Risk of scoliosis following hip disease: a 10-year nationwide cohort study in South Korea

BACKGROUND: The biomechanical linkage between the hip and spine suggests that hip disorders may contribute to secondary spinal deformities such as scoliosis, but longitudinal population-based evidence is limited. This study examined the long-term risk of adult scoliosis following different types of hip disorders using a nationwide South Korean cohort. METHODS: This retrospective matched cohort study used Korean National Health Insurance Service data (2002-2013). Patients with degenerative (n = 5208), inflammatory/infectious (n = 11,215), or traumatic (n = 2765) hip disorders were matched 1:2 to individuals without hip disorders. Incident scoliosis was identified using ICD-10 codes. Adjusted hazard ratios (aHRs) were estimated with multivariable Cox proportional hazards models, with subgroup analyses by age and sex. FINDINGS: Over a 10-year follow-up, scoliosis incidence was higher among patients with hip disorders than among controls. The risk was significantly increased in degenerative hip disorders (aHR 2.12, 95% CI 1.61-2.78) and inflammatory/infectious hip disorders (aHR 1.68, 95% CI 1.34-2.11). Traumatic hip disorders showed a non-significant association (aHR 1.49, 95% CI 0.99-2.24). Higher relative risks were generally observed in younger patients and males, particularly in the degenerative hip disorder group. INTERPRETATION: Degenerative and inflammatory/infectious hip disorders are associated with an increased long-term risk of scoliosis. These findings underscore the need for early spinal evaluation and preventive strategies in patients with hip pathology.