Background Chronic ankle instability (CAI) patients have altered gait patterns characterised by increased ankle inversion motion prior to and following ground contact. Destabilisation devices may improve gait patterns in CAI patients by increasing peroneus longus muscle activity throughout the gait cycle.
Objective To determine whether incorporating destabilisation devices (device group) into a 4-week impairment-based rehabilitation program had beneficial effects on gait biomechanics and surface electromyography (sEMG) compared to impairment-based rehabilitation without destabilisation devices in CAI patients.
Design Single-blinded randomised controlled trial.
Patients Twenty-six CAI patients (age = 21.34 years; sex M = 7, F = 19; height = 168.96 cm, body mass = 70.73 kg) participated.
Interventions Patients completed baseline gait trials and were randomised into control or device groups. Both groups completed 4-weeks of rehabilitation with or without devices, then completed post intervention gait trials.
Main outcome measurements Ankle, knee, hip sagittal and frontal plane kinematics and kinetics and sEMG activity of the peroneus brevis, peroneus longus, anterior tibialis, and medial gastrocnemius were measured. Data was re-sampled to 100 frames, making each frame represent 1% of the gait cycle where 1% equals initial contact and 100% equals terminal swing. For each measure, group means and 90% confidence intervals (CI) were calculated across all 100 points of the gait cycle.
Results The device group increased dorsiflexion motion during mid-late stance (mean difference ± CI;% of cycle: 5.4 ± 2.4º; 45–64%) and had lower normalised sEMG amplitude for the peroneus longus during early stance (2.9 ± 1.4; 4–7%) and mid-swing (1.0 ± 0.5; 73–76%) after rehabilitation. The control group had less peroneus brevis sEMG activity during early stance (3.4 ± 1.3; 4–13%) after rehabilitation. There were no other differences following rehabilitation for either group or when the groups were combined.
Conclusion Incorporating destabilisation devices into a 4-week rehabilitation program are effective at increasing dorsiflexion motion during the stance phase of gait. However, impairment-based rehabilitation was not effective at altering frontal plane motion during gait.