A 32-year-old woman presented with left shoulder pain after she was hit by a car while crossing the street. Her forehead hit the windshield, and she flew off the car, landing on her left side.
She had a forehead hematoma and abrasion as well as severe pain with range of motion of her left shoulder. She had no obvious deformity to her shoulder, but she was holding it close to her body and would not let anyone move it. She had diffuse chest wall and abdominal pain. Her vital signs were normal.
A bedside FAST exam did not show free fluid or obvious intra-abdominal or intrathoracic injury. Chest and shoulder x-rays were normal without acute injury.
What injury does this patient have?
Find the diagnosis and case discussion on the next page.
Diagnosis: Posterior Sternoclavicular Joint Dislocation
Given the mechanism of her injury and severe pain, CT imaging of her head to her pelvis was ordered, and it identified a posterior sternoclavicular joint dislocation with compression of the brachiocephalic vessels. The sternoclavicular joint is an unstable joint that relies solely on ligamentous attachments, and is the only connection of the axial skeleton to the upper extremity. Dislocations are rare and make up less than three percent of all traumatic sternoclavicular joint injuries. (J Am Acad Orthop Surg. 2011;19:1.) The clavicle is the first bone to form, but its medial end is the last to fuse around age 25. Injuries that occur before that age should be evaluated for physeal fracture rather than simple dislocation. Anterior dislocations are almost nine times more common than posterior ones. (World J Orthop. 2016;7:244; http://bit.ly/2XbU2lh.)
High-force injuries to the shoulder can cause anterior or posterior dislocations depending on the direction of the force. An anterior dislocation can occur if the force applied to a shoulder is rotated away from the body. A posterior dislocation can occur if the force applied is rotated into the body, by direct force to the sternoclavicular joint or when a patient's chest hits a steering wheel. Posterior dislocations have a mortality rate of three to four percent with an associated 30 percent risk of neurovascular, tracheal, or esophageal injury. (World J Orthop. 2016;7:244; http://bit.ly/2XbU2lh.)
Anterior dislocations are easier than posterior ones to identify on physical exam, and they produce a painful, raised lump just lateral to the sternum. Posterior dislocations can be tricky because patients commonly hold the arm close to their body to prevent pain with movement of the shoulder joint. The indention of the posteriorly located clavicular head can be missed because of this positioning. Patients with posterior dislocations can also present with shortness of breath, trouble swallowing, paresthesia, and pulse deficits because of the mass effect or injury to mediastinal structures.
X-rays can be misleading. A standard chest or shoulder x-ray is not sensitive enough for sternoclavicular joint dislocations. A serendipity view can increase the sensitivity by angling the x-ray beam 45 degrees cephalad. CTA is best for imaging these dislocations, and can evaluate for associated injuries to the brachial plexus, great vessels, esophagus, trachea, and other mediastinal structures.
Anterior dislocations can be safely reduced with procedural sedation in the emergency department, but most posterior dislocations warrant consultation for OR reduction, which may be necessary if mediastinal structures are injured.
Our patient fell directly onto her shoulder, which was rotated into her body, resulting in a posterior dislocation of the clavicle. She was taken to the OR for closed reduction under general anesthesia. The team was unable to reduce the dislocation with abduction and traction, so percutaneous manipulation of the medial head of the clavicle using bone-grasping towel clamps was necessary to reduce it safely. The patient was placed in a shoulder immobilizer, and did well with no immediate complications.
This case highlights the high index of suspicion an emergency physician should have when a patient presents with severe shoulder pain after trauma but no obvious fracture on x-ray. Besides the well-taught concern for splenic or liver injury causing referred pain, be aware of sternoclavicular joint dislocation and its physical exam findings, imaging studies, and treatment.
Dr. Eutermoseris an assistant professor of emergency medicine at Denver Health and University of Colorado Hospital. Read her past columns athttp://bit.ly/EMN-QuickConsult.