Rotator Interval vs Posterior Approach Ultrasound-guided Corticosteroid Injections in Primary Frozen Shoulder: A Meta-analysis of Randomized Controlled Trials

Abstract

Objective: To compare the efficacy of rotator interval (RI) vs posterior approach (PA) ultrasound (US) guided corticosteroid injections into the glenohumeral (GH) joint in primary frozen shoulder (PFS).

Data sources: A systematic literature search for all relevant studies on Medline, Scopus, Embase, Web of Science, and Cochrane Central, up to January 2023 was conducted.

Study selection: Randomized controlled trials that directly compared the US-guided corticosteroid injection into the RI and GH joint using PA in patients clinically and radiographically diagnosed with PFS.

Data extraction: The primary outcome was pain, and the secondary outcomes were function, and range of motion (ROM). Two authors independently assessed the risk of bias using the Cochrane risk-of-bias tool version 2. A random-effects model and generic inverse variance method were performed. Effect sizes were estimated using mean difference (MD) and standardized mean difference (SMD).

Data synthesis: A total of 5 clinical trials involving 323 subjects were included for the meta-analysis. US-guided corticosteroid injections into the RI revealed significant pain relief (MD 1.33 [95% confidence interval (CI) 0.20 to 2.46]; P=.02) and significant functional improvement (SMD 1.31 [95% CI 0.11 to 2.51]; P=.03) compared with the PA after 12 weeks.

Conclusion: The results suggest the injection of corticosteroid into RI space is more effective than PA after 12 weeks in improving both pain and functional scores in patients with PFS.

Keywords: Adhesive capsulitis; Corticosteroid injection; Frozen shoulder; Intra-articular; Meta-analysis; Randomized controlled trial; Rehabilitation; Rotator interval; Ultrasound.