The incidence of flare reaction and short-term outcome following steroid injection in the shoulder

BACKGROUND: To determine the short-term effects following corticosteroid injection into the shoulder. METHODS: Type-specific shoulder injection was administered, followed by physiotherapy 7 days to 10 days later. One hundred and sixteen adult patients were prospectively followed-up. The primary outcome was a visual analogue score (VAS) for pain. Scores were recorded immediately before injection, 30 minutes after, daily until day 7 and then at 6 weeks. Post injection pain was defined as an increase of 2 or more points in the VAS score after the injection. The secondary outcome was determined at 6 months as successful discharge or progression onto surgery. RESULTS: The VAS showed a significant reduction from the pre-injection score for all patients at day 1 and was maintained until week 6. Forty-one (35.3%) patients experienced post-injection pain. The mean duration of symptoms was 3.9 days. At 6 months, 81 (69.8%) patients were discharged successfully and, at a mean of 23.2 months, did not require re-referral; 29 (25%) had surgery; and six (5.2%) were referred for a spinal opinion. CONCLUSIONS: One in three patients developed delayed post-injection pain. Flare phenomenon had no determinate effect on outcome. Patients' pain response by 6 weeks is predictive of final outcome at 6 months and may help clinicians plan further treatment without delay.