Bilateral nontraumatic anterior acromioclavicular joint dislocation. A case report.

An incidental finding of bilateral nontraumatic anterior acromioclavicular joint dislocation was made in a 14-year-old boy with spastic hemiparesis. Acromial processes were dislocated anterior to the distal clavicles, with characteristic radiographic findings. The dislocation is termed "anterior" because the clavicle is anatomically more proximal than the acromion. Anterior acromioclavicular joint dislocation usually is associated with significant trauma. There was no history of trauma in this case. Localized laxity of the acromioclavicular and coracoclavicular ligaments was the presumed cause of this condition, because there was no visible osseous abnormality. Since the patient was asymptomatic, no treatment was indicated.