High-frequency Short-course Extracorporeal Shock Wave Therapy for Partial Rotator Cuff Tears: Study Protocol for a Multicenter, Randomized, Controlled Trial

This is a multicenter, randomized controlled clinical study exploring three different extracorporeal shock wave therapy (ESWT) regimens for patients with partial rotator cuff tears, a common cause of chronic shoulder pain and limited movement. Traditional ESWT uses a once-weekly treatment schedule over 7 weeks, which takes a long time and leads to low patient compliance. This study aims to test two new high-frequency, short-course ESWT protocols, compare their pain relief, shoulder function improvement, tendon healing effect, safety and treatment adherence with the conventional regimen, and finally establish a more efficient, patient-friendly standardized treatment plan for clinical use. A total of 300 eligible participants will be recruited from 10 top-tier hospitals across China and followed up for 12 months after treatment.

Inclusion Criteria: * Age 30-70 years, male or female * MRI- or high-resolution ultrasound-confirmed partial-thickness rotator cuff tear (predominantly supraspinatus) or small full-thickness tear without retraction or displacement * Shoulder pain duration ≥3 months with Visual Analog Scale (VAS) score ≥4 (0-10 scale) * Willing and able to provide written informed consent and comply with the study protocol Exclusion Criteria: * Large or massive full-thickness rotator cuff tear, tear with Grade II retraction or greater, or presence of a greater tuberosity bone cyst * Severe muscle fatty infiltration (Goutallier grade ≥3) on MRI * Uncontrolled diabetes mellitus (HbA1c \>7.5%), hypothyroidism, or heavy smoking (≥20 pack-years) * Received local injection therapy (e.g., corticosteroids, platelet-rich plasma) to the affected shoulder within 4 weeks prior to enrollment * Concurrent shoulder pathologies including glenohumeral osteoarthritis, adhesive capsulitis (frozen shoulder), or shoulder instability * Systemic diseases (e.g., rheumatoid arthritis), bleeding disorders, or coagulopathy * Pregnancy or lactation * Contraindications to ESWT (e.g., cardiac pacemaker, malignancy at treatment site) * Inability to complete treatment or follow-up schedule