Posterior Sternoclavicular Joint Dislocation
Cyd Charisse Williams, MD
Emergencies Series Editor: Warren B. Howe, MD
THE PHYSICIAN AND SPORTSMEDICINE - VOL 27 - NO. 2 - FEBRUARY 1999
In Brief: Posterior sternoclavicular (SC) joint dislocations are rare but can have serious complications, such as hemorrhage or tracheal rupture or compression. Described here is the case of a 21-year-old college football player who fell on his right shoulder and, on the basis of a physical exam and plain radiographs, was first diagnosed as having an apophyseal injury of the SC joint. Increased shoulder and throat pain led to further evaluation; a CT scan revealed a posterior SC joint dislocation. Knowing the signs and symptoms that characterize these dislocations, the role of CT in diagnosis, and the techniques of emergency reduction can prevent or minimize serious complications.
Sternoclavicular (SC) injuries are common in sports, especially in football, and most are anterior in nature. Though posterior SC joint injuries are rare, their consequences can be life-threatening. A case report illustrates the difficulty of diagnosing posterior SC joint dislocations and the need for a high index of suspicion in the evaluation of all SC joint injuries.
A 21-year-old college wide receiver who was participating in a summer football camp was tackled as he attempted to catch a touchdown pass in the end zone. He fell on his right shoulder with his arm flexed and adducted. He lay face down and motionless until he was rolled over for examination, when the athletic trainer and the athlete reported hearing a pop.
The player could not sit or stand up without assistance because of pain in his right arm and shoulder. He had no cardiorespiratory symptoms such as shortness of breath, palpitations, or chest pain. He reported a "funny feeling" in his throat, which became painful within about 40 minutes.
The physical examination revealed no clavicular or acromioclavicular joint tenderness or deformity. No edema, erythema, or asymmetry of the SC joint was evident. A more detailed examination of the shoulder could not be completed because of shortness of breath with right arm abduction. Compared with the left hand, his right hand had slightly less grip strength but normal sensation.
The athlete's arm was placed in a sling, and he was transported to a sports medicine clinic for further evaluation. A radiographic serendipity view of the shoulder revealed no displacement of the clavicle, and he was diagnosed as having an apophyseal injury. The patient was treated with a sling and nonsteroidal anti-inflammatory drugs and sent home with instructions to report to the training room for follow-up the next day.
Worsening symptoms. Three hours later, he reported worsening shoulder and throat pain and returned to the clinic for reexamination. The differential diagnosis included an epiphyseal Salter (apophyseal) injury of the clavicle, a fractured clavicle, a posterior SC joint subluxation, an anterior or posterior SC joint dislocation, and a fractured scapula. He was sent to a nearby hospital for a computed tomography (CT) scan of the shoulder (figure 1a), which revealed a posteriorly displaced right clavicle behind the sternum with an intact apophysis, indicating a true posterior SC joint dislocation. Compression of the brachiocephalic vein was also evident.
Treatment. Because the CT scan excluded internal injuries, the patient was treated with closed reduction of the right SC joint. A repeat CT scan (figure 1b) revealed proper alignment of the right and left clavicles with the sternum and no compression of the brachiocephalic vein. He was placed in a figure-eight brace with an infrascapular neck roll 24 hours a day for 4 weeks. He was instructed to avoid contact sports for 6 weeks. The player subsequently quit playing football and was lost to follow-up.
Anatomy and Incidence
SC joint anatomy. The articular surface of the medial clavicle is much larger than the corresponding surface of the sternum, making the surfaces relatively incongruent, but several strong ligaments give the joint stability (figure 2). Underlying structures include the brachiocephalic, jugular, and subclavian veins; brachiocephalic, carotid, and subclavian arteries; trachea and esophagus; lungs and pleurae; and the brachial plexus.
Epidemiology. The strength of the SC joint ligaments probably accounts for the low incidence of SC joint dislocations. Only 3% to 5% of shoulder injuries occur at the SC joint, and most are physeal injuries rather than true dislocations. Anterior dislocations outnumber posterior dislocations by up to 20 to 1 (1), so true posterior dislocations of the SC joint, as in the case above, are rare.
