How long should acute anterior dislocations of the shoulder be immobilized in external rotation

Background: Immobilization of the shoulder in external rotation has been shown to reduce the risk of recurrence after traumatic anteroinferior shoulder dislocation. It remains unclear how duration of immobilization affects labral coaptation.Hypothesis: Immobilization of the shoulder in 30° of external rotation for 5 weeks allows better coaptation of the anteroinferior labrum than does an immobilization period of 3 weeks.Study Design: Cohort study; Level of evidence, 2.Methods: Twenty-two patients with traumatic anteroinferior dislocation of the glenohumeral joint were included in this study. Patients were divided into 2 groups. Group 1 consisted of the initial 11 patients (mean age, 37.4 years) immobilized for 3 weeks; group 2 consisted of the subsequent 11 patients (mean age, 29.7 years) immobilized for 5 weeks in 30° of external rotation. With use of magnetic resonance imaging, displacement and separation of the glenoid labrum and anterior joint effusion were assessed in different arm positions (interna...