Updating radiographic parameters for the healthy growing hip: are current parameters still valid?

Background This study aimed to evaluate whether the acetabular angle (AA) by Tönnis and lateral center–edge angle (LCEA) by Wiberg—key radiographic parameters in pediatric hip assessment—have changed in a contemporary pediatric population compared with historical reference values, considering trends in earlier skeletal maturation and body composition. Materials and methods This retrospective diagnostic accuracy study assessed changes in AA and center–edge angle (CE) angles in a contemporary cohort. A total of 1774 anteroposterior pelvic radiographs (3548 hips) from patients aged 0–18 years without hip pathology were analyzed. Radiographs were obtained between 2006 and 2018 and measured using the Supervisely digital platform. Standardized anatomical landmarks were applied. Data were stratified by age and sex and compared with historical values using two-sample t-tests (p 0.05). In contrast, LCEAs were significantly higher in the contemporary cohort, especially in the 5–8, 9–12, and 12–16 age groups (all p < 0.01), indicating a trend toward earlier or increased acetabular ossification and femoral head coverage. Conclusions LCEA values were significantly higher in the contemporary pediatric cohort compared with historical data, while AA values remained stable across most age groups. These findings suggest that current radiographic reference standards for LCEA may warrant reassessment to ensure accurate dysplasia assessment. Level of evidence: level 3 (diagnosis).