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Dislocations of the sternoclavicular joint (SCJ) are uncommon due to the strength of the supporting ligaments. Anterior dislocations are nine times more frequent than posterior dislocations. Posterior dislocations are clinically more important due to the potential for injury to underlying structures. SCJ dislocations typically occur from motor vehicle crashes and sports injuries. Examination findings of an anterior SCJ dislocation include tenderness and prominence of the proximal clavicle from the sternum. The arm is often held in adduction. Posterior SCJ dislocations may be more difficult to identify. Pneumothorax, great vessel, tracheal, and esophageal injuries often accompany posterior SCJ dislocations. Pain and depression of the medial clavicle relative to the sternum may be seen. Superior and inferior dislocations may also be seen. CT scan through the SCJ is the best diagnostic study to evaluate this injury.
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Management and Disposition
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Orthopedic follow-up is required. Closed reduction of anterior SCJ dislocations is performed by placing the patient supine with a sandbag between their shoulders and placing downward pressure directly over the clavicle. A figure-of-eight clavicle harness is applied. Recurrence is common. Closed reduction of posterior SCJ dislocations may be attempted by an orthopedic surgeon by placing a towel clip around the medial clavicle and pulling the clavicle forward. Open reduction is often necessary.
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While it typically requires a tremendous force to cause an SCJ dislocation, spontaneous dislocations have been reported.
In the apical lordotic radiograph (serendipity view), the clavicular head will be higher than the unaffected side in anterior and lower than the unaffected side in posterior dislocations.
One-fourth of posterior SCJ dislocations result in mediastinal injury; they always require reduction.