Unable to find participants willing to join the trial.

The aim of our study is to investigate the efficacy of high energy density pulse electromagnetic field for patients with frozen shoulder

Frozen shoulder causes shoulder pain and limited range of motion(ROM). It is thought to afflict between 2 and 5% of the general population. Individuals of middle age are most often affected, typically during the 5th to 7th decades of life. Typical symptoms include gradual onset of shoulder pain, limited shoulder ROM at least in two or more directions (especially in external rotation). In the case of primary adhesive capsulitis, the disease is usually self-limiting, and typically lasts 18-24 months. However, persistent symptoms and movement restriction beyond 3 years have been reported in up to 40% of patients, with up to 15% of patients suffering permanent disability. Therefore, an effective treatment is necessary to treat the shoulder pain and disability caused by frozen shoulder. High energy density pulse electromagnetic field (High-PEMF), different from traditional PEMF, includes characteristics as following:

1. The short pulse duration (50μs) with a damped oscillation
2. The broad bandwidth(200kHz~300MHz) with a basic frequency 240kHz
3. High voltages (up to 40 kV) and peak currents (up to 10 kA) arise in the applicator spool
4. Delivery of energy per pulse of about 96Ws (Joule) with a magnetic flux density of 50~100mT
5. Depth penetration for tissue and organ up to 20 cm

It has been applied in chronic tendinopathy with positive outcomes. However, few studies support its application in the setting of frozen shoulder. Hence, the aim of our study is to investigate the efficacy and the underlying possible mechanism of High-PEMF for patients with frozen shoulder.

Inclusion Criteria:

1. Frozen shoulder is diagnosed by physicians based on the patient's medical history, physical examination, X-ray, and ultrasound reports.
2. The symptoms persist for more than 3 months.
3. There is a reduction of at least 30 degrees in at least two of the affected shoulder joint angles compared to the angles of the healthy side: shoulder flexion, abduction, and external rotation.

Exclusion Criteria:

1. Shoulder musculoskeletal ultrasound reveals a full-thickness tear or massive tear of the shoulder rotator cuff tendons or calcific tendinitis.
2. Systemic rheumatic disease.
3. History of shoulder fracture or previous surgical treatment of the shoulder joint.
4. Acute cervical nerve root compression.
5. Patients with instability (e.g., those with symptoms of internal bleeding) or cancer patients.
6. Received shoulder injections for treatment within the past 3 months.
7. Impaired cognitive function that prevents the patient from providing informed consent or participating in rehabilitation therapy.
8. Pregnant or breastfeeding women.
9. Meets any of the contraindications for high-energy electromagnetic pulse therapy: organ transplant recipients; individuals with implanted cardiac pacemakers, defibrillators, metal implants (such as stents), cochlear implants, and insulin supplementation.