Rib fractures are a common consequence of trauma and can cause life-threatening complications.
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Epidemiology
Associations
Rib fractures are often associated with other injuries and the greater the number of rib fractures the more likely are associated injuries 1,3:
brachial plexus or subclavian vessel injuries (1st-3rd rib fractures
liver, kidney and spleen traumatic injuries (10th-12th rib fractures)
Pathology
The 4th-10th ribs are the most commonly fractured 1. Fractures of the 1st-3rd ribs are associated with high-energy trauma 3.
When the rib is fractured twice, the term floating rib is used to describe the free fracture fragment, and when three or more contiguous floating ribs are present this is called a flail chest.
Buckle rib fractures can also occur, one of the rare instances of buckle fractures in a mature skeleton.
Etiology
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blunt and penetrating trauma: e.g. motor vehicle accidents, falls, assaults
most common injury in blunt thoracic trauma, occurring in 50% of cases 3
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occur more commonly in high-level athletes
occur laterally and anterolaterally
repetitive overhead movements (e.g. weight lifting, basketball) can result in 1st rib stress fractures
twisting movements (e.g. rowing, swimming) can result in middle and lower rib stress fractures
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decreased bone density increases risk of rib fractures 22,23
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non-accidental injuries in children
typically posterior fractures
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typically posterior 20
cardiopulmonary resuscitation (CPR): rib fracture occurs in 1 in 3 5
fetal rib fractures: caused by skeletal dysplasias
spontaneous: spontaneous rib fracture
Radiographic features
Plain radiograph
may miss up to 50% of rib fractures even with dedicated oblique rib projections 1
Ultrasound
A common application of point of care ultrasonography, used in a complementary manner to conventional radiography in the workup of blunt chest wall trauma and localized chest pain. Ultrasonography is more sensitive and specific than conventional radiography for rib fracture detection in blunt trauma when performed by a trained clinician 12,14.
Moreover, the use of sonography allows the detection of radiographically occult costal cartilage fractures, as well as assessment of the underlying lung for associated traumatic pathology, including;
B-mode
the cardinal sonographic feature is a discontinuity of the otherwise smooth, linear echogenicity corresponding to the anterior bony cortex
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if accompanied by cortical displacement, may be further characterized by the axial distance between the cortical margins 14
separation by less than 1 mm defines mild displacement
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considered severe when >4 mm
often associated with comet tail artifacts extending from the fracture site into the far-field
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if initially occult, obvious interruption of the bony cortex may be elicited with sonopalpation (applying local transducer pressure)
appropriate analgesia may be necessary before attempting this maneuver
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suggestive findings include a circumscribed, hypoechoic fluid collection adjacent to the putative fracture site
represents a fracture hematoma, fluid nature may be ascertained through careful adjustment of gain settings and dynamic variation of the observed shape with pressure
associated periosteal elevation appears as a delicate, raised hyperechoic linear stripe
CT
more sensitive than plain radiography for the detection of rib fractures 1,3
displacement on CT may be defined as greater than half a rib shaft width 19
Nuclear medicine
Tc-99m bone scan is sensitive but not specific for rib fractures and demonstrates focal areas of high-uptake, which need to be correlated with SPECT or radiographic imaging 1,7
Treatment and prognosis
Rib fractures themselves are treated symptomatically and have a good prognostic outcome. Rarely, severe rib injuries (e.g. flail chest) may be treated with ORIF (surgical stabilization of rib fracture, SSRF) often in the setting of other severe traumatic injuries and in the hope that respiratory function will improve facilitating a shorter ICU stay and quicker recovery.
Complications
Aside from immediate traumatic complications outlined above atelectasis and pneumonia may develop, mainly due to poor respiratory effort secondary to pain, and this increases the morbidity and mortality due to rib fractures 3.