[Posterior dislocation fracture of the shoulder]

Posterior dislocation fracture of the shoulder is a rare injury that often occurs in association with a grand mal seizure. Our aim with this paper is to emphasize diagnosis and therapy. In the past 5 years seven patients with nine posterior dislocation fractures were treated operatively. In six patients a grand mal seizure was the cause of the injury and in one a direct trauma. Three four-part fractures were found in two patients and six locked posterior dislocation fractures in five patients. Clinical examination in locked posterior dislocation fractures showed a lack of external rotation, and flexion was performed by movement of the scapula. Radiological examination demonstrated an overlapping of the contours of the humeral head and the glenoid and the "trough line". The operations were performed in the time between 4 h and 10 days later. Two of three four-part fractures (in one patient) were treated with hemiarthroplasties, and one was fixed with screws. Closed reduction was attempted in six shoulders but was possible only in one patient. In this patient a redislocation occurred 3 days later and a combined anterior and posterior approach was done. A fracture of the anatomical neck was produced in another shoulder. Six open reductions and stabilizations with screws were performed, and three times we fixed the subscapular tendon in the reversed Hill-Sachs lesion with anchor sutures. Patients after grand mal seizures may have a posterior shoulder dislocation, and clinical and radiological examination should be emphasized. In locked posterior dislocation we favour early open reduction, fixation of the subscapular tendon with anchor sutures in the reversed Hill-Sachs lesion and stabilization of the lesser tuberosity with screws.