The contribution of subacromial injection to the conservative treatment of impingement syndrome

Objectives: We evaluated the contribution of subacromial local anesthetic and corticosteroid injection to the conservative treatment of subacromial impingement syndrome. Methods: The study included 56 patients (39 women, 17 men; mean age 50 years; range 31 to 68 years) with subacromial impingement syndrome without any rotator cuff lesion. The patients were randomly allocated to injection and control groups equal in number. The former group received a single subacromial injection of 9 ml bupivacaine and 1 ml betamethasone at the beginning of the treatment. The same physical therapy and rehabilitation program was administered to both groups, consisting of 15 sessions (3 weeks). Evaluations were made before, and three and six weeks after treatment. Functional results were assessed using the Constant score, pain was assessed using a visual analog scale, and range of motion was measured with a goniometer. Results: Compared to pretreatment values, both groups exhibited significant improvements in pain score, Constant score, and range of motion measurements at three and six weeks (p<0.05). Pain score decreased by 37.7% in the injection group after 24 hours of injection. Pretreatment Constant scores which were 39.9 +/- 13.9 and 40.3 +/- 13.4 in the injection and control groups increased to 68.4 +/- 7.6 and 64.7 +/- 7.7 at six weeks, respectively. No significant differences were seen in pain scores between the two groups at three and six weeks (p>0.05). Patients receiving subacromial injection had significantly higher Constant scores at six weeks (p=0.044) and significantly greater external and internal rotation at three weeks (p=0.03). Range of motion measurements did not differ between the two groups at six weeks (p>0.05). Conclusion: Subacromial injection contributes to the success of the conservative treatment through decreasing pain and enabling more effective range of motion and strengthening exercises, both of which are associated with increased functional improvement.