Ultrasound-Guided Versus Blind Subacromial Corticosteroid Injections for Subacromial Impingement Syndrome: A Randomized, Double-Blind Clinical Trial

Background: Subacromial corticosteroid injections are frequently performed for impingement syndrome of the shoulder. To improve the accuracy of injections, ultrasound can be used. Purpose: To assess the clinical outcome of ultrasound-guided subacromial injections compared with blind subacromial injections for subacromial impingement syndrome. Study Design: Randomized controlled clinical trial; Level of evidence, 1. Methods: A total of 56 shoulders with subacromial impingement syndrome were randomized into 2 groups: 28 shoulders received a subacromial corticosteroid injection with ultrasound guidance (ultrasound group), and 28 shoulders received a subacromial corticosteroid injection without ultrasound guidance (blind group). The visual analog scale (VAS) for pain with overhead activities and the American Shoulder and Elbow Surgeons (ASES) score were obtained before the injection and at 6 weeks after the injection. Results: The VAS score for pain with overhead activities decreased from 59 5 mm (mean SEM) before the injection to 33 +/- 6 mm at 6 weeks after the injection in the ultrasound group (P < .001) and from 63 +/- 4 mm to 39 +/- 6 mm, respectively, in the blind group (P < .001). The decrease in the VAS score was not significantly different between the groups (P > .999). The ASES score increased from 57 +/- 2 before the injection to 68 +/- 3 at 6 weeks after the injection in the ultrasound group (P < .01) and from 54 +/- 3 before the injection to 65 +/- 4 after the injection in the blind group (P < .01), with no significant difference between the groups (P = .7). Four shoulders (14%) in the ultrasound group and 6 shoulders (21%) in the blind group eventually needed surgery (P = .7). Conclusion: No significant differences were found in the clinical outcome when comparing ultrasound-guided subacromial injections to blind subacromial injections for subacromial impingement syndrome.