Background: Immobilization after closed reduction has long been the standard treatment for primary anterior dislocation of the shoulder. To determine the optimum duration and position of immobilization to prevent recurrent dislocation, a systematic review of the relevant literature was conducted.

Methods: Of 2083 published studies that were identified by means of a literature review, nine Level-I and Level-II studies were systematically reviewed. The outcome of interest was recurrent dislocation. Additional calculations were performed by pooling data to identify the ideal length and position (external or internal rotation) of immobilization.

Results: Six studies (including five Level-I studies and one Level-II study) evaluated the use of immobilization in internal rotation for varying lengths of time. Pooled data analysis of patients younger than thirty years old demonstrated that the rate of recurrent instability was 41% (forty of ninety-seven) in patients who had been immobilized for one week or less and 37% (thirty-four of ninety-three) in patients who had been immobilized for three weeks or longer (p = 0.52). An age of less than thirty years at the time of the index dislocation was significantly predictive of recurrence in most studies. Three studies (including one Level-I and two Level-II studies) compared recurrence rates with immobilization in external and internal rotation. Analysis of the pooled data demonstrated that the rate of recurrence was 40% (twenty-five of sixty-three) for patients managed with conventional sling immobilization in internal rotation and 25% (twenty-two of eighty-eight) for those managed with bracing in external rotation (p = 0.07).

Conclusions: Analysis of the best available evidence indicates there is no benefit of conventional sling immobilization for longer than one week for the treatment of primary anterior shoulder dislocation in younger patients. An age of less than thirty years at the time of injury is significantly predictive of recurrence. Bracing in external rotation may provide a clinically important benefit over traditional sling immobilization, but the difference in recurrence rates did not achieve significance with the numbers available.

Level of Evidence: Therapeutic Level II. See Instructions to Authors for a complete description of levels of evidence.