Treatment Efficiency Following Pediatric Tibial Lengthening Using Monolateral External Fixation: The Role of Surgical Planning and Postoperative Complications

Abstract

Background: Pediatric tibial lengthening requires prolonged treatment and may be complicated by adverse events that affect both achievement of the planned correction and biological treatment efficiency. Evidence regarding these complementary dimensions in children treated with monolateral external fixation remains limited. Methods: We conducted a retrospective cohort study of pediatric patients who underwent tibial lengthening with a monolateral external fixator between June 2018 and June 2023 at a tertiary pediatric orthopedic center. Planned and achieved lengthening, treatment duration, distraction, maturation, and healing indices, and postoperative complications were evaluated. Complications were analyzed according to overall occurrence, cumulative burden, and pin-site severity. Associations were explored using nonparametric comparisons, Spearman correlations, logistic regression, and robust linear regression. Results: Thirty-nine patients were included; the median age was 14 years (interquartile range [IQR], 11–16), and 69.2% were male. Median distraction, maturation, and healing indices were 0.60 mm/day (IQR, 0.46–0.78), 4.48 days/mm (IQR, 3.03–6.50), and 6.29 days/mm (IQR, 4.90–9.00), respectively. Patients who failed to achieve the planned correction had greater planned lengthening targets. After adjustment for overall complication status, each additional millimeter of planned lengthening was associated with approximately 7% higher odds of failure to achieve the planned goal (odds ratio, 1.07; 95% confidence interval, 1.01–1.16; p = 0.046). Postoperative complications were associated with longer distraction and healing periods and higher healing indices. In robust models adjusted for achieved lengthening, any complication was associated with an approximately 41% higher healing index (p = 0.010), while each increase in pin-site severity was associated with an approximately 22% higher healing index (p = 0.009). Increasing complication burden showed a progressive pattern of prolonged healing. Conclusions: Pediatric tibial lengthening outcomes may be understood through two complementary dimensions. Greater planned lengthening was associated with a lower probability of fully achieving the intended correction, whereas postoperative complications primarily affected treatment efficiency and duration. Careful planning and early complication control may therefore represent complementary strategies for reducing treatment burden.