Intra-articular Steroid Injection for Frozen Shoulder: A Systematic Review and Meta-analysis of Randomized Controlled Trials With Trial Sequential Analysis

Background: Intra-articular steroid injection is a common intervention for frozen shoulder (FS). Purpose: This review aimed to illustrate the effects of intra-articular steroid injection for FS. Study Design: Systematic review and meta-analysis. Methods: PubMed, Embase, and the Cochrane Library were searched for randomized controlled trials (RCTs) comparing intraarticular steroid injection with no injection or sham injections for FS. Visual analog scale (VAS) pain scores were the primary outcome measure. Secondary outcome measures included passive external rotation, abduction, flexion, internal rotation, and functional scores. Complication rates were the safety outcome measure. Comparisons were performed with mean differences (MDs) and 95% confidence intervals (95% CIs). Three time intervals were analyzed: 4 to 6 weeks, 12 to 16 weeks, and 24 to 26 weeks postintervention. Trial sequential analysis was used to verify the pooled results. Line charts were drawn to view the recovery trend in both the intervention and control groups. Results: Eight RCTs with 416 patients were included. Compared with controls, patients who received intra-articular steroid injection had significantly reduced VAS pain scores at 4 to 6 weeks (MD, 1.28 cm [95% CI, 0.75 to 1.82]), 12 to 16 weeks (MD, 1.00 cm [95% CI, 0.47 to 1.52]), and 24 to 26 weeks (MD, 0.65 cm [95% CI, 0.19 to 1.10]) postinjection. Trial sequential analysis confirmed the pooled results at 4 to 6 weeks and 12 to 16 weeks but not at 24 to 26 weeks. Patients who received intra-articular steroid injection had improved passive external rotation, abduction, and flexion and Shoulder Pain and Disability Index (SPADI) scores at all 3 time intervals, as well as improved American Shoulder and Elbow Surgeons (ASES) scores at 12 to 16 weeks (MD, 12.20 [95% CI, 2.55 to 21.85]). No difference was noticed in Constant scores (MD, 5.70 [95% CI, -0.59 to 11.99]) or internal rotation except at 12 to 16 weeks (MD, 0.81 degrees [95% CI, 0.18 degrees to 1.44 degrees]) and 24 to 26 weeks (MD, 3.88 degrees [95% CI, 0.51 degrees to 7.25 degrees]) between steroid injection and placebo. Complication rates were 1.78% for facial flushing, 0.71% for dizziness owing to vasovagal reactions during injection, 1.07% for chest or shoulder pain, and 0.36% for nausea. Line charts improved in both groups. Conclusion: Intra-articular steroid injection is effective and safe for FS and relieves pain, improves functional performance, and increases range of motion. The effects are significant at 4 to 6 and 12 to 16 weeks postintervention and may last as long as 24 to 26 weeks.