Prevalence and Risk Factor Analysis of Leg Length Discrepancy in Patients with a Capillary Malformation on the Lower Extremities: A Retrospective Cohort Study

Objective: The study aimed to determine the prevalence of major leg length discrepancy (LLD ≥2 cm) among patients with lower-limb capillary malformation (CM) and to identify the risk factors that influence LLD development. Methods: This retrospective cohort study included patients with lower-limb CM, such as regional CM (RCM), capillary venous malformation (CVM), diffuse CM (DCM), and CM-arteriovenous malformation. LLD was evaluated using physical and radiographic methods. Detailed descriptive analysis was performed. Regression analysis was used to investigate risk factors, while Kaplan–Meier analysis estimated the progressive risk of developing LLD by age 15. Results: We included 1,008 patients with a lower-limb CM, categorized as regional CM (n=710, 70.4%), capillary venous malformation (n=121, 12.0%), DCM (n=128, 12.7%), and CM-arteriovenous malformation (n=49, 4.9%). Major LLD developed in 14.8% of cases, with the highest incidence observed among patients with DCM (44.5%). Kaplan–Meier analysis estimated a 31.4% overall progressive risk of developing major LLD by age 15, rising to 66.4% in the DCM group. Significant LLD predictors included DCM subtype, proximal CM location (odds ratio [OR], 1.40; 95% confidence interval [CI], 1.09–1.83; P = .01), full-length leg involvement (OR: 7.00, 95% CI: 4.83–10.02, P < .001) and combined medial and lateral side involvement (OR: 6.73, 95% CI: 3.69–12.4, P < .001). Conclusion: Major LLD is common in children with lower extremity CM, particularly in those with DCM. Significant predictors of major LLD include larger affected areas, proximal location, full-length leg extent, and combined medial and lateral position. Early and accurate identification of these risk factors is crucial for timely surgical intervention.