A 29-year-old male presents to the Emergency Department after a fall and landing on the left shoulder. Patient reports left medial clavicle/upper sternum pain and, on examination, has a painful left medial clavicle, overlying swelling, antalgic and limited movement of the left shoulder. No further injuries.
An AP radiograph of the left clavicle was the initial investigation and no fracture or dislocation was reported (Figure 1). The radiograph did not have both clavicles within the image and is an example of false negatives with reporting when only using limited views.
With a continued high index of suspicion for injury a computed tomography (CT) was ordered to further differentiate the pathology. A non-contrast CT scan of the left shoulder demonstrated a posterior dislocation of the left sternoclavicular (SC) joint with associated 15mm posteromedial displacement (Figures 2, 3 and 4). The non-contrast CT also revealed indentation of the transversing left brachiocephalic vein and associated stranding of the superior mediastinum adjacent to the aortic arch great vessels. In light of the potential for life-threatening injuries with posterior dislocations and the patient’s findings, a CT angiography of the chest was completed. Reassuringly, this scan was negative for mediastinal complications.
As little as 3% of shoulder girdle injuries are sternoclavicular (SC) dislocations [1,2]. The SC joint is a saddle-shaped synovial joint that links the axial and upper limb skeletons [3]. The SC joint has the potential to dislocate anteriorly and posteriorly at a ratio of 9:1, due to a weaker anterior SC ligament [1,2]. Anatomically, a posterior dislocation has the potential to disrupt the closely associated mediastinal structures (i.e., neurovascular, oesophageal and tracheal anatomy) with potentially life-threatening sequelae [1,3]. Up to 30% of posterior dislocations have associated mediastinal injuries, which have correlated mortality rates of 3%–4% [4].
Often, the clinical presentation occurs in the context of high-impact trauma [5]. Common examination findings of medial clavicle pain, antalgic and reduced shoulder movement and a palpable step at the SC joint [5,6]. Compression-type symptoms of “dyspnoea, dysphagia and paraesthesia down the arm” [6] should heighten suspicion for SC dislocation, more specifically, posterior dislocation [1,6].
Radiographs, even dedicated clavicle views, have low sensitivity [1,7]. Instead, with a high index of suspicion, it is advisable to complete a CT non-contrast as it allows for superior high-resolution images, 3D reconstruction, and a definitive diagnosis [1,8] (Figures 3 and 4]. CT will also highlight secondary injuries associated with SC dislocations. CT, in the case of SC dislocation, is both diagnostic and instrumental for operative planning. Moreover, a delay in CT imaging can delay diagnosis [6]. Chest radiographs still have a place in the initial investigation as they highlight critical pathologies (e.g., pneumothorax, pneumomediastinum, haemopneumothorax, etc) that require urgent intervention [1,9].
The management of anterior versus posterior dislocations differs. Anterior dislocation is predominantly managed conservatively with closed reduction. Surgical management tends to occur in cases of ongoing pain or instability [1]. For lower-risk posterior dislocations (patients without signs of compression and attending within days of the injury), there is the possibility of attempting closed reduction. However, the majority need surgical management (open reduction and stabilisation) [1]. If there is also associated mediastinal injury, cardiothoracic surgery oversight or involvement is needed [1].
Take-Home Message / Teaching Points
Posterior dislocation of the sternoclavicular joint
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According to the provided X-ray and CT images, the following key features are observed:
Based on the patient's history of trauma (fall onto and impacting the shoulder) and the imaging findings, the following diagnoses should be considered:
Considering the patient's age, mechanism of injury, local pain and restricted motion on examination, and the CT findings showing posterior displacement of the medial end of the left clavicle, the most likely diagnosis is:
Posterior dislocation of the left sternoclavicular joint
It is recommended to closely monitor for any signs of mediastinal compression, such as difficulty breathing, difficulty swallowing, or abnormal sensation in the affected upper extremity. Further assessment of potential involvement of the heart, lungs, and esophagus should be performed if necessary.
Once the joint is relatively stable, rehabilitation training can gradually begin, following the FITT-VP principles (Frequency, Intensity, Time, Type, Progression, and individualization).
Safety note: If you experience significant pain, a feeling of joint instability, or chest tightness or difficulty breathing, discontinue exercise immediately and seek medical attention.
Disclaimer: This report is provided for reference purposes in medical analysis and cannot replace in-person consultation or professional medical advice. If you have any questions or changes in your condition, please seek medical attention promptly and follow the advice of a specialist physician.
Posterior dislocation of the sternoclavicular joint
