Radiographic features of limb lengthening in children.

We report our experience in radiographic imaging in limb lengthening procedures using callotasis for limb lengthening discrepancy with the Orthofix dynamic monoaxial external fixator. Seventeen patients (average age at operation 10.8 years) completed 22 bone segments (7 femora, 11 tibiae, 4 ulnae) lengthening procedures. The average time for formation of good medullary bridging was over 6 months. The commonest radiographic abnormality was a periosteal reaction around the pin sites seen in 14 patients, while evidence of pin loosening was present in 10. All patients with pin loosening also showed periosteal reaction which pre-dated the loosening in 5 of 12 patients by an average of 47 days. Angulation was detected in 9 patients in the a.p. plane, and in 6 in the lateral plane. Six patients developed a ragged radiolucent region through the newly forming bone at an average of 95 days from the corticotomy but with uneventful healing.