Bilateral trampoline fracture of the proximal tibia in children
Brief clinical details
A 6-year-old Caucasian girl without medical history was referred to the emergency department because of acute bilateral knee pain and refusal to bear weight on both her legs. The girl came directly from an indoor playground where she had been jumping on a commercial trampoline together with another child. No fall or direct trauma had occurred. Physical examination showed an asthenic habitus, some small bruises on the ventral side of the knees, and pressure pain over both proximal tibiae.
Description of the relevant abnormalities
Anteroposterior and lateral radiographs showed bilateral horizontal, linear, minimally displaced fractures of the metaphysis of the proximal tibia, with buckling of the upper anterior tibial cortex and a cortical breach at the upper posterior tibia, i.e. bilateral trampoline fractures. Bilateral fractures of the proximal tibiae are rare in children and tend to occur mostly in overweight male adolescents or male adolescents during growth spurt. The differential diagnosis include non-accidental injury or fractures due to direct trauma.
Why this image is clinically or educationally relevant?
Bilateral trampoline fractures have never been described and are imported to consider when having non-accidental trauma in the differential diagnosis. Trampoline fractures are transversely oriented impaction fractures of the proximal tibia in young children. They can occur when children jump on a trampoline with another, often heavier, person. The upward bending of the trampoline after a jump of this heavier person exerts increased axial force on the child’s soft, immature tibia when concomitantly landing with the knee in (hyper)extension.
