Keywords: x-ray, child abuse, fracture dating (PubMed Search)
Imaging plays an important role in the evaluation of child abuse.
It aids in the identification, evaluation and in treatment.
Additionally, it is often the only objective evidence of abuse available to the courts.
It is often discovered through two means.
1) Injuries/fractures that are inconsistent with the alleged mechanism of injury.
2) Pathognomonic fracture patterns are found on routine radiographs
The ED physician should not attempt to precisely "date" the injury.
That said, soft tissue swelling resolves in 2-5 days. The periosteum becomes radiodense in 7 to 10 days. In subtle fractures this may be the only radiographic finding. If there is no evidence of bone healing (periosteal reaction), the fracture is less than 2 weeks old. Callus formation and resorption of the bone along the fracture line begins at 10 to 14 days. The callus is visible for up to 3 months. Bone remodeling continues for up to one year.
Emergency Radiology, chapter 22, "pediatric considerations" by Ken Butler and Martin Pusic.