Teaching Case

A 33-year-old man presented to ER following a skiing accident, reporting a trauma to lower cervical spine. Clinical examination revealed tenderness in the anterior chest. The past medical history was unremarkable.

An anteroposterior radiograph of the chest was performed (Fig. 1), showing no alterations. The lateral radiograph (Fig. 2), focused on the point of tenderness, revealed a type II manubriosternal joint dislocation.

Traumatic manubriosternal joint dislocation is a rare and potentially serious injury; it can be associated with concurrent injuries to ribs, lungs, or myocardium [1]. We can distinguish two kind of manubriosternal dislocation, depending on the position of the sternum in relation to the manubrium: in type I dislocation, the body of the sternum is displaced in a dorsal direction; in type II dislocation, the sternal body is displaced on the ventral side of the manubrium. Direct or indirect traumatic events may cause manubriosternal dislocation: direct injuries generally result from a road accident collision, and they may evolve in either a type I or a type II dislocation; an indirect trauma always leads to a type II dislocation, due to a spine flexion-compression mechanism. An isolated manubriosternal dislocation is unusual because the flexion-compression mechanism is usually associated with vertebral fractures [2].
A plain radiograph centred on the sternum in lateral view is fundamental to achieve a diagnosis [3]. CT can be indicated in exceptional cases, in particular when the patient showed signs of thoracic compression.
Treatment of this condition is problematic: non-operative management after reduction is associated with a considerable rate of subluxations or reluxations, especially due to weak patient compliance. Moreover these disorders can lead to chronic pain, periarticular calcification with ankylosis, and progressive deformity [4]. Whenever the dislocation is associated with instability, pain or respiratory distress, the surgical fixation should be considered.