Dislocation of the glenohumeral joint is the most common traumatic joint dislocation. The usual treatment of first time traumatic anterior dislocation of the shoulder is reduction followed by immobilization in a sling for a period of one to three weeks. The incidence of recurrence is high and age at the time of primary dislocation is the chief prognostic factor in determining the risk of recurrence. There is no agreement according to the effect of immobilization,neither to the length of immobilization time. The Bankart lesion with avulsion of the inferior-anterior capsulolabral complex is almost invariably present in patients with anterior shoulder dislocation. Recent and ongoing studies by Eijii Itoi et al,Akita university Japan, gives evidence of the immobilization with the arm held in external rotation may reduce the risk of subsequent instability by approximating the Bankart lesion to the neck of the glenoid giving a more anatomical healing. We have started a prospective randomized study. The patients are assigned to two groups with informed consent. One group are immobilized in internal rotation for 3 weeks and the second group are immobilized in external rotation for 3 weeks. We will compare the rate of relaxation between the groups. Because age is the main prognostic factor we use stratified randomization with two age groups: One group of patients aged between 16 and 24 years and one group aged between 25 and 40 years.The time of observation after initial treatment will be 2 years with follow up after 4 and 10 years. Eleven hospitals and two primary trauma care centers in Norway participate in the study. A subgroup of 50 patients are also planned to be examined with CT and MRI.