Can a simple steroid shot ease frozen shoulder pain?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. History of ≤9 months, clinically diagnosed with primary frozen shoulder (including frozen 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 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. 5. Exclusion of osteoarthritis, dislocation, and other shoulder abnormalities through X-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 in patients 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 shoulder injections. 5. Patients with contraindications to steroid therapy (e.g., poorly controlled blood sugar in diabetes). 6. Patients with frozen shoulder who have already undergone shoulder injections, manipulation under anesthesia, arthroscopic capsular release, or open surgery for capsular 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 contralateral shoulder. 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 or car accidents.