Posterior fracture-dislocations often remain undiagnosed at initial medical attendance. In dislocation, the head of the humerus extends beyond the glenoid to form a zone of impaction, which “fixes” it. The injury is almost unidentifiable in standard frontal X-ray images. Meanwhile, continued fixation of the humerus in the state of posterior dislocation leads to a rapid progression of the traumatic impaction over up to 50% of the articular surface area. The associated damage to the articular lip of the scapula, rupture of the rotator cuff muscles, symptoms of shoulder instability after relocation, and severe pain syndrome require advanced treatments for this type of injury. Here we report a clinical case of anatomical neck fracture of the humerus with displaced consolidation, combined to posterior dislocation. To avoid subacromial impingement, instead of correcting the position of the head, we abandoned the reposition and performed an osteotomy with distal displacement of the greater tubercle of the humerus.