Comparison of Ultrasound-Guided Subacromial vs. Systemic Steroid Injections for Frozen Shoulder: a Multicenter Pilot Study

Inclusion Criteria:

1. History of ≤9 months, clinically diagnosed with primary frozen shoulder (includingfrozen shoulder associated with diabetes).

2. Aged between 18 and 75 years old

3. Pain NRS score ≥4

4. Measured passive range of motion of the affected shoulder in at least two of thethree directions (forward flexion, external rotation with arm at the side, andinternal rotation with arm at the side) is reduced by 25% or more compared to thecontralateral normal shoulder.

5. Exclusion of osteoarthritis, dislocation, and other shoulder abnormalities throughX-ray and MRI of the affected shoulder.

Exclusion Criteria:

1. Secondary frozen shoulder caused by thyroid disease, cardiovascular disease, cancer,stroke, radiotherapy, neurosurgery, or breast surgery (excluding diabetes);secondary frozen shoulder caused by major shoulder trauma requiring medical care (e.g., fractures, dislocations, rotator cuff tears).

2. Full-thickness rotator cuff tear in the affected shoulder confirmed by MRI (excluding rotator cuff tendinopathy and partial-thickness rotator cuff tear inpatients with frozen shoulder without a history of major shoulder trauma).

3. Patients unable to undergo MRI due to financial reasons, claustrophobia, pacemaker,or other metallic implants in the body.

4. Local infection in the affected shoulder or other contraindications to shoulderinjections.

5. Patients with contraindications to steroid therapy (e.g., poorly controlled bloodsugar in diabetes).

6. Patients with frozen shoulder who have already undergone shoulder injections,manipulation under anesthesia, arthroscopic capsular release, or open surgery forcapsular release.

7. Received any form of steroid treatment within the past 3 months.

8. History of glucocorticoid use for more than 3 months.

9. Bilateral frozen shoulder or a history of frozen shoulder in the contralateralshoulder.

10. Pregnant or breastfeeding women.

11. Patients lacking the cognitive ability to comply with the study protocol.

12. Patients not residing in the area where the study is being conducted.

13. Patients with compensation claims or legal disputes related to workplace injury orcar accidents.