Case Report: Revision surgery for a missed posterior dislocation of the humeral head in a shoulder fracture-dislocation and literature review.

Background: Posterior shoulder dislocation is uncommon and therefore prone to being missed. When accompanied by a proximal humeral fracture, complex fracture lines may obscure the radiographic signs of dislocation. Inadequate standardization of the imaging workup may consequently result in inappropriate management and treatment failure. Case presentation: We report a young patient in whom posterior shoulder dislocation was missed at the initial assessment because axillary and scapular Y-view radiographs were not obtained and the available imaging was insufficiently interpreted. The dislocation persisted after the index operation. Revision surgery was performed on postoperative day 9 and resulted in a favorable 5-year outcome, with no radiographic evidence of humeral head avascular necrosis or post-traumatic osteoarthritis and near-complete recovery of shoulder function. Conclusion: Occult posterior shoulder dislocation should be strongly suspected in patients with complex proximal humeral fractures after high-energy trauma. Obtaining axillary or scapular Y-view radiographs, together with a systematic CT-based assessment, is essential. Even after early treatment failure, targeted revision surgery combined with structured rehabilitation may still achieve a satisfactory long-term outcome in young patients.