sternoclavicular joint dislocation

Sternoclavicular joint (SCJ) dislocation is rare, accounting for only ~2% of joint dislocations and especially when compared to other traumatic upper limb injuries such as clavicular fractures.

Epidemiology

Most cases result from indirect trauma , especially high-speed motor vehicle accidents. Spontaneous dislocations can also occur, these are typically anterior and occur in young men .

Associations

Sternoclavicular joint dislocations are associated with the following injuries :

Clinical presentation

Anterior dislocation causes a palpable deformity. Posterior dislocations may be occult on physical examination but, due to compression of thoracic structures, present with dyspnea, stridor, or dysphagia.

Pathology

The injury can be broadly categorized into two types:

  • anterior
    • two-to-three times more common
    • less serious
  • posterior
    • often occult clinically
    • can be occult or subtle on radiographs
    • potentially more serious because of the possibility of damage to mediastinal structures (e.g. great vessels, trachea, esophagus, etc.) as a result of posterior displacement of the medial clavicle head
    • these injuries should prompt assessment of the mediastinal structures with CTA

Bilateral dislocations are easily missed on plain film imaging, a rare however necessary consideration, best demonstrated on cross-sectional imaging .

Radiographic features

Plain radiograph
  • joint space widening at the sternoclavicular joint
  • more easily visualized on an angled view, on this view inferior displacement of the medial head of the clavicle is indicative of a posterior dislocation, whereas superior displacement of the clavicle indicates an anterior dislocation
  • difficult to determine anterior or posterior dislocation 
CT

Treatment and prognosis

Options include conservative treatment, especially for anterior dislocation. Posterior dislocations are normally treated with closed reduction. Surgical fixation (ORIF) is usually reserved for unreduced posterior dislocations .

Thoracic outlet syndrome may occur as a late complication of posterior dislocation.