Correction of Complex Lower Limb Angular Deformities with or Without Length Discrepancy in Children Using the TL-HEX Hexapod System: Comparison of Clinical and Radiographical Results

The aim of this study was to compare clinical and radiographical results for treatment of lower limb multiaxial deformities±limb length discrepancy (LLD) of at least 2 cm with the Truelok hexapod fixator system (TL-HEX). All consecutive cases of lower limb multiaxial deformities were included. Patients were divided in two groups: group 1, lower limb angular deformity+LLD less than 2 cm, and group 2, lower limb angular deformity+LLD of at least 2 cm. Only patients with age younger than or equal to 20 years and follow-up of 6 months after removal of the external fixator were included. A total of 27 (six femur and 39 tibia treated) and 20 patients (12 femur and 19 tibia) were enrolled in groups 1 and 2, respectively. Complete correction of the deformity was achieved in 90 and 96% of the patients in groups 1 and 2, respectively. There were no differences in terms of external fixator, maturation, and distraction indexes between the two groups and between different anatomical sites. Good to excellent functional results (ASAMI score) were obtained in 93% of patients in group 1 and 75% in group 2 (P=0.01). Complication rate was similar between the two groups (7.4 vs. 10%, respectively). Average follow-up after removal of the external fixator was 25.6 (range: 7.0-54.0) months. The TL-HEX external fixator system allows a predictable correction of complex lower limb deformities regardless of the presence of LLD. Although complication rate is similar between the two groups, lower functional outcomes can be expected in patients with significant preoperative LLD.