Glena-humeral dislocation is rare. More than the half of those dislocations is unremarked because the diagnostic is not an emergency. A delayed diagnostic alters the functional prognostic and sometimes forces to do a complex surgery with complications whose success rate remains uncertain. We report a case of inveterate posterior shoulder dislocation on a 42-year-old adult occurred during a sport accident and treated by sub-scapulars transfer (modified Mac Laughlin’s technical). The aim of this article is to highlight this pathology to ameliorate its diagnostic rate indeed prognostic. Our diagnostic approach and injury, noticed during surgery and therapeutic propositions, are described at the light of literature data on this subject.