76 ± 11.33%, p = 0.012 in ELD; 7.44 ± 9.43%, p < 0.001 in ALF), the increase was significantly less in the ELD group than in the ALF group (p = 0.049) ( Fig. 2). Collectively, these results suggest that ELD maintained the biomechanical properties of the femoral neck more effectively. The percentage changes in BMD, bone geometry, and biomechanical properties in the femoral shaft were compared between the ELD

group and the ALF group (Fig. 3). Cortical vBMD in the shaft decreased significantly in PF-562271 mouse both the ELD group (− 10.13 ± 4.54%, p < 0.001) and the ALF group (− 11.85 ± 4.58%, p < 0.001) ( Fig. 3); however, the percentage decrease was significantly smaller in the ELD group than in the ALF group (p = 0.026). Although the total area increased significantly from baseline in both the ELD and ALF groups, the bone area of the femoral shaft increased significantly only in the ELD group (1.75 ± 3.24%, p < 0.001). Outer perimeter increased significantly from baseline in both treatment groups (0.92 ± 1.67%, p < 0.001 in ELD; 0.94 ± 2.22%, p < 0.001 in ALF), with no difference between the two groups. Inner perimeter increased significantly in both groups (0.76 ± 2.75%, p = 0.023 in ELD;

1.85 ± 3.52%, p < 0.001 in ALF); however, Dabrafenib the percentage increase was significantly greater in the ALF group than in the ELD group (p = 0.042). CSMI in the femoral shaft increased significantly from baseline in both the ELD and ALF groups. Thus, although there was no difference between groups with respect to this biomechanical parameter, the increase in Regorafenib order inner perimeter, presumably due to accelerated resorption, was more effectively prevented by ELD.

A recent randomized, double-blind study to compare the effects of ELD with ALF demonstrated the superiority of ELD over the active comparator, especially with respect to non-vertebral fractures [20]. In order to gain insight into the biomechanical basis underlying this clinically verified anti-fracture action of ELD, we took a subgroup of the randomized study and used clinical MDCT scanning to compare the effects of ELD and ALF on the 3D structure of the proximal femur, focusing particularly on the cortical component and biomechanical properties. Our study not only revealed the distinct action of ELD on the cortical compartment but also provided evidence for the improvement of biomechanical properties. In the femoral neck, whereas cross-sectional cortical thickness decreased in the ALF group, it was maintained in the ELD group. Taken together with the results that the cortical perimeter increased in both the ALF and ELD groups, it is suggested that ELD was more effective than ALF in countering endocortical bone resorption, thereby maintaining cortical thickness. This is also consistent with the trend for increased CSA by ELD. Fig. 4 schematically illustrates the distinct actions of ELD and ALF on the cortical geometry and density of the femoral neck and shaft.