Disclaimer: The following case is for education purposes only and does not depict any actual person or patient.
A 17-year-old male reports that he and his buddies were playing "rough touch" football in the street in front of their house, with no pads. During a full speed kick-off, his left shoulder made direct contact with the opposing player's shoulder causing severe pain. The young man was unable to return to the game due to pain and inability to lift the injured arm. He was taken to urgent care for further evaluation and x-rays. X-rays revealed no clavicle fracture and no shoulder dislocation. He was diagnosed with a shoulder sprain, placed in a sling, and asked to follow up in sports medicine clinic.
On physical exam at the follow-up appointment, the athlete is well appearing and well developed. He is favoring his left shoulder with a slightly slouched position to the left. He has very limited active ROM but is able to forward flex and abduct to 45 degrees. He has no tenderness to palpation over the AC joint but is exquisitely tender over the medial 1/3 of the clavicle with subtle swelling noted.
Repeat x-ray was obtained in clinic which suggested the diagnosis.
A follow-up CT scan was obtained which confirms the diagnosis
What are the key clinical features of this injury?
In my experience, a sternoclavicular joint dislocation can occur in both high velocity and low-velocity injuries such as a simple fall. I have found that these injuries tend to be extremely painful and may appear like the pain is out of proportion to the injury. On exam, many times the athlete just will not allow you to touch the area at all, which is out of the ordinary for most other shoulder injuries. Lastly, the patient may have neck tightness, difficulty swallowing, or even difficulty breathing if the dislocation is posterior. If these symptoms are present, I would consider this an urgent or emergent situation.
What is the major concern when the dislocation is posterior?
The main concern with posterior sternoclavicular joint dislocations is compression or damage to the structures behind the site of injury. Specifically, direct compression or traumatic injury of the trachea, esophagus or vascular structures in the neck. The athlete may present with shortness of breath, difficulty swallowing, numbness or tingling in the extremity. If a patient exhibits any of these symptoms subsequent to the injury, they should be evaluated right away. (ie if you are traveling a substantial distance for a competition, I would have a suspected sc joint dislocation evaluated prior to return)
When should I consider a CT scan to confirm the diagnosis?
Generally speaking, I would always obtain a CT scan on all patients with a suspected posterior sternoclavicular joint dislocation. In particular, I would request a CT angiogram to specifically look at the integrity of the vascular structures in the neck. Additionally, due to the fact that the medial clavicle growth plate can be open up to 25 years of age, I still will usually obtain a CT scan with all anterior dislocations as well. The main issue is that a dislocation can easily be confused with a fracture through the growth plate which may require different treatment.
What is the typical treatment course for a sternoclavicular joint injury?
If the diagnosis is considered a sprain or uncomplicated anterior dislocation usually the patient is treated with a sling for 4-6 weeks similar to the treatment of an acromioclavicular injury. When a posterior dislocation is discovered it can be a medical emergency and usually the treatment is to undergo surgery to place the clavicle back into the joint with appropriate alignment.
SC joint dislocations can occur with low-velocity injuries such as shoulder to shoulder contact or a ground-level fall.
Although clavicle fractures are much more common, an athlete who will not let you touch or examine their sternoclavicular joint should be suspected of a dislocation.
X-rays of the clavicle can be inadequate at assessing the position of the bones at the sternoclavicular joint. A serendipity view x-ray at 40 degrees tilt can be useful but still miss the diagnosis.
A patient with a posterior sternoclavicular joint dislocation should be urgently evaluated with a CT angiogram, especially with symptoms associated with posterior compression.