Rib fractures occur commonly as a result of blunt trauma, and have been documented in up to two thirds of thoracic injury cases.²,³ In one center’s experience, rib fractures were radiographically present in 10% of total trauma admissions.⁴ Isolated or multiple rib fractures are among the most common injuries in the elderly, with an incidence of approximately 12%.⁵ The true incidence of rib fractures, however, is likely underreported, given that up to 50% of rib fractures are not visualized on initial plain x-ray.⁶

Although rib fractures tend to be uncomplicated skeletal injuries requiring no specific orthopaedic treatment, they are associated with significant pulmonary morbidity. Rib fractures are a marker for serious injury, with an 84% to 94% incidence of associated injury including hemothorax, pneumothorax, and pulmonary contusion.³,⁴ Fractures of the lower ribs are associated with abdominal injury, with lower right-sided fractures having a 19% to 56% risk of liver injury, and lower left-sided fractures having a 22% to 28% risk of spleen injury.⁷,⁸ Although often disseminated, there is actually no demonstrated association between first and second rib fractures and blunt aortic injury.⁷,⁹ Overall, rib fractures portend a 12% mortality risk and 33% incidence of pulmonary complications.⁴

Advancing age has been considered to be a significant comorbidity in the setting of rib fractures. Bergeron et al., in a prospectively studied group of 405 patients with rib fractures, demonstrated a five times greater risk of mortality in patients older than 65 years.¹⁰ Bulger et al. also demonstrated an increased mortality rate among patients older than 65 years (22% vs. 10%), as well as an associated increase in the incidence of pneumonia (31% vs. 17%).¹¹ Also, they demonstrated that mortality and pneumonia risk correlated with the number of rib fractures. Each additional fracture was associated with an approximately 20% increase in mortality and pneumonia.

Children, on the other hand, have a much lower incidence of rib fracture given the relative compliance of the pediatric skeleton. The presence of rib fracture suggests a high-energy mechanism. Rib fractures in an infant or toddler in the absence of such mechanism should warrant an investigation into abuse. In children younger than 3 years, rib fracture has been demonstrated to have a positive predictive value of 95% for determining nonaccidental trauma.¹²

Rib fracture generally results from compression on the thoracic cage. Fractures often occur at a 60 degree rotation from the sternum because this area is one of mechanical weakness relative to other locations.¹³ Rib fractures are often segmental, with one break at 60 degrees and the other posterior.¹⁴ A flail segment is created by the segmental fracture of two or more contiguous ribs. The phenomenon of flail chest is discussed in the subsequent text.

It is unusual for rib fractures to require treatment directed at the fractures themselves, such as operative stabilization. Rib fractures tend to heal with good result. Therapy is directed toward the prevention of respiratory embarrassment that may occur. Pulmonary morbidity may result from pain interfering with pulmonary toilet,
underlying pulmonary injury such as contusion, or a combination of the two. Initial therapy consists of pain control, chest physiotherapy, and mobilization. Modalities for pain control include systemic therapies such as narcotics and nonsteroidal antiinflammatory drugs (NSAIDs), and regional therapies including local rib blocks, pleural infusion catheters, and epidural analgesia.

Intravenous narcotics have historically been the mainstay of pain therapy for chest wall trauma, and patient-controlled anesthesia (PCA) has emerged as the most efficacious method to deliver narcotics. The advantages of narcotic analgesia, including ease of administration and monitoring, are tempered by inconsistent efficacy and the tendency of narcotics to cause sedation, cough suppression, and respiratory depression, all detrimental to pulmonary toilet.

Epidural analgesia is the most common regional therapy used for chest wall pain management. Narcotics, anesthetics, or a combination of the two are introduced into the spinal epidural space through a catheter inserted at the thoracic or lumbar level. The main advantages of epidural analgesia are its superior efficacy and absence of side effects detrimental to pulmonary toilet. When compared to intravenous narcotic analgesia, epidural analgesia is associated with improved pain perception and improved performance of pulmonary function tests.¹⁵,¹⁶ There is also evidence that the benefit of epidural analgesia may translate into decreased ventilator days, pulmonary complications, and mortality.¹⁷ The prime disadvantage of epidural analgesia is its relative invasiveness, subjecting the patient to the small but serious risks of epidural infection, epidural hematoma, and direct spinal cord trauma. The contraindications to epidural analgesia are numerous, including coagulopathy, infection, altered mental status, and spinal fracture, limiting its applicability in the multi-injured patient. In a recent study, 64% of patient candidates for epidural analgesia had contraindications to epidural placement as a result of associated injuries.¹⁷