Comparison of Outcomes of Two Different Corticosteroid Injection Approaches for Primary Frozen Shoulder: A Randomized Controlled Study.

Objective: Corticosteroid injection is a common treatment for primary frozen shoulder, but controversy remains regarding whether different injection approaches to the glenohumeral joint have similar clinical benefits.

Design: Randomized controlled clinical trial.

Patients: A total of 60 patients with primary frozen shoulder were divided randomly into either anterior or posterior approach groups.

Methods: Both groups received a 5-mL drug injection, including 1 mL 40 mg/mL triamcinolone acetonide and 4 mL 2% lidocaine. Follow-up time-points were 4, 8 and 12 weeks post-injection. Outcome measures included visual analogue scale score, Constant-Murley score, and passive range of motion of the shoulder joint.

Results: All outcome measures improved over the follow-up period compared with those of previous follow-up time-points within the groups. The primary finding was that the visual analogue scale score in the anterior group was better than that in the posterior group at each follow-up time-point (all p < 0.05). In addition, improvement in function score and external rotation was faster and significant in the anterior group in the early stages (p = 0.02).

Conclusion: The anterior approach achieves more satisfactory results in pain control and offers better recovery of functional activity than posterior approach in the early period for primary frozen shoulder.