The sternoclavicular joint is the most frequently moved nonaxial joint of the body because almost any movement of the upper extremity is transferred proximally to this joint. It also has the least amount of bony stability of any major joint because less than half of the medial end of the clavicle actually articulates with the upper sternum. Joint stability therefore depends on the integrity of the surrounding ligaments, which give the sternoclavicular joint surprising strength. As a result, the majority of injuries to this area are simple sprains, dislocations being uncommon.
A sprain of the sternoclavicular joint can result from the shoulder being forced forward suddenly or from a medially directed force applied to the shoulder. Pain and swelling are localized to the joint, and treatment is symptomatic with ice, sling, and analgesics. Differential diagnosis should include consideration of septic arthritis, especially in intravenous drug abusers.
Sternoclavicular dislocations are uncommon, accounting for only 3 percent of a series of 1603 shoulder girdle injuries. Dislocations usually result from motor vehicle accidents or sports injuries, but spontaneous dislocations have been reported. Posterior sternoclavicular joint dislocations are much less common than anterior dislocations. A posterior dislocation may result from a direct blow or from an indirect force to the shoulder if the shoulder is rolled forward at the time of impact. An anterior sternoclavicular joint dislocation may result from the same indirect force if the shoulder is rolled backward at the time of impact. Of note is that the medial clavicular epiphysis is the last epiphysis of the body to appear radiographically (age 18) and the last to close (age 22 to 25). As a result, physeal injuries in this age group can easily be misdiagnosed as a dislocation.
Patients with a sternoclavicular joint dislocation have severe pain that is exacerbated by arm motion and when in the supine position. The shoulder appears shortened and rolled forward. On examination, anterior dislocations have a prominent medial clavicle end that is visible and palpable anterior to the sternum. In posterior dislocations, the medial clavicle end is less visible and not palpable, and the patient may have signs and symptoms of impingement of the superior mediastinal contents (Fig...263z1). Routine radiographs may not be diagnostic although specialized views or tomograms may be helpful. Computed tomography (CT) is the imaging procedure of choice.
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FIG. 263-1. The relationship of the sternoclavicular joint to adjacent structures. RSV, right subclavian vein; RIA, right innominate artery; LCCA, left common carotid artery; LSA, left subclavian artery; LSV, left subclavian vein.
Closed reduction of anterior sternoclavicular joint dislocations is usually attempted with the patient supine and with a sandbag or pad between the shoulders. Direct pressure over the clavicle may reduce the dislocation.The patient is usually discharged in a figure-of-eight clavicle harness. Unfortunately, many anterior dislocations prove unstable and recur as soon as direct pressure is released. Patients may subsequently undergo open reduction, or the position of the deformity may be accepted and no further treatment rendered.
In posterior dislocations, life-threatening injuries to adjacent structures may result in a pneumothorax or in compression or laceration of the great vessels, trachea, or esophagus. Local swelling may obscure any deformity, and routine radiographs are often not conclusive, making diagnosis difficult. Additional injuries should be aggressively sought and addressed. Orthopedic consultation for stabilized patients may attempt closed reduction, with thoracic surgical backup. A towel clip is often used to grasp and pull the medial clavicle forward and back into place. Open reduction may be necessary.
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