Sternal Fracture

Updated: May 25, 2016
  • Author: Scott Felten, MD, FACEP; Chief Editor: Trevor John Mills, MD, MPH  more...
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Overview

Background

Sternal fractures are predominantly associated with deceleration injuries and blunt anterior chest trauma (incidence of 3-6.8% in motor vehicle collisions). Lateral chest radiograph is considered the gold standard for making the diagnosis, because fracture and displacement or dislocation occurs in the sagittal plane. An anteroposterior chest radiograph can be helpful in detecting other injuries, such as rib fracture, pulmonary contusion, hemothorax, and pneumothorax. Mortality associated with sternal fracture is 0.7%. [1]

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Pathophysiology

Most sternal fractures are caused by blunt anterior chest trauma, although stress fractures have been noted in golfers, weight lifters, and other participants in noncontact sports. Insufficiency fractures caused by abnormally decreased bone density or weakened bone can occur spontaneously in patients with osteoporosis or osteopenia (particularly in older persons, especially women), those on long-term steroid therapy, or those with severe thoracic kyphosis. Cardiopulmonary resuscitation commonly causes rib and sternal fractures, something that must be considered during the recovery process from the illness that led to the cardiac arrest.

Fractures usually occur at the body or the manubrium. In one study of 79  patients with sternal fracture, 13 (16.5%) had a fracture of the manubrium, 10 caused by seat-belt injury. In 3 cases stabilization was performed, and follow-up showed sufficient consolidation without complications. [2]

Surface anatomy of the sternum is shown in the illustration below.

Posterior surface of the sternum. Posterior surface of the sternum.
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Epidemiology

Motor vehicle collisions account for 60-90% of sternal fractures. [3] Most of these are in older vehicles in which a seat belt is used but no airbag deploys. [4] Those who were unrestrained generally sustained injury from ejection from the vehicle or impact with the steering wheel or dashboard. Direct impact sports, falls, vehicle-to-pedestrian accidents, and assaults account for most of the rest. Spontaneous fractures and stress fractures are rare.

The mortality rate from isolated sternal fracture is extremely low. Death and morbidity are related almost entirely to associated injuries such as aortic disruption, cardiac contusion, and pulmonary contusion, or unrelated injuries to the abdomen or head sustained in the accident.

Sternal fractures are slightly more common in females than in males, possibly because of shoulder restraint positioning; however, the difference is small. Sternal fractures are more common in patients older than 50 years, possibly because of a weaker or inelastic bony thorax. Because of the elasticity of their chest walls, children less commonly have sternal fractures; however, when present, the underlying injuries may be more severe. [5]

Because of the lack of substantial change in size or shape of the sternum between ages 30 and 100 years, the increased incidence of sternal fracture in the elderly may be the result of cortical thickness or bone mineral density changes in the sternum, as opposed to changes in morphology. [5]

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Prognosis

The prognosis is excellent for isolated sternal fractures. Most patients recover completely over a period of several weeks.

In rare cases of nonunion and chronic sternal pain, surgical fixation can be considered.

During pregnancy, shield the abdomen and pelvis with a lead apron prior to obtaining required chest radiographs. NSAIDs for analgesia are contraindicated outside the first trimester, though several category B opiate combinations exist for pain management.

In older people, provide adequate analgesia; however, consider that a patient's baseline level of independent function may be compromised by adequate analgesics. Consider appropriate arrangements for assistance. Consideration for admission is supported by current trauma literature.

Although no evidence specifically links sternal fractures to abuse in this age group, [6] they are unusual injuries in children. Just like long bone fractures and rib fractures, sternal fractures should heighten the suspicion of child abuse. Sternal fractures are also more difficult to recognize on radiographs in the pediatric population and should be suspected if deformity, crepitus and significant pain are present.

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