Clinical Study of Wearable Low-Intensity Pulsed Ultrasound for Improving Motor Function in Patients with Chronic Ankle Instability

INTERVENTION: True stimulation group:True stimulation group received low‐intensity pulsed ultrasound therapy with intensity of 0.5 W/cm^2;Sham stimulation group:Sham stimulation group received sham stimulation treatment with identical appearance, procedure, and duration as true stimulation, but without outputting effective ultrasound energy; CONDITION: This study focuses on the central neuromodulatory mechanisms underlying chronic ankle instability (CAI). Based on the theoretical framework of “peripheral injury–central reorganization–motor dysfunction,” it aims to investigate the clinical value of wearable low‐intensity pulsed ultrasound (LIPUS) targeting the supplementary motor area (SMA) for promoting motor function recovery in patients with C PRIMARY OUTCOME: Changes in CAIT Scores; SECONDARY OUTCOME: Zung Self‐Rating Depression Scale (SDS);Joint Position Reproduction Test (JPR Test);Y‐balance;Zung Self‐Rating Anxiety Scale (SAS);Tampa Scale for Kinesiophobia (TSK);Anterior Drawer Test (ADT);Functional Magnetic Resonance Imaging (fMRI); INCLUSION CRITERIA: 1. Unified inclusion criteria (1) Age >18 years (2) Conscious and able to complete the prescribed measurement tasks (3) Voluntarily participate in the study, sign the informed consent form, and comply with study requirements 2. Inclusion criteria for patients with chronic functional lateral ankle instability (1) History of unilateral ankle sprain for more than 6 months, confirmed by two experienced foot and ankle specialists, with negative anterior drawer and/or inversion stress tests on the affected ankle, and the contralateral ankle is healthy or has no history of sprain (2) No accompanying fractures, distal tibiofibular syndesmosis separation, or other severe ankle injuries or disorders of other lower extremity sites (3) The first injury occurred more than 6 months ago, and in the past 6 months, there has been a history of "giving way" or frequent sensation of foot or ankle instability (4) Foot and Ankle Ability Measure (FAAM) s