Association Between Pelvic Asymmetry, Hip Joint Proprioception and Low Back Pain Severity in Patients with Lumbar Radiculopathy: A Cross-Sectional Comparative Study

Background: Lumbar radiculopathy (LR) is a clinical condition characterized by dysfunction of the lumbar nerve roots, often associated with nerve root compression, and commonly presents with low back pain (LBP). Pelvic asymmetry (PA) is characterized by frontal-plane pelvic obliquity (PO) and pelvic tilt asymmetry, defined as the side-to-side difference in the anterior superior iliac spine (ASIS)–posterior superior iliac spine (PSIS) angle in the sagittal plane. This asymmetry may be associated with alterations in lumbopelvic–hip biomechanics and mechanical load distribution across the lumbar spine, pelvis, and hip joints. Accurate proprioceptive feedback from the hip joint is essential for dynamic joint stability and coordinated lower-limb movement. However, the relationships among PA hip joint proprioception, and pain severity in patients with lumbar radiculopathy remain unclear. This study aimed to compare hip joint position error (JPE) and LBP intensity between patients with and without PA and to examine the correlations between pelvic alignment measures, hip joint JPE, and pain intensity. Methods: Sixty-four patients of either gender, aged 25–45 years, with LR due to lumbar disc herniation and presenting with LBP and unilateral radiating lower-extremity pain, were consecutively recruited. Participants were classified according to predefined cutoff values for PO and pelvic tilt asymmetry into two groups of 32: Group A (without PA) and Group B (with PA). Pelvic alignment was assessed using standardized photographs analyzed with Kinovea motion analysis software. Hip joint position sense was assessed using an isokinetic dynamometer, and LBP intensity was measured using the Numerical Pain Rating Scale (NPRS). Results: Patients in Group B demonstrated significantly greater JPE across all tested movements (flexion, abduction, and internal rotation) and higher pain intensity than patients in Group A (p < 0.05). Within Group B, pelvic obliquity was positively correlated with hip flexion, abduction, and internal rotation JPE (r = 0.47, 0.54, and 0.58, respectively; p < 0.05), but not with pain intensity (r = 0.30, p = 0.09). Pelvic tilt asymmetry was positively correlated with hip flexion JPE (r = 0.36), abduction JPE (r = 0.56), and pain intensity (r = 0.48) (all p < 0.05), but not with internal rotation JPE (r = 0.02, p = 0.91). Conclusions: Pelvic asymmetry is associated with greater hip joint position error, suggesting impaired hip joint position sense, and with higher pain intensity in patients with lumbar radiculopathy. However, the cross-sectional design precludes causal inferences. Longitudinal studies are warranted to further investigate these relationships.