Approach to the Multitrauma Patient With Sternoclavicular Joint Dislocation
Case
A 28-year-old woman was brought to the ED by emergency medical services for evaluation of injuries sustained from a high-speed, rollover motor vehicle collision (MVC), during which she was partially ejected from the passenger front seat. The patient did not experience any loss of consciousness following the MVC. At presentation, she was oriented to place and time, and actively complained of bilateral clavicular pain (which she noted was worse on her right side) as well as right forearm pain.
The patient’s vital signs upon arrival were: heart rate, 94 beats/min; respiratory rate, 24 breaths/min; blood pressure, 107/84 mm Hg; and temperature,
The focused assessment with sonography for trauma examination was negative. In addition to the bilateral clavicular and right forearm pain, the patient also had tenderness bilaterally over the sternoclavicular joints (SCJ) and the right midclavicle, though there were no obvious deformities. Laboratory studies were within normal limits, with the exception of an elevated white blood cell count of 21 x 109/L.
Initial plain radiographs showed a normal chest X-ray (CXR) and right forearm fracture. 
Orthopedic services were contacted and, with cardiothoracic surgery services readily available, the patient underwent an open reduction and internal fixation of the unstable SCJ. After surgical intervention, the patient experienced motor and sensory dysfunction, and a magnetic resonance imaging (MRI) study of the upper right extremity was ordered, which revealed brachial plexus injury secondary to hematoma and soft-tissue contusion in the right supraclavicular region. The patient remained in the hospital until postoperative day 3, at which time she was discharged home.
Three weeks after discharge, the patient followed up with the orthopedist for further surgical intervention of the comminuted distal forearm fracture. At that time, she had no further neurological or motor deficits from the upper extremity hematoma. However, 4 months after the MVC, she presented to the ED for evaluation of continued right shoulder pain. During this visit, X-ray studies confirmed posttraumatic arthritis; otherwise, the workup was negative for any further sequela or injury.
Discussion
Sternoclavicular joint dislocation is a rare traumatic injury, accounting for less than 3% of shoulder girdle injuries.1-4 Dislocations of the SCJ, which may be anterior or posterior, superior or inferior, are typically due to an MVC or athletic injury involving great force.5
Although an injury involving mediastinal compression such as a posterior SCJ dislocation can be fatal if not treated early, these dislocations are typically not detected in a multitrauma patient until the secondary survey.6 A missed diagnosis of posterior SCJ dislocation carries a mortality rate of 3% to 4% due to the potential for retrosternal injuries.4,6 Unfortunately, SCJ dislocations can be an easily overlooked injury in the multitrauma patient, as plain radiographs are difficult to interpret and physical examination findings other than tenderness may not always be present.5-7
Anatomy
The SCJ is comprised of the manubrium’s clavicular notch, the medial end of the clavicle, and the cartilage of the first rib.3 The capsular ligaments cover the anterior and posterior parts of the joint and offer stability along with the costoclavicular and interclavicular ligaments. Since the surrounding ligaments provide strong support to the joint, an incredible amount of force is needed for a dislocation to occur.
The clavicle is the first long bone in the body to ossify, and it does so in utero; however, the epiphysis of the medial clavicle is the last to ossify, and it does not fuse with the body of the clavicle until the early-to-mid-third decade of life. Since younger patients are therefore more prone to physeal fracture than joint dislocation, it is imperative to keep this as part of the differential in patients younger than age 25 years.1,3,8-10
