A prospective randomized trial is needed to determine whether in young patients (16-30 yrs of age) following reduction of a first-time traumatic anterior shoulder dislocation, does EMERGENT (<4 hours post reduction) immobilization of the affected shoulder in external rotation reduce the rate of recurrent instability experienced within 12 months versus emergent immobilization in a traditional internal rotation sling? Eligible patients will be randomly allocated to the sling or ER brace. The results of this study will provide the best evidence for choosing emergent immobilization for shoulder dislocations.