Frequency of intrathoracic injuries in children younger than 3 years with rib fractures.

BACKGROUND: Research documents that among children admitted to trauma intensive care units the number of rib fractures sustained indicates the child's likelihood of having and severity of intrathoracic injury. This has been misused in court to argue that children with multiple rib fractures who lack intrathoracic injury have abnormal bone fragility rather than inflicted injury.

OBJECTIVE: To determine frequency of intrathoracic injuries in children younger than 3 years with rib fractures in cases of child abuse and accidental trauma.

MATERIALS AND METHODS: We conducted a retrospective review of rib fractures caused by documented abuse or accidents from 2003 to 2010 in children treated at Seattle Children's Hospital and Harborview Medical Center. A senior pediatric radiologist and radiology fellow independently reviewed the imaging. Children with bone demineralization were excluded. Descriptive and simple comparative statistics were used.

RESULTS: Seventy-two percent (47/65) of infants and toddlers with rib fractures were abused. Abused children had more rib fractures than accidentally injured children (5.55 vs. 3.11, P = 0.012). However intrathoracic injuries as a whole (55.6% vs. 12.8%, P < 0.001) and individual types of intrathoracic injuries were more common with accidents. Rates of other thoracic cage injuries did not differ substantially (27.8% accidents vs. 12.8% abuse, P = 0.064). Intracranial and intra-abdominal injuries and skull fractures were equally frequent, but other extrathoracic fractures were more common with abuse (70.2% vs. 16.7%, P < 0.001).

CONCLUSIONS: Abused infants and toddlers have fewer intrathoracic injuries but more rib fractures than accidentally injured peers. This likely reflects different injury mechanics. Lack of intrathoracic injuries in abused children with rib fractures does not imply bone fragility.