Sternoclavicular (SC) joint separations is an uncommon sprain of the ligaments at the joint between the sternum (breastbone) and the clavicle (collarbone). When ligaments are overstretched, they becomes taut and give way at their weakest point, either where they attach to the bone or within their mid-substance. The resulting injury may range from a minor sprain with no displacement of the bones to a more severe injury in which the clavicle completely loses contact with the sternum. The clavicle may move outward (anteriorly) to become more prominent, causing a bump on the chest or backward behind the sternum (posteriorly). Surgery is usually reserved for those with posteriorly displaced SC sprains. In these cases, the clavicle moves backwards towards the neck and can cause compression of the vital structures in the neck (airway, voice box, or blood vessels to the arms or head). This is usually an emergency that requires surgery to reduce the posteriorly displaced SC joint separation. Rarely, surgery to reconstruct the sternoclavicular ligaments is needed for those with chronic pain who have not recovered after four to six months of conservative treatment.
Majority of sternoclavicular injuries are anterior and treated non-operatively. Surgery to attempt to repair or reconstruct the sternoclavicular ligaments has limitations and is avoided if possible. For posterior sternoclavicular dislocations, careful surgical reduction of the clavicle is important to prevent injury to adjacent vascular structures and reconstruction of the ligaments is not always required. If symptomatic instability of the joint requires, surgical reconstruction is performed using a tendon graft (usually a hamstring tendon from the knee) to replace the torn ligaments. The repair/reconstruction can also be reinforced using strong sutures to help maintain the proper alignment of the bones at the sternoclavicular joint while the repaired or reconstructed ligaments heal.