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

The Clinical Effectiveness of Pulsed Electromagnetic Field Therapy on the Management of Chronic Ankle Instability: A Double-Blinded Randomized Controlled Trial

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.

Study Overview

• Status: Completed
• Conditions: Chronic Ankle Instability
• Intervention / Treatment: Device: PEMF device, Quantum Tx, Singapore; Other: Standard rehabilitation and sham PEMF therapy for CAI

Detailed Description

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.

• Study Type: Interventional
• Enrollment (Actual): 62
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Hong Kong
  • Hong Kong
    • Hong Kong, Hong Kong, Hong Kong, New Territories
      • Prince of Wales Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 70 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

• 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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Active PEMF therapy for chronic ankle instability; Participants will be randomized into 1:1 allocation, blocked randomization with 20 participants in the PEMF group and 20 participants in the sham group. Each allocation will be assigned with a unique RFID (generated during block randomization by the PEMF supplier service) recognizable by the PEMF machine.	Device: PEMF device, Quantum Tx, Singapore; The options of the appliance will be adjusted to 1.5mT, 10Hz on the diseased leg for 10 minutes.
Sham Comparator: Sham PEMF therapy for chronic ankle instability; Control group will receive sham treatment on top of a standard rehabilitation (muscle strengthening and balance training).	Other: Standard rehabilitation and sham PEMF therapy for CAI; Balance training and muscle strengthening

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Centre of pressure during single leg stance for chronic ankle instability	Static balance will be conducted in double-leg and single leg stance with eyes opened and closed on the Tekscan pressure mat.	Baseline to 6 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Y balance test for chronic ankle instability	Dynamic balance	Baseline to 6 months
Dorsiflexion Range of motion for chronic ankle instability	The range of motion (ROM) will be measured by weight bearing lunge test (WBLT).	Baseline to 6 months
Foot muscle strength for chronic ankle instability population	Foot muscle strength will be carried out using a handheld dynamometer during ankle dorsiflexion, plantar flexion, inversion and eversion.	Baseline to 6 months
Ultrasound imaging for peroneal muscle in chronic ankle instability patients	The ultrasound imaging assessment of the peroneal muscle will be performed using Aixplorer (Supersonic Imagine, Aix-en-Provence, France).	Baseline to 6 months
Short Form 36 questionnaire (SF-36)	The 36 questions on the SF-36 are meant to reflect 8 domains of health, including physical functioning, physical role, pain, general health, vitality, social function, emotional role, and mental health. The categories of physical role and emotional role reflect performance at the activity and participation levels. To score the SF-36, scales are standardized with a scoring algorithm or by the SF-36v2 scoring software to obtain a score ranging from 0 to 100. Higher scores indicate better health status, and a mean score of 50 has been articulated as a normative value for all scales.	Baseline to 6 months
CAIT score	Cumberland Ankle Instability Tool (CAIT) score is a valid and reliable 9-item instrument used to identify self-perceived ankle instability. The instrument is scored on a 0 (worst) to 30 (best) scale, where a cut-off point of ≤ 24 denotes the presence of instability.	Baseline to 6 months
Lateral step-down test (LSDT)	LSDT is a clinical measurement that evaluates dynamic postural stability deficits and potential lower extremity injury. It measures the coordination of the lower limb joints, neuromuscular control, strength, pelvic stability, and range of motion.	Baseline to 6 months
The Manchester-Oxford Foot Questionnaire (MOxFQ)	It is validated 16-item, patient-reported outcome measure of foot and ankle pain and function	Baseline to 6 months
Numerical pain scale for chronic ankle instability	The numerical pain scale requires participants to rate their pain on a defined scale from 0-100. 0 refers to no pain while 100 refers to severe pain. Lower scores mean a better outcome.	Baseline to 6 months
Foot and ankle measure	Foot and Ankle Ability Measure (FAAM) will be used to assess the foot and ankle functional limitations among CAI individuals.	Baseline to 6 months
Dorsiflexion range of motion	Weight-bearing lung test (WBLT), based on the knee-to-wall principle, is a valid and reliable assessment that measures the dorsiflexion range of motion in CAI population.	Baseline to 6 months

Collaborators and Investigators

• Sponsor: Chinese University of Hong Kong

Publications and helpful links

General Publications

• Chia CSM, Fu SC, He X, Cheng YY, Franco-Obregon A, Hua Y, Yung PS, Ling SK. The clinical effects of pulsed electromagnetic field therapy for the management of chronic ankle instability: a study protocol for a double-blind randomized controlled trial. Trials. 2024 Dec 3;25(1):808. doi: 10.1186/s13063-024-08639-z.

Study record dates

Study Major Dates

• Study Start (Actual): January 2, 2023
• Primary Completion (Actual): January 31, 2025
• Study Completion (Actual): January 31, 2025

Study Registration Dates

• First Submitted: July 27, 2022
• First Submitted That Met QC Criteria: August 11, 2022
• First Posted (Actual): August 15, 2022

Study Record Updates

• Last Update Posted (Actual): March 25, 2026
• Last Update Submitted That Met QC Criteria: March 22, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Joint Diseases; Joint Instability; carboxyamido-triazole
• Other Study ID Numbers: 2022.263-T

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No