Impact of mild leg length discrepancy on pelvic alignment and gait compensation in children.

BACKGROUND

Leg length discrepancy (LLD) is common in children and often leads to pelvic lateral tilt as a primary gait deviation. While children rarely report low back pain, prolonged LLD can induce lasting changes in lumbar spine biomechanics, potentially resulting in future back issues. To mitigate the effects of LLD, children often employ various compensatory mechanisms. However, the degree of LLD that significantly impacts gait remains unclear.

RESEARCH QUESTION: This study aims to identify gait deviations in children and adolescents with mild LLD and examine the relationship between LLD severity and lower limb compensatory strategies.

METHODS

Fifty-one children and adolescents (mean age 12.6 years, SD = 2.5) with mild LLD ranging from 0.0 to 3.0 cm were enrolled. Exclusion criteria included neurological involvement, scoliosis, syndromes, and lower extremity joint contractures. Pelvic motion and gait compensations were evaluated across three groups: LLD 0-1 cm, LLD 1-2 cm, LLD 2-3 cm Correlations between gait parameters and LLD were assessed.

RESULTS

Pelvic lateral tilt showed significant correlations with LLD severity. Kinematic analyses revealed significant joint adaptations on the long leg side, leading to functional shortening, particularly in the 2-3 cm group, which displayed multiple and clear compensations. Notably, only ankle dorsiflexion on the long side significantly correlated with LLD.

SIGNIFICANCE: In cases of mild LLD, pelvic adaptations include lateral tilt, counterbalanced by lowering the longer leg. In absence of ankle contractures, individuals tend to avoid lengthening the shorter leg through toe walking, as it requires greater muscular effort. These adaptive strategies correlate with LLD severity, suggesting that even mild discrepancies may contribute to overuse injuries affecting the spine and longer limb. This study highlights the importance of recognizing and addressing mild LLD in relation to symptoms associated with pelvic tilt and ankle issues on the long leg.