Impact of Childhood Obesity on Capital Femoral Epiphysis Morphology: A Large-Scale, Automated 3D-CT Study and Potential Implications for SCFE Pathogenesis.

BACKGROUND The precise pathological mechanisms through which obesity increases the risk of slipped capital femoral epiphysis (SCFE) remain unclear. We aimed to investigate the impact of childhood obesity on the morphology of the capital femoral epiphysis in children and adolescents without hip disorders. METHODS We performed a retrospective cross-sectional study that included 4,888 children and adolescents 7 to 19 years of age who underwent a hip or pelvic computed tomography (CT) scan, most for abdominal pain, between 2004 and 2022. Automated 3D-CT analysis assessed epiphyseal tubercle height, superior and anterior peripheral cupping, and epiphyseal tilt. Generalized additive models (GAMs) were used to examine the associations between epiphyseal morphology and age, stratified by obesity status, while adjusting for sex. RESULTS We observed distinct age-related trajectories of femoral-head morphology related to obesity. Subjects with obesity demonstrated a larger femoral-head diameter from ages 7 to 15 years (obese versus normal-weight differences: 0.3 to 2.3 mm), smaller epiphyseal tubercle height after 9 years of age (normal-weight versus obese differences: 0.4% to 1.3%), and a more posteriorly tilted epiphysis, as assessed by a smaller axial tilt angle (normal-weight versus obese differences: 4° to 1°) from ages 7 to 15 years. In subjects with obesity, the superior epiphyseal cupping was larger before 11 years of age (obese versus normal-weight differences: 1.6% to 0.4%), but after 13 years of age, the superior epiphyseal cupping was smaller (normal-weight versus obese differences: 0.2% to 2%). CONCLUSIONS Children with obesity demonstrated a smaller epiphyseal tubercle height, greater posterior epiphyseal tilt, and reduced superior cupping compared with children of normal weight. These anatomical differences may contribute to the increased risk of SCFE in patients with obesity and offer potential imaging markers for earlier identification and risk-stratification. LEVEL OF EVIDENCE Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.