Upper Femur Anatomy Depends on Age and Gender: A Three-Dimensional Computed Tomography Comparative Bone Morphometric Analysis of 628 Healthy Patients' Hips

Background: The knowledge of proximal femur geometry is essential in the understanding and treatment of hip pathologies. Our aim is to evaluate the range of normal anatomical values of the proximal femur and their relationship to age, gender, and ethnicity in a cohort of healthy population, using a 3-dimensional computed tomography automated software. Methods: The pelvis and bilateral femora of 628 healthy individuals (394 males/234 females, mean age 61.5 +/- 16.5 years, mean body mass index [BMI] 26.9 +/- 5.2 kg/m(2)) including 2 ethnicities (226 Asians and 406 Caucasians) were assessed with a 3-dimensional computed tomography scan-based system using algorithm-calculated landmarks. The demographic parameters recorded were age, gender, BMI, and ethnicity. The femoral neck-shaft angle (NSA), femoral neck version, femoral offset (FO), and femoral canal flare index (fCFI) were calculated for each individual. Analyses were performed using SPSS version 22. P-values <.05 were considered to indicate statistical significance. Results: Overall, the mean NSA was 124.7 degrees (standard deviation [SD] 6.2), mean femoral neck version was 14.5 degrees (SD 8.1), mean FO was 42.9 mm (SD 6.8), and mean fCFI was 3.4 (SD 0.5). Gender was associated with all parameters, with the females presenting more valgus and anteverted hips. Multivariate analysis revealed a lower NSA and fCFI and a higher FO for older individuals. Ethnicity and BMI were not associated with any parameters. Conclusion: Our results showed that there is a direct relationship of age and gender to the variations in the investigated proximal femur anatomical parameters in a large cohort of healthy individuals. Those important gender-based and age-based differences might advocate for more varus and lateralized component to reproduce preoperative anatomy of male and patients older than 50 years. (C) 2019 Elsevier Inc. All rights reserved.