New bone formation accelerates during lower limb lengthening and deformity correction in children with Ollier’s disease

BACKGROUND: Ollier’s disease can cause severe length discrepancy of the lower extremities and deformity in children. Osteotomy and limb lengthening with external fixation can correct the limb deformity. This study evaluated (1) whether the duration of external fixation was reduced in patients with Ollier’s disease, and (2) the incidence of complications such as pin tract infection, external fixation loosening, and joint stiffness. METHODS: Two groups were compared with respect to age, angular correction (AC), lengthening gap (LG), distraction index (DI), lengthening length (LL), lengthening length percentage (L%), lengthening index (LI), bone healing index (BHI), and external fixation index (EFI). Group 1 (Ollier’s disease) comprised nine patients undergoing 11 lower limb lengthening procedures using external fixators; group 2 (control, normal lengthened bone) comprised 28 patients undergoing 29 lengthening procedures with external fixators. RESULTS: In patients with Ollier’s disease, full correction of the deformity and full restoration of length were achieved in all cases. In the femur, the mean AC (15.97° vs. 6.72°) and DI (1.11 mm/day vs. 0.78 mm/day) were significantly larger, while the LI (9.71 days/cm vs. 13.49 days/cm), BHI (27.00 days/cm vs. 42.09 days/cm), and EFI (37.86 days/cm vs. 56.97 days/cm) were all significantly shorter in group 1 than in group 2 (p < 0.05). In the tibia, the mean AC and L% were larger, while the LG, LI, BHI, and EFI were all shorter in group 1 than in group 2. There was no significant difference between the two groups in the incidence of complications. CONCLUSION: In children with Ollier’s disease, new bone formation accelerated and the healing speed of the lengthened segments was faster throughout the whole lengthening period with external fixation, and full correction of the deformity and full restoration of length could be achieved. Level of Evidence III