Wire bending development and progression during Ilizarov system tibial lengthening in skeletally immature patients with achondroplasia

Tensile strength develops on wires during distraction osteogenesis (DO) using the Ilizarov system. The increase of tensile strength can lead to bending of the wires. The purpose of this study was to investigate the development and progression of wire bending during tibial lengthening using the Ilizarov system. We also identified factors that contribute to wire bending. Seventy-two segments of 36 skeletally immature achondroplasia patients (mean age, 8.5 years; range, 5.1–14.4 years) with bilateral tibial lengthening with the Ilizarov system were included in this study. The wire bending was defined as cases with loss of linearity of the wire during DO. The average distance of proximal and distal wires to the adjacent ring throughout the entire DO was measured to determine the progression of wire bending. In addition, age, height, weight, initial tibial length, gain of length, amount of correction of angular deformity, distraction index, external fixation index, and healing index were investigated to identify potential contributors to wire bending. Wire-related complications, including wire breakage, were also assessed. Wire bending increased in the distraction phase (p ​