Single-Site Corticosteroid Injection Is as Effective as Multisite Corticosteroid Injection in the Nonsurgical Treatment of Frozen Shoulder: A Systematic Review With Meta-Analysis of Randomized Controlled Trials

PURPOSE: To determine whether multisite corticosteroid injection is more effective than a single injection in the nonsurgical treatment of frozen shoulder (FS) via a meta-analysis of randomized controlled trials METHODS: We identified studies that evaluated the efficacy of multisite corticosteroid injections compared with single-site injection for FS. The Embase, PubMed, and Cochrane Library databases were systematically searched from inception to June 5, 2022. Methodologic quality and risk of bias were assessed using the Modified Coleman Methodology Score and the Cochrane Collaboration risk of bias tool, respectively. Visual analog scale scores, abduction, flexion, internal rotation, external rotation, American Shoulder and Elbow Surgeons Assessment Form scores, Constant–Murley Shoulder scores, and complications were extracted. The meta-analysis was conducted with random effects, and 4 time intervals were analyzed: 3 to 4 weeks, 6 to 8 weeks, 12 to 16 weeks, and 24 to 26 weeks RESULTS: The initial search identified 260 studies, and 5 randomized controlled trials that met the inclusion criteria were included. There were no significant differences in visual analog scale scores at 3 to 4 weeks, 6 to 8 weeks, 12 to 16 weeks, or 24 to 26 weeks. There were no significant differences in flexion or external rotation at 3 to 4 weeks, 6 to 8 weeks, 12 to 16 weeks, or 24 to 26 weeks. Multisite injection performed better in terms of abduction (mean difference –15.66 [–30.03, –1.28], P = .03) and American Shoulder and Elbow Surgeons Assessment Form score (mean difference –10.13 [–19.54, –0.72] P = .03) than single-site injection at 3 to 4 weeks. There were significant differences in internal rotation in favor of the multisite treatment at 3 to 4 weeks, 6 to 8 weeks, 12 to 16 weeks, and 24 to 26 weeks. In addition, there were no significant differences in complications. CONCLUSIONS: Single-site steroid injection is as effective as multisite corticosteroid injection for the nonoperative treatment of FS. LEVEL OF EVIDENCE: Level II, meta-analysis of Level I and II studies.