The Clinical Effectiveness of Pulsed Electromagnetic Field Therapy on the Management of Chronic Ankle Instability

This study aims to investigate the clinical effectiveness of PEMF as an adjunct to a program of standard rehabilitation for the treatment of chronic ankle instability. The study objective is to establish whether PEMF plus standard rehabilitation in people with chronic ankle instability compared to standard rehabilitation. This study also investigates the effects of PEMF on pain, functional outcomes, and mechanical and morphological properties of peroneal muscles in chronic ankle instability. Investigators hypothesize that pulsed electromagnetic field therapy is effective in reducing pain, improving functional outcomes, and restoring mechanical and morphological properties.

This study is a double-blinded, randomized controlled trial to investigate the clinical effects of pulsed electromagnetic field therapy (PEMF) for chronic ankle instability. Participants will be recruited from the outpatient clinic of the orthopedic and traumatology department at Prince of Wales Hospital.

40 patients aged between 18 to 60 years old with CAI will be invited to join this trial after informed consent. Participants will be randomized to any of the 2 groups: the intervention group (n=20; PEMF (Quantum Tx) treatment), and the control group (n=20; sham treatment with dummy exposure to PEMF).

For Chronic Ankle Instability patients: baseline measurements of all self-reported outcomes, functional outcomes, and ultrasound imaging assessments, such as dynamic balance, static balance, single leg hop test, gait evaluation, dorsiflexion range of motion, and eversion muscle strength.

The primary objective is to investigate the effectiveness of PEMF therapy on the clinical and functional outcomes in the CAI population. We hypothesize that PEMF therapy will effectively improve the clinical and functional outcomes of patients with CAI.

Methods: This is a prospective, randomized, double-blinded, placebo-controlled trial with blinded assessors. A total of 40 adults with CAI will be recruited and randomly allocated into either the intervention or control group. In the intervention group, the participants (n=20) will receive active PEMF therapy and standard exercise training, while the control group (n=20) will receive sham-PEMF therapy and standard exercise training. The PEMF intervention will last for 8 weeks. The primary and secondary outcomes will be evaluated at baseline, week 4, week 8, 3rd month, 6th month after the PEMF therapy.

Rationale: Pulse electromagnetic field therapy (PEMF) as an adjunct biophysical therapy can improve stability by mitigating peroneal muscle weakness and activating peroneal muscle. Therefore, we postulate the combination of standard care (muscle strengthening, balance training, and range of motion exercise) augmented with pulse electromagnetic field therapy elicits a significant improvement in postural control stability and peroneal muscle weakness.

Eligibility Criteria:
* Inclusion in the CAI stratum:
* Requires a history of at least one significant sprain \> 12 months prior to consent
* Continued perceived or episodic "giving way" of the ankle
* Reported Cumberland Ankle Instability Tool (CAIT score \< 24)

Exclusion Criteria for CAI:

* A history of surgeries or fractures of either lower extremity limbs
* Concomitant lower extremity pathology, e.g. vascular disease and osteoarthritis
* Inadequate muscle strength in lower limb which require ambulation support (e.g., crutches) or any vestibular or balance disorders
* Pregnancy
* Cognitive impairment/Neurological conditions, and neurological disorders (e.g. dementia) -Concussion within the last 6 months
* Bilateral instability condition
* Regular use of medicine or antibiotics
* Metal implantation in their body
* Unable to walk at enrolment
* Non-removable cast