Evaluating the results of long tubular bone distraction with an advanced rod monolateral external fixator for achondroplasia.

The work aimed to evaluate the effectiveness of the developed distraction system based on the rod external monolateral fixation mechanisms by comparing it with the classical technique of long tubular bones distraction based on the circular multi-axial system. The study included patients with a genetically confirmed diagnosis of achondroplasia. The experimental group consisted of 14 patients who underwent surgical limb lengthening by the rod monolateral external fixator with a distraction system developed by the authors. The lengthening was performed on 28 segments of tubular bones. The majority of the experimental group patients achieved the lengthening value close to the planned one and the deformation correction. The fixation period was averagely 83.8 ± 3.7 days, the regenerate length was 8.5 ± 0.6 cm, and the mechanical strength of the distraction regenerate was 10.3° ± 2.18°. The rod external fixator with a control distraction system developed by the authors has small dimensions and low weight of the external supporting elements of high durability. It is reported to provide a good psychological tolerance of the treatment process and significantly outperforms the circular multi-axis system. Considering the aforementioned, the proposed apparatus can grant good orthopedic care to patients with achondroplasia.