Vertebral fracture risk and alendronate effects on osteoporosis assessed by a computed tomography-based nonlinear finite element method.

Computed tomography-based nonlinear finite element method (CT/FEM) can accurately predict vertebral compressive strength ex vivo and this method is clinically available in vivo. This study aimed to assess vertebral fracture risk and alendronate effects on osteoporosis in vivo using CT/FEM. Vertebral strength in 123 postmenopausal women was analyzed and the discriminatory power for vertebral fracture was assessed cross-sectionally. Alendronate effects were also prospectively assessed in 33 patients with postmenopausal osteoporosis who were treated with alendronate at a dose of 5 mg/day for 18 months. CT/FEM had higher discriminatory power for vertebral fracture than areal bone mineral density (BMD) and volumetric BMD and detected alendronate effects at 3 months. Marked bone density increases were noted in juxtacortical areas compared to inner trabecular areas. CT/FEM was useful for assessing vertebral fracture risk and therapeutic effects on osteoporosis.