Mechanical strength of the femoral neck. Mechanical results of femoral neck fractures in sham control rats, and OVX rats that received saline, alendronate (ALN), calcitriol (VitD), or combined alendronate and calcitriol treatments (ALN+VitD) for 12 weeks. The data are presented as mean ± SD (n = 6 per group). # P < 0.05 as compared with corresponding values in saline-treated OVX (unpaired t-test).* P < 0.05 as compared with corresponding values in saline-treated OVX (Tukey's multiple comparison test). Bone strength of the femoral neck was significantly lower in the saline-treated OVX compared with the sham group. The bone strength in OVX rats was significantly improved by the combined alendronate and calcitriol treatment but not by alendronate or calcitriol single treatment.