THE CASE
A 14-year-old boy sought care at our clinic for persistent chest pain after being hit in the chest with a teammate’s shoulder during a basketball game 3 weeks earlier. He had aching midsternal chest pain that worsened with direct pressure and when he sneezed, twisted, or bent forward. There was no bruising or swelling.
On examination, the patient demonstrated normal perfusion and normal work of breathing. He had focal tenderness with palpation at the manubrium with no noticeable step-off, and mild tenderness at the adjacent costochondral junctions and over his pectoral muscles. His sternal pain along the proximal sternum was reproducible with a weighted wall push-up. Although the patient maintained full range of motion in his upper extremities, he did have sternal pain with flexion, abduction, and external rotation of the bilateral upper extremities against resistance. Anteroposterior (AP) and lateral chest radiographs were unremarkable.
THE DIAGNOSIS
The unremarkable chest radiographs prompted further investigation with a diagnostic ultrasound, which revealed a small cortical defect with overlying anechoic fluid collection in the area of focal tenderness. T2-weighted magnetic resonance imaging (MRI) of the chest was performed; it revealed a transverse, nondisplaced fracture of the superior body of the sternum with surrounding bone marrow edema (FIGURE).
DISCUSSION
Fractures of the sternum comprise < 1% of traumatic fractures and have a low mortality rate (0.7%).1,2 The rarity of these fractures is attributed to the ribs’ elastic recoil, which protects the chest wall from anterior forces.1,3 These fractures are even more unusual in children due to the increased elasticity of their chest walls.4-6 Thus, it takes a significant amount of force for a child’s sternum to fracture.
While isolated sternum fractures can occur, two-thirds of sternum fractures are nonisolated and are associated with injuries to surrounding structures (including the heart, lungs, and vasculature) or fractures of the ribs and spine.2,3 Most often, these injuries are caused by significant blunt trauma to the anterior chest, rapid deceleration, or flexion-compression injury.2,3 They are typically transverse and localized, with 70% of fractures occurring in the mid-body and 17.6% at the manubriosternal joint.1,3,6
Athletes with a sternal fracture typically present as our patient did, with a history of blunt force trauma to the chest and with pain and tenderness over the anterior midline of the chest that increases with respiration or movement.1 A physical examination that includes chest palpation and auscultation of the heart and lungs must be performed to rule out damage to intrathoracic structures and assess the patient’s cardiac and pulmonary stability. An electrocardiogram should be performed to confirm that there are no cardiovascular complications.3,4
Initial imaging should include AP and lateral chest radiographs because any displacement will occur in the sagittal plane.1,2,4-6 If the radiograph shows no clear pathology, follow up with computed tomography, ultrasound, MRI, or technetium bone scans to gain additional information.1 Diagnosis of sternal fractures is especially difficult in children due to the presence of ossification centers for bone growth, which may be misinterpreted as a sternal fracture in the absence of a proper understanding of sternal development.5,6 On ultrasound, sternal fractures appear as a sharp step-off in the cortex, whereas in the absence of fracture, there is no cortical step-off and the cartilaginous plate between ossification centers appears in line with the cortex.7
Continue to: A self-limiting injury that requires proper pain control