Flare Reaction Following Intra-articular Steroid Injection in Frozen Shoulder. A Retrospective Study

Objectives: The objectives of this study were to determine the incidence, severity, temporal profile, and management outcomes of flare reactions following ultrasound (US)-guided intra-articular steroid injection (IASI) for frozen shoulder. Methods: This retrospective study included adult patients undergoing US-guided glenohumeral joint IASI for frozen shoulder over 1 year. Flare reactions were assessed using the Numeric Rating Scale at 1-, 4-, and 24-h postinjection. Analgesic strategies were evaluated based on pain severity. Findings: Among 84 patients, flare reaction occurred in 19 (22.6%). Most reactions were mild (63.2%) and self-limiting. Moderate-to-severe reactions (36.8%) required pharmacological treatment. Early-onset severe pain responded rapidly to low-dose sublingual buprenorphine, with complete relief in most patients within 4 h, while late-onset moderate pain was effectively managed with oral diclofenac. No adverse effects were observed. Conclusion: Flare reaction after IASI for frozen shoulder is not uncommon and, in most cases, can be effectively managed with appropriate analgesic strategies. Sublingual buprenorphine for moderate-severe early-onset pain ensures effective symptom control without major side effects.