribing this intervention.