Center for Advanced Orthopedic Studies, Beth Israel Deaconess Medical Center, and Department of Orthopedic Surgery, Harvard Medical School, Boston, MA, USA.
ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland.
Osteoporos Int. 2020 Mar;31(3):393-408. doi: 10.1007/s00198-019-05195-0. Epub 2020 Jan 3.
We reviewed the experimental and clinical evidence that hip bone strength estimated by BMD and/or finite element analysis (FEA) reflects the actual strength of the proximal femur and is associated with hip fracture risk and its changes upon treatment.
The risk of hip fractures increases exponentially with age due to a progressive loss of bone mass, deterioration of bone structure, and increased incidence of falls. Areal bone mineral density (aBMD), measured by dual-energy X-ray absorptiometry (DXA), is the most used surrogate marker of bone strength. However, age-related declines in bone strength exceed those of aBMD, and the majority of fractures occur in those who are not identified as osteoporotic by BMD testing. With hip fracture incidence increasing worldwide, the development of accurate methods to estimate bone strength in vivo would be very useful to predict the risk of hip fracture and to monitor the effects of osteoporosis therapies.
We reviewed experimental and clinical evidence regarding the association between aBMD and/orCT-finite element analysis (FEA) estimated femoral strength and hip fracture risk as well as their changes with treatment.
Femoral aBMD and bone strength estimates by CT-FEA explain a large proportion of femoral strength ex vivo and predict hip fracture risk in vivo. Changes in femoral aBMD are strongly associated with anti-fracture efficacy of osteoporosis treatments, though comparable data for FEA are currently not available.
Hip aBMD and estimated femoral strength are good predictors of fracture risk and could potentially be used as surrogate endpoints for fracture in clinical trials. Further improvements of FEA may be achieved by incorporating trabecular orientations, enhanced cortical modeling, effects of aging on bone tissue ductility, and multiple sideway fall loading conditions.
我们回顾了实验和临床证据，这些证据表明髋骨骨密度（BMD）和/或有限元分析（FEA）估计的骨强度反映了股骨近端的实际强度，并与髋部骨折风险及其治疗后的变化相关。
由于骨量逐渐减少、骨结构恶化以及跌倒发生率增加，髋部骨折的风险随着年龄的增长呈指数级增加。双能 X 射线吸收法（DXA）测量的面积骨密度（aBMD）是骨强度最常用的替代标志物。然而，与年龄相关的骨强度下降超过了 aBMD 的下降，并且大多数骨折发生在那些通过 BMD 测试未被诊断为骨质疏松症的人群中。随着全球髋部骨折发病率的增加，开发准确的方法来体内估计骨强度将非常有助于预测髋部骨折的风险，并监测骨质疏松症治疗的效果。
我们回顾了关于 aBMD 和/或 CT-FEA 估计的股骨强度与髋部骨折风险之间的关联以及它们随治疗变化的实验和临床证据。
股骨 aBMD 和 CT-FEA 估计的骨强度解释了体外股骨强度的很大一部分，并预测了体内髋部骨折的风险。股骨 aBMD 的变化与骨质疏松症治疗的抗骨折疗效密切相关，尽管目前尚无类似的 FEA 数据。
髋部 aBMD 和估计的股骨强度是骨折风险的良好预测指标，可能被用作临床试验中骨折的替代终点。通过纳入小梁取向、增强皮质建模、骨组织延展性随年龄变化的影响以及多种侧向跌倒加载条件，FEA 可能会进一步改进。
