[Objective] The purpose of this study was to evaluate whether patients with length unstable tibia fractures had a higher complication rate thanthose with length stable fractures when treated with ESIN.[Methods] All patients with diaphyseal tibia fractures treated with ESIN from January 2016 to December 2021 at a single institution were reviewed. [Results] A total of 90 patients with 90 diaphyseal tibia fractures treated with EINs were included in the study. In all, 62.3% of the fractures were categorized as length stable and 37.7%were length unstable. Three length stable patients had a residual angular deformity compared with one length unstable patient (P=1.000). The length unstablegroup experienced more shortening at the fracture site than the patients in the length stable group (P=0.000), but no patient required further intervention for their shortening. No relationship was observed between fracture pattern and frequency of complications (length stable 8.9% vs. length unstable 11.8%, P=0.725).[Conclusions] There was no significant difference in complication rate between length stable and unstable fractures treated with ESIN. While fracture shortening was more likely in the length unstable group, it did not result in increased rate of limb length discrepancy at final follow-up.Elastic intramedullary nailing is an ideal choice for the treatment of unstable tibial fractures in children.