Sternal fracture

Sternal fractures occur in ~5% of blunt chest trauma with the manubrium being the most commonly injured part.

Clinical presentation

Acute, severe sternal pain that is worse with respiration with localized tenderness.

Pathology

Mechanism of injury

Fractures of the sternum can result from both direct and indirect blunt force trauma to the chest with motor vehicle accidents the most common cause ^1,3:

• direct: impact on a steering wheel; falls; contact sports; pedestrian vs. car accidents; assaults
• indirect: deceleration injuries from motor vehicle accidents; stress fractures; osteoporotic fractures
• non-accidental injuries in children

Associations

Associated injuries are common, occurring in ~50% (range 33-67%) of patients ^1,3:

• rib fractures, sternoclavicular joint dislocation
• mediastinal hemorrhage, pneumothorax, hemothorax, cardiac tamponade, cardiac contusion, pulmonary contusion
• thoracic spine compression fracture
• traumatic brain injury

Radiographic features

Plain radiograph

Sternal fractures are best detected on dedicated lateral sternal views as lucent cortical breaches with or without displacement. Undisplaced fractures are poorly visualized on plain x-rays.

US

• can also be used to assess for sternal fractures
• as with plain X-ray, US can show a cortical fracture or step
• just as accurate as lateral radiographs but less reliable in determining displacement ⁵

CT

• modality of choice; sagittal reformats most sensitive
• can assess for anterior cortical breach and posterior cortical breach, with the latter being associated with more severe neurovascular injuries ³

Treatment and prognosis

Isolated sternal injuries have a very good outcome with conservative management with most healing in a few months with a very low mortality rate (<1%) ¹. However, sternal fractures associated with other injuries have a higher mortality rate.

Differential diagnosis

• sternal foramen: developmental anomaly found in ~5% of the population