Sternoclavicular dislocation is a type of injury in which the collarbone, or clavicle, becomes separated from its attachment to the sternum, or breastbone. This could be caused by a violent blow to the shoulder. A sternoclavicular dislocation is a relatively uncommon form of shoulder injury because the sternoclavicular joint, between the sternum and clavicle, is reinforced by a number of strong bands of tissue called ligaments, as well as a capsule surrounding the joint. Motor vehicle accidents, sporting injuries and falls may all give rise to sternoclavicular dislocation. If a dislocation cannot be managed by manipulating the joint back into position, surgery may be required.
Most often, a sternoclavicular joint dislocation is what is known as an anterior dislocation, where the free end of the clavicle ends up in front of the sternum. This is usually the result of a force being applied to the front of the shoulder, rotating the shoulder backward and tearing the clavicle away from the sternum. Posterior dislocations are less common and may be caused by a force hitting the shoulder from behind, rupturing the joint and driving the clavicle behind the sternum. Occasionally, posterior dislocation is the result of a force directly hitting the front of the clavicle and pushing it back. The risk with a posterior dislocation is that the end of the clavicle could damage important structures which lie under the sternum, such as the lungs, esophagus, and major blood vessels.
Symptoms associated with sternoclavicular dislocation include pain, which is typically severe, and deformity of the shoulder. The discomfort is usually worse with a posterior dislocation and, for both anterior and posterior dislocations, moving the arm leads to an increase in pain. Depending on the injury, there may be symptoms, such as breathlessness and swallowing difficulties, associated with other structures which have been damaged. In the case of an anterior dislocation, there may be a visible lump, which represents the end of the clavicle protruding forward.
Treatment of sternoclavicular dislocation may not be necessary in the case of an anterior dislocation, as some injured joints may simply be left as they are and allowed to heal. In other cases, what is known as a closed reduction may be carried out. This involves moving the joint back into position by hand, a procedure which may require a general anesthetic due to its painful nature. Closed reduction is more likely to be successful for posterior dislocations but, if the technique fails, sternoclavicular surgery may be necessary in order to avoid future complications. Surgery allows the dislocated joint to be repositioned from the inside and fixed in place for stability.