Multi-modality imaging characteristics of costochondral fractures, a highly specific rib fracture for child abuse

Abstract

Background: Rib fractures in young children are strongly associated with nonaccidental trauma (NAT). Costochondral junction (CCJ) fractures are unique with most being identified in the healing phase on radiographs. NAT-associated CCJ fractures, therefore, may be underdiagnosed. Improved diagnoses of CCJ fractures may lead to better identification of NAT.

Objective: To document the association of CCJ fractures with NAT, and improve CCJ fracture recognition by documenting the imaging features with multiple radiologic modalities.

Materials and methods: Children, ages 0-4 years, with CCJ fractures on radiologic reports were identified over a 10-year period. All available radiographic skeletal surveys, chest radiographs, computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound (US) studies were reviewed. We chose CT as the radiologic gold standard. Imaging patterns of the primary fracture and healing changes were documented. The diagnosis of NAT by the child protective team was documented.

Results: One hundred and nine CCJ fractures were found in 22 patients, 21 of whom were diagnosed with NAT (95.5%). Radiographic skeletal survey identified 34.6% of CCJ fractures (P < 0.0001) with a sensitivity of 32.5% and specificity of 99.2%. MRI identified 50.0% of CCJ fractures with a sensitivity of 42.9% and specificity of 98.1%.

Conclusion: CCJ fractures are highly specific for NAT. As sensitivity is low for radiographic skeletal survey in CCJ fracture diagnosis compared with CT, CT may have a role in confirming a clinical suspicion of NAT.

Keywords: Child abuse; Computed tomography; Costochondral junction; Fracture; Infants; Magnetic resonance imaging; Nonaccidental trauma; Radiography; Rib.