Background Acute shoulder pain is a common rheumatologic symptom. Although there are multiple causes, it usually responds well to local steroid infiltration. Ultrasound (US), a simple non-invasive and accessible imaging modality is increasingly used to evaluate a wide spectrum of shoulder lesions in painful shoulder and has also been proposed to guide local steroid injection
Objectives To investigate the relation between pathological finding on ultrasound and the clinical response to steroid injection in terms of pain (i.e. assessed as rest pain and pain during daily activity) in patients with acute shoulder pain.
Methods 70 consecutive patients with acute shoulder pain were assessed clinically and by US. US findings were categorized, and an individual patient can have pathologies fulfilling >1 category. Patients were randomized to receive either a standard “blind” subacromial injection of 7mg of betamethasone or a US-guided injection directed toward the structure more susceptible to be the cause of pain. Follow-up evaluations were performed by an independent assessor who was not aware of the results of the initial US and clinical assessments. Initial US diagnoses were compared with respect to changes in the VAS pain score at 2, 6 and 12 weeks after the injection. We performed single and multiple regression analysis on each US diagnosis, in order to find one or more predictors of response.
Results The US findings and changes in night visual analogue scale (VAS) pain scores for each category are summarized in the following table.
At 2 and 6 weeks, all US diagnostic categories showed significantly reduced VAS pain scores compared to baseline. There was a clear trend toward reappearance of pain by 12 weeks in most categories.
Single and multiple regression analyses showed that the presence of calcification was the only significant predictor of a better response compared to other US diagnoses. This was valid only at 2 weeks post injection, for activity pain (p: 0.003) as well as rest pain (p: 0.05). The method of infiltration did not influence the results.
Conclusions Steroid injection significantly reduced pain in patients with acute shoulder pain whatever the initial US diagnosis. The presence of periarticular calcification is the only individual predictor of a better response, but only up to 2 weeks.
Disclosure of Interest None Declared