[Dislocation fractures of the shoulder. Special status and therapeutic concepts]

Shoulder dislocations associated with a displaced fracture of the humeral head or glenoid require different treatment than shoulder dislocations without fracture. If the humeral head is fractured, two possible complications must be considered:impairment of the subacromial gliding mechanism and insufficient blood supply to the humeral head. In glenoid fractures, instability may be induced. The degree of instability depends on the size of the fragment. In fractures of the humeral head, in particular of the greater tuberosity, we differentiate between the so-called en bloc fracture and the so-called supra-spinatus avulsion fracture. In "en bloc" fractures, one has to be aware that displacement of the fragment can occur not only in the superior direction but in the posterior direction as well. Posterior displacement is displayed radiologically by the "tangential" view. Both the duration of pain and range of motion depend on the amount of displacement of the fragment. Displacement exceeding 3 min in one direction should be reduced surgically in the active patient. For operative treatment of a displaced "en bloc" fracture, we recommend closed reduction and percutaneous screw fixation performed under regional anesthesia. "Supraspinatus avulsion fractures" ought to be treated like rotator cuff tears because there is no possibility of the small fragments healing due to their placement on the joint cartilage. In fracture dislocations, the blood supply of the humeral head is seriously jeopardized if the fracture is situated in the anatomical neck, whereas this is not the case in a fracture of the surgical neck. The number of displaced fragments allows a prediction concerning the survival of the articular segment of the humeral head.(ABSTRACT TRUNCATED AT 250 WORDS)