Early MR imaging of lower-extremity physeal fracture-separations: a preliminary report.

Magnetic resonance imaging (MRI) was used to evaluate physeal fracture-separations in children soon after at-risk lower-extremity fractures. MRI scans taken during the "acute" period (within 10 days of fracture) resulted in a change in three of four of the Salter-Harris classifications from the injury radiographs. Twelve children had MRI scans performed in the "early" period (3-17 weeks following fracture). Physeal narrowing or tethering and the absence of Harris arrest lines were found in those patients who subsequently required late surgical intervention. Acute MRI provides the most accurate evaluation of the physeal fracture anatomy. Early MRI can demonstrate transphyseal bridging or altered arrest lines in physeal fracture before they become manifest on radiographs.