Effect of age and sex on femoral curvature in the Japanese population: three-dimensional computed tomography findings

Age- or sex-related differences in femoral curvature affect the onset of trauma or degenerative diseases of the hip joints. This study aimed to investigate femoral curvature in detail in Japanese individuals using three-dimensional computed tomography, evaluate its effects on the position of proximal femur, and assess differences in femoral curvature according to age and sex. We measured sagittal and coronal femoral bowing in 40 elderly (mean age 85.2 years) and 40 adult (mean age 30.1 years) Japanese individuals using computed tomography. In adult individuals, the radii of the femoral curvatures of the distal end and shaft in the coronal planes were significantly smaller in women than in men. In contrast, no significant difference was observed in femoral curvature between the sexes in the elderly group. Furthermore, the radius of femoral curvature was significantly smaller in elderly individuals than in adult individuals, regardless of the sex and location of the measurement. The highest point of the greater trochanter of the femoral head center was 7.3 +/- 5.6 mm in the elderly group and 2.2 +/- 4.6 mm in the adult group (p < 0.05). Thus, the femoral curvature varies with age and sex in Japanese individuals. In addition, the femoral curvature could cause positional changes in the proximal femur, such as the highest point of the greater trochanter. Therefore, further studies investigating the biomechanical effects of these morphological changes are warranted.