SC joint injuries are most commonly caused by trauma involved in motor vehicle accidents and sports, particularly football.
Mechanism of injury. The most typical mechanism for posterior SC joint dislocations in sports is a lateral compression of the shoulder girdle resulting from a fall on the shoulder when the arm is in forward elevation and flexion, a position somewhat different from that of the present case. The resulting force disrupts the costoclavicular and SC ligaments (figure 3).
Evaluation and Treatment
The three types of injury. Injuries to the SC joint ligaments fall into three categories, which correspond to characteristic physical findings and treatments (table 1). Types 1 and 2 are mild or moderate sprains that generally do not have serious sequelae, while type 3 injuries are severe sprains that involve complete ligament disruption and either anterior or posterior joint dislocation.
Signs and symptoms. The typical signs and symptoms of a posterior SC joint injury include pain with shoulder compression or movement and pain, swelling, and asymmetry at the SC joint (decreased prominence of the medial clavicle on the affected side (2)). However, signs and symptoms can vary, as the case demonstrates.
Other possible indications include breathing difficulty or shortness of breath, a choking sensation or tight feeling in the throat, difficulty swallowing, venous engorgement of the ipsilateral arm, ipsilateral paresthesias, pneumothorax, a head tilt toward the affected side, and shock. One or more of these may be present and may progress over time, depending on the structures being impinged.
Imaging studies. Since many SC joint injuries may be difficult to detect solely by clinical findings, radiographs are required. An anteroposterior view is less useful than the serendipity view, which is taken with 40° of cephalic tilt. In this view, the clavicle is more likely to be seen projecting above the horizontal plane in an anterior dislocation and below the horizontal in a posterior dislocation. However, the difference can be subtle. In the present case, radiographs initially read as normal retrospectively revealed that the clavicle was slightly displaced below the horizontal. Hobb's view—a 90° cephalocaudal lateral radiographic view of the SC joint—can also be useful.
A CT scan with 3-mm axial images shows musculoskeletal structures more effectively than magnetic resonance imaging and should be obtained for a definitive diagnosis (3).
Closed and open reduction. Posterior SC joint dislocations require closed or open reduction under general anesthesia. A closed reduction should not be performed until the status of the underlying structures mentioned above is known. If these are seriously compromised, surgery is indicated.
In the event of airway obstruction, however, urgent reduction is indicated and can be done by direct or indirect retraction of the shoulder girdle. If significant swelling and muscle spasm have not yet occurred, reduction may be achieved by placing a knee between the seated athlete's scapulae and pulling back on his or her shoulders. Alternatively, with the patient supine on a sandbag or rolled-up towel, applying lateral traction to the abducted arm as it is gradually extended (figure 4a) can result in reduction. The clavicle may have to be manually dislodged from behind the manubrium using a surgical towel clip (figure 4b). Reduction is often evidenced by a snap or a pop.
An open reduction includes a ligament repair with reconstruction. Because of cartilaginous damage, resection may be needed to stabilize the joint to the front rib or the sternum. Open reduction with fixation using Kirschner wires or Steinmann pins is not recommended because of the risk of hardware migration (4).
Complications. Posterior SC joint dislocations may be rare, but they can have life-threatening consequences if they are missed. Complications have been noted in 25% of cases (5); these have included hemorrhage and tracheo-esophageal fistulas that resulted in death up to 4.5 years after the original injury. Pneumothorax, hemothorax, brachial plexus injuries, and hoarseness are other complications that have been reported (6). Similar complications can occur after an open reduction.
Patients suspected of having a posterior SC joint injury may have equivocal or normal radiographs. Given the potential danger of this injury, a CT scan should be obtained to make a definitive diagnosis in a patient who has suspicious symptoms.
Dr Williams practices pediatric, adolescent, and sports medicine at Crossroads Medical Centers, PA, in Chaska, Minnesota, and is a team physician for USA Track and Field. Dr Howe is the team physician at Western Washington University in Bellingham and an editorial board member of The Physician and Sportsmedicine. Address correspondence to Cyd Charisse Williams, MD, 3000 N Chestnut, Suite 120, Chaska, MN 55318.