AIM The successful operative stabilization of the shoulder joint is a demanding surgical procedure. The causality of shoulder instability is complex with in some cases multiple lesions in different anatomical structures. The surgeon has to understand the complexity of factors causing instability in order to be therapeutically successful. The aim of the study was to document the intraoperative pathology in revision instability surgery. METHOD 46 patients with recurrent postoperative instability were included (8 female, 38 male, follow-up > 12 months). After diagnostic arthroscopy an open revision surgery was performed in all cases. RESULTS In 19 cases (40%) an insufficient surgical procedure was performed (inadequate capsular shift with worn out labral tissue). Selection of an incorrect surgical technique was the reason for revision in 12 patients (25%). Anamnestically 5 patients reported a re-injury, whereas objectively only one patient described an adequate trauma. The most frequent finding was an open rotator interval (persisting Foramen Weitbrecht), which was seen in 22 cases (46%). CONCLUSION A stable range of motion of the shoulder is achieved by a variety of different factors, which leads in most instances to a combination of pathological changes in case of a dislocated shoulder. To understand the contributing factors of an instable shoulder joint is a necessity to carry out a successful surgical procedure.