Corticosteroid Dose and Efficacy in Shoulder Impingement Syndrome

To evaluate whether corticosteroid dose affects pain and functional outcomes in shoulder impingement syndrome (SIS) treated with subacromial injection. Systematic review and meta-analysis. Six databases (CINAHL, EMBASE, Ovid MEDLINE, Ovid HealthSTAR, PubMed, Web of Science) were searched from inception to July 2025. Outcomes were pooled using random-effects meta-analysis with meta-regression to assess association between dose and treatment effect. Twenty-three studies comprising 739 patients were included. Seven studies used triamcinolone-equivalent doses below 40 mg, while 16 used doses of 40 mg or more. The pooled improvement in pain was 3.00 points on the VAS (95% CI: 2.60-3.40). No significant association was found between corticosteroid dose and pain improvement ( =0.003, P =0.814), with pooled VAS improvements of 2.85 (95% CI: 2.50-3.20) and 3.06 (95% CI: 2.54-3.58) for the low and high dose groups, respectively. For functional outcomes, the overall pooled SMD was 1.876 (95% CI: 1.370-2.383), with no dose-response relationship ( =0.008, P =0.609). Subacromial corticosteroid injection produced clinically meaningful reductions in pain and improvement in function across the doses studied. These findings suggest a therapeutic ceiling effect, where lower doses may achieve comparable benefit; head-to-head trials are needed to confirm equivalence and establish optimal dosing guidelines.