Posterior shoulder dislocations and fracture-dislocations.

Posterior shoulder dislocations and fracture-dislocations are uncommon injuries that most often occur during seizures or as a result of high-energy trauma. Despite advances in imaging, they are frequently diagnosed late. Detection is facilitated by heightened clinical suspicion of the injury in high-risk individuals together with appropriate radiographic investigation. A wide variety of operative techniques, ranging from simple closed reduction to soft-tissue and bone stabilization procedures to prosthetic arthroplasty, are available to treat these injuries. Selection of the most appropriate treatment option is complex and multifactorial. Because of the rarity of these injuries, evidence-based treatment protocols are difficult to devise. Good functional outcomes are associated with early detection and treatment of isolated posterior dislocations that are associated with a small osseous defect and are stable following closed reduction. Poor prognostic factors include late diagnosis, a large anterior defect in the humeral head, deformity or arthrosis of the humeral head, an associated fracture of the proximal part of the humerus, and the need for an arthroplasty.