Gait asymmetries in children and adolescents with mild leg length discrepancy.

Background: Leg length discrepancy (LLD) is a common orthopedic condition, yet its clinical significance remains debated. While severe LLD is typically managed surgically, the impact of mild LLD (< 2 cm) on gait asymmetry in children is not well understood.

Research question: This study aims to assess the relationship between mild LLD (< 2 cm) and gait asymmetries in children and adolescents and to compare these asymmetries to those observed in typically developing children (TDC).

Methods: Gait data from 475 patients (13.1 ± 2.3 years) were analyzed retrospectively. Kinematic and kinetic data were collected using 3D motion analysis during barefoot level walking. Patients were categorized into four LLD groups (1-4 mm, 5-9 mm, 10-14 mm, 15-20 mm). Differences in gait asymmetries and relationships to LLD magnitude were analyzed using statistical parametric mapping ANOVA and regression. Differences in spatial-temporal parameters were analyzed using one-way ANOVA. Clinical relevance of asymmetries was judged using normal asymmetry ranges of 40 TDC.

Results: Increased LLD was associated with greater pelvic obliquity, hip adduction, and internal hip rotation on the longer leg side, as well as increased hip flexion, knee flexion, ankle dorsiflexion, and delayed heel rise. These gait asymmetries became clinically relevant compared to TDC at LLD ≥ 1 cm. Kinetic asymmetry differences were negligible.

Significance: Mild LLD < 1 cm does not significantly affect gait, while LLD ≥ 1 cm induces clinically relevant asymmetries, particularly in pelvic obliquity. These findings support the use of non-operative interventions, such as shoe lifts, for LLD exceeding 1 cm to mitigate gait asymmetries.