Radiographic imaging for Ilizarov limb lengthening in children.

The Ilizarov method for limb lengthening is rapidly gaining popularity in North America. Use of this new technique has necessitated modifications in radiographic protocol. Initial imaging problems gained from our experience with twenty children are detailed including accurate centering for the plain films, correcting for magnification to accurately measure the distraction gap and the expected radiographic appearance of the regenerate bone. Ultrasonography has potential value in accurately measuring the distraction gap and in imaging the new bone prior to radiographic appearance. Since overly fast distraction inhibits bone formation and overly slow distraction leads to premature consolidation, ultrasound may serve a useful role in the qualitative evaluation of new bone formation in Ilizarov limb lengthening, enabling the orthopedic surgeon to tailor the distraction rate to the particular child.