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The Significance of Lower Limb Asymmetry in the Assessment of Spinal Deformities in Individuals with Scoliotic Posture and Scoliosis

Year: 2026

Type: article

Abstract: Background: Adolescent Idiopathic Scoliosis (AIS) and scoliotic posture present complex three-dimensional interactions between pelvic obliquity and spinal alignment. Leg length discrepancy (LLD) is frequently observed in individuals presenting with scoliotic posture and is associated with pelvic obliquity and compensatory posture. This study evaluated the relationship between lower limb asymmetry and spinal curvature, incorporating age-restricted and curve-severity sensitivity analyses. Methods: Out of 65 individuals screened for scoliotic posture, 38 participants were included in the final analysis (mean age 15.3 years; 19 with structural scoliosis [Cobb ≥ 10°] and 19 with non-structural postural asymmetry). Clinical evaluation included the angle of trunk rotation (ATR) using Bunnell’s scoliometer, the long-sitting test (Derbolovsky test), the standing flexion test, and the Gillet test. Radiological assessment (X-ray) was used to measure the Cobb angle, vertebral rotation (Nash–Moe scale), and LLD. Statistical analysis was performed using Spearman’s rank correlation and comparative tests (Student’s t-test, Welch’s test, and Mann–Whitney U test). Sensitivity analyses were conducted for pediatric participants aged < 18 years (n = 35) and structural scoliosis cases (Cobb ≥ 10°, n = 19) Bonferroni correction was applied for multiple testing (padj). Results: In the total cohort, ATR correlated moderately with radiographic LLD (rs = 0.40, padj = 0.041) and pelvic height difference (rs = 0.40, padj = 0.04). However, these primary associations attenuated and lost statistical significance in both the under-18 (padj = 0.114 and padj = 0.128) and structural scoliosis (padj = 0.271 and padj = 0.279) subgroups. Conversely, the association between ATR and absolute leg-length difference remained robust and statistically significant in the under-18 subgroup (rs = 0.50, padj = 0.021). Lower limb asymmetry indicators showed no significant correlations with the Cobb angle across any analyses (padj = 1.000). Clinical pelvic tests did not differentiate ATR or Cobb values, but left-sided positives were associated with significantly greater cervical lordosis (padj < 0.025). Conclusions: Scoliometer measurements reflect surface trunk rotation rather than structural curve severity (Cobb angle). Primary LLD associations with ATR are sensitive to cohort maturity and curve structurality, losing significance in subgroup analyses. Only absolute leg-length difference maintained a robust association with ATR in the adolescent cohort. Clinical interpretation of scoliometer findings must account for lower limb posture while recognizing that surface asymmetry does not directly mirror structural scoliosis magnitude.

Source: Journal of Clinical Medicine

DOI: 10.3390/jcm15208065