Comparison Between Ultrasound Guided Subacromial and Systemic Injection of Steroid for Frozen Shoulder: a Double Blind Multicenter Pilot Study for Randomized Control Trial
The goal of this multicenter pilot study is to validate the effectiveness of extending the injection interval between betamethasone doses from one to two weeks for treating frozen shoulder (adhesive capsulitis) in adults aged 18 to 75. This study also aims to screen potential study centers and gather data to refine the sample size calculation for a larger, future trial. The main questions it aims to answer are: * Does extending the interval between injections maintain effectiveness in improving shoulder function and reducing pain for frozen shoulder? * Which centers in this pilot study are qualified for a larger, future trial? * What is the appropriate sample size for conducting a multicenter RCT study with the same research design at the selected centers? Participants will: * Receive 3 injections over 4 weeks and will be followed up for another 8 weeks * Complete shoulder function assessments * Perform home rehabilitation exercises
• History of ≤9 months, clinically diagnosed with primary frozen shoulder (including frozen shoulder associated with diabetes).
• Aged between 18 and 75 years old
• Pain NRS score ≥4
• Measured passive range of motion of the affected shoulder in at least two of the three directions (forward flexion, external rotation with arm at the side, and internal rotation with arm at the side) is reduced by 25% or more compared to the contralateral normal shoulder.
• Exclusion of osteoarthritis, dislocation, and other shoulder abnormalities through X-ray and MRI of the affected shoulder.