RETROSTERNAL
DISLOCATION OF THE CLAVICLE - By F. Harlan Selesnick,
M.D., Michael Jablon, M.D., From the Department of
Orthopaedic Surgery, Posterior dislocation of the sternoclavicular joint is a relatively rare injury and may be difficult to diagnose if it is not suspected. Cave found only one such injury in 1600 cases of trauma to the shoulder. Rowe and Marble found ten injuries to the sternoclavicular joint in their analysis of 1603 shoulder-girdle injuries, but only one was a retrosternal dislocation. When that dislocation does occur, early diagnosis is important because closed reduction is seldom successful after forty-eight hours. Moreover attendant complications, including a tracheal tear of trauma to the great vessels, may be fatal. Conventional radiographs of the sternoclavicular joint are often difficult to interpret, and authors have differed in their opinions on how best to diagnose a dislocation of that joint. Because of the rarity of the injury and the variety of clinical manifestations, even an experienced examiner may miss the diagnosis unless a high index of suspicion exists and appropriate diagnostic radiographs are made. The purpose of this paper is to again bring to the attention of the reader the serious nature of the injury and the potential difficulties of establishing the diagnosis of achieving reduction. We have reviewed the relevant literature and he management of the cases of four patients treated recently at the Michael Reese Hospital and Medical Center. Anatomy The upper limb articulates indirectly with the axial skeleton through the sternoclavicular articulation. It is a diarthrodial joint that is composed of the sternal end of the clavicle, the cartilage of the first rib, and the lateral aspect of the manubrium. The incongruent osseous surfaces are separated by a flat, circular articular disc. Joint stability is maintained by the capsule and by the costoclavicular and sternoclavicular ligaments. Anteriorly the capsule is thickened by the anterior sternoclavicular ligament and posteriorly, by the thicker posterior sternoclavicular ligament, both of which attach the medial end of the clavicle to the manubrium of the sternum. The costoclavicular ligament connects the medial portion of the cartilage of the first rib with the costal tuberosity on the undersurface of the clavicle and opposes the pull of the sternocleidomastoid muscle. The sternoclavicular joint permits limited motion in all directions. The great vessels, trachea, and esophagus lie posterior to the sternoclavicular joint. The weaker anterior part of the capsule is more easily injured than the posterior part, and that explains in part why anterior dislocation is much more common than posterior dislocation. Paterson stated that anatomical variations such as an increase in the angle of the sternoclavicular joint to the sagittal plane of the body may be a contributing factor to dislocation. The clavicle ossifies early in fetal development but the secondary center at the sternal end of the clavicle does not appear before the eighteenth year and may not unite until the twenty-fifth year. This persistence of a separate secondary center of ossification is of extreme importance when a patient sustains an injury before epiphyseal closure has occurred. In patients who are less than twenty-five years old, most retrosternal dislocations of the clavicle are found to be Salter-Harris Type-I epiphyseal fractures with the epiphyseal plate remaining attached to the medial end of the clavicle. END OF ABSTRACT OF REPORT |