Progression of idiopathic thoracic or thoracolumbar scoliosis and pelvic obliquity in adolescent patients with and without limb length discrepancy

Βackground Both limb length inequality and scoliosis are associated with pelvic obliquity. Methods This is an observational study of adolescents with growth potential presenting for evaluation of thoracic or thoracolumbar idiopathic scoliosis at an outpatient pediatric orthopedic clinic. Patients were evaluated for limb length discrepancy (LLD) (using bilateral femoral head height difference), pelvic obliquity (using bilateral iliac crest height difference and sacral takeoff angle), and scoliotic curve (using Cobb angle and rotation) on full spine standing radiographs. The same radiographic parameters were measured at a follow-up visit at least 2 years later. Results Seventy-three consecutive patients with a mean (SD) age of 13.3 (0.2) years at initial examination were included in the study. Scoliosis (major curve Cobb angle ≥ 10°) was confirmed in all 73 patients, pelvic obliquity (iliac crest height difference > 1 cm or sacral takeoff angle > 5°) appeared in 23 (31.5%) patients with scoliosis, and LLD (> 1 cm femoral head height difference) was identified in 6 (8.2%) patients with scoliosis and pelvic obliquity. At a subsequent visit, a mean of 2.8 (range 2–5.8) years later, no significant change ( p > 0.05) in limb length inequality was observed but a statistically significant increase ( p < 0.05) in scoliotic and pelvic deformity parameters was found. Conclusions In adolescent patient population with thoracic or thoracolumbar scoliosis, the anisomelia remains stable with growth but both the scoliotic deformity and pelvic obliquity progress. Trial registration MGH no 2012-P-000774/1