Combined Corticosteroid With Low Volume Compared to High Volume in Impingement Syndrome

Inclusion Criteria: 1. participants with clinically diagnosed the rotator cuff impingement 2. participants aged 20 years and older 3. at least 1 month's duration 4. pain of moderate to severe intensity, defined as a score of 5 or more points on a 10-cm visual analog scale (VAS) rated from 0 (no pain) to 10 (worst imaginable pain) Exclusion Criteria: 1. patients with adhesive capsulitis of the shoulder (normal radiograph of affected shoulder, and restriction of passive motion \>30° in ≥2 planes of movement) 2. previous trauma history at currently affected shoulder 3. previous corticosteroid injection history at the affected shoulder 4. abnormal calcification and/or primary osteoarthritis of the shoulder joint on plain radiographs 5. use of medication such as antiplatelet agent or anticoagulation.