Does using ultrasonography to guide steroid injections into the shoulder region improve pain or function compared with using anatomic landmarks alone?
Ultrasound-guided glucocorticoid injection for shoulder pain provides no advantage over landmark-guided or intramuscular injection in terms of pain, function, range of motion, or safety when measured within a six-week follow-up period. However, the small sample size of this review means that a clinically significant benefit cannot be ruled out. (Strength of Recommendation: B, based on inconsistent or limited-quality patient-oriented evidence.)
Traditional shoulder injections are performed using anatomic landmarks alone (i.e., blind). A 2003 Cochrane review showed modest benefits from steroid injection for rotator cuff disease and adhesive capsulitis, and effects were short-lived.1 However, other studies have shown that the accuracy of needle placement into the subacromial bursa or glenohumeral joint is highly variable. Ultrasound-guided injections appear to increase accuracy, but there is conflicting evidence as to whether they provide any advantage over blind injections in terms of patient-oriented outcomes.
The authors of this Cochrane review analyzed five studies with 290 participants (randomized and quasirandomized controlled trials) to compare ultrasound-guided steroid injection with blind or gluteal steroid injection. Of the four trials that included participants with rotator cuff disease, subacromial bursitis, or both, three compared ultrasound-guided injection with blind injection into the subacromial bursa, and one compared ultrasound-guided subacromial injection with gluteal injection. The fifth trial included participants with adhesive capsulitis, and the injection (either blind or ultrasound-guided) was directed into the glenohumeral joint. No trial had more than six weeks of follow-up. Primary outcomes included pain and function.
The authors found no significant differences between groups in pain reduction at any of the end points. In data pooled from three studies, range of abduction improved by about 20 degrees at two weeks with ultrasound-guided injection. However, statistical heterogeneity was considerable, and benefits were not seen at other time points. Minor adverse events such as transient postinjection pain and facial redness were rare and occurred equally in the control and ultrasound-guided treatment groups.
Only one study was assessed to have a low risk of bias; it compared ultrasound-guided subacromial injection with systemic gluteal injection.2 No differences in pain or function were noted between groups during a six-week follow-up, suggesting that any benefit of the injection was likely from its systemic effects and not dependent on injection location.
Four of the studies did not specify or account for oral analgesic use, which could have affected the clinical end point. In three studies, 20 mg of triamcinolone was used as the injectate, which some may consider a low dose. In a letter to the editor following the gluteal injection controlled study, a critic questioned the validity of rotator cuff disease as a specific disease entity and asked how a subacromial injection could possibly reach all affected tendons and problem areas.3 A recent review discusses the most useful techniques for accurately diagnosing rotator cuff disease.4
Future studies should address glenohumeral arthritis (such cases were largely excluded from this meta-analysis). Confirmatory studies also should be performed to compare local injection with systemic intramuscular injection or oral glucocorticoid use.
Although evidence of increased effectiveness is lacking, attempting to accurately administer steroid injections to their target location is still considered standard of care. Point-of-care ultrasonography can be helpful when training health care professionals to see and feel where the injection is going. Various pathologies also can be visualized with ultrasonography. A four-minute video of a clinician performing ultrasonography of shoulder structures and administering a subacromial injection is available at http://www.youtube.com/watch?v=Z161HyusPhg&feature=related. More short videos of ultrasonographic techniques for specific tendons and structures can be accessed at http://radiographics.rsna.org/content/suppl/2005/12/05/e23.DC1. Pictorial essays of shoulder ultrasonography are available online at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3424700 and http://radiographics.rsna.org/content/26/1/e23.long.