Sonographic detection of radiographically occult fractures in pediatric ankle and wrist injuries.

Background: In some pediatric ankle and wrist injuries, the clinical picture is suggestive of a fracture despite negative standard radiographs. Objective: The goal of this prospective study was to determine the effectiveness of high-resolution ultrasound (US) in differentiating radiographically occult fractures from sprains. Methods: During a period of 3 years children aged 2 to 16 years, who sustained an acute ankle and wrist injury suggestive of being a fracture on clinical examination, but with negative radiograph, were referred for high-resolution US. Follow-up radiographs were obtained at 2 to 3 weeks. Results: Fifty-eight children (41 children with ankle injury and 17 children with wrist injury) were examined. In 41 patients, US did not reveal fractures, and in 15, small fractures were detected. All patients with negative US studies had negative follow-up x-rays. In 13 patients with positive US, the follow-up radiographs demonstrated a periosteal reaction. In 2 children (1 in each group) in whom a fracture line identified by US was in the depth of the metaphyseal bone, the follow-up radiogram demonstrated an area of increased bone density. In 2 children, 1 in each group, US diagnosed fractures that were not confirmed by follow-up radiograms. Conclusion: Ultrasound is effective in the detecting radiographically silent fractures of the pediatric ankle and wrist. Ultrasound may be used as an adjunct to radiography in clinically suspicious but radiographically negative ankle and wrist injuries. Level of evidence: 1.