Background It is still not clear which method is the most efficient for treating primary traumatic anterior shoulder dislocation. Immobilization in external rotation has become increasingly discussed within the last 10 years. The aim of this study was to evaluate the rate of recurrence and clinical outcome of the immobilization in external rotation after primary traumatic anterior dislocation within a midterm period of 5 years. Additionally, a summary of literature is given according to the present knowledge of this issue.Methods From May 2004 to May 2006, 28 patients with primary traumatic anterior shoulder dislocations were included in a prospective MRI-controlled study. After a follow-up of 5 years, the recurrence rate and clinical outcomes of the patients were evaluated using clinical scores (Constant and Murley score, Western Ontario Shoulder Instability Index, Rowe score).Results After 5 years, 26 patients (93 %; males, n = 25; female, n = 1; mean age, 29.3 years) were interviewed concerning re-dislocations. In the meantime, four patients (15 %) experienced a re-dislocation (ø 12.2 months) after the end of the immobilization. Overall, 21 patients (75 %) were included in a clinical follow-up (CM score: ø 92.8 points; Western Ontario Shoulder Instability Index: ø 87 %; Rowe score (in 17 patients): ø 94.2 points). Upon clinical examination, unidirectional anterior instability was found in one patient, which corresponds to an overall instability rate of 19 % within the examined patient population including the re-dislocations.Conclusions Immobilization in external rotation shows satisfactory results after 5 years in regard to recurrence and instability rates and clinical outcomes. The data show that with immobilization in external rotation, re-dislocations occur within the first 2 years.