The case
An infant presents with swelling of the ankle after being picked up from the babysitter. He has been able to pull to stand and cruise for a while now, but appears to be in pain when he attempts to bear weight after he pulls up to stand. X-Rays reveal the following.
Diagnosis
This is a metaphyseal corner fracture. AKA a metaphyseal chip fracture. It is very concerning for non-accidental trauma. It is though to occur when a limb is grabbed or twisted forcefully, perhaps while the child is being shaken, and the corner of the metaphysis shears off. It may present with pain and discomfort – or be seen incidentally on X-Rays obtained in a skeletal series. It is related to the “bucket handle” fracture which is more significant in terms of the degree of shearing. See the sample image below with both a corner and bucket handle fracture.
Corner fracture above, and bucket handle fracture below
Management
This fracture does not require reduction or operative repair in the vast majority of cases unless the displacement is extreme. More importantly, as this fracture can be considered pathognomonic for non-accidental trauma, discovery of a corner fracture should prompt a more thorough workup. In the case above, this would include a skeletal survey, head CT and labs designed to screen for intraabdominal injury (AST, ALT, amylase, lipase, CBC, urinalysis, troponin).
