Normal values of femoral head coverage angles on three-dimensional computed tomography images

Introduction Identifying novel diagnostic parameters is essential to address the inaccuracies related to femoral head coverage angle measurements using conventional methods. This study aimed to propose new femoral head coverage landmarks on 3D pelvic CT images in a Korean population and to present reference values based on these landmarks. Methods This single-center retrospective cohort study defined the center, lateral, anterior, and posterior margins of the acetabulum from three-dimensional (3D) pelvic computed tomography (CT) scans of healthy Korean individuals. The lateral center-edge angle (LCEA), anterior center-edge angle (ACEA), posterior center-edge angle (PCEA), anterior acetabular sector angle (AASA), and posterior acetabular sector angle (PASA) were measured in 3D space. Results The normal values for 3D LCEA in Korean males and females were 34.8° (SD = 8.3°) and 32.0° (SD = 6.9°), respectively. The 3D angles measured showed significant variations according to sex and age, with center-edge angles (LCEA, ACEA, and PCEA) generally increasing with age, whereas sector angles (AASA and PASA) showed a decreasing trend. Conclusion The standardized values and statistical findings based on sex and age provided in this study offer valuable references for guiding surgical interventions in the acetabulum. Also, the proposed method yielded more likely to be reliable results than traditional two-dimensional methods with substantial differences.