Fyhrie David P, Christiansen Blaine A
Department of Orthopaedic Surgery, University of California-Davis Medical Center, 4635 2nd Ave, Suite 2000, Sacramento, CA, 95817, USA,
Calcif Tissue Int. 2015 Sep;97(3):213-28. doi: 10.1007/s00223-015-9997-1. Epub 2015 May 5.
Deformations of vertebrae and sudden fractures of long bones caused by essentially normal loading are a characteristic problem in osteoporosis. If the loading is normal, then the explanation for and prediction of unexpected bone failure lies in understanding the mechanical properties of the whole bone-which come from its internal and external geometry, the mechanical properties of the hard tissue, and from how well the tissue repairs damage. Modern QCT and MRI imaging systems can measure the geometry of the mineralized tissue quite well in vivo-leaving the mechanical properties of the hard tissue and the ability of bone to repair damage as important unknown factors in predicting fractures. This review explains which material properties must be measured to understand why some bones fail unexpectedly despite our current ability to determine bone geometry and bone mineral content in vivo. Examples of how to measure the important mechanical properties are presented along with some analysis of potential drawbacks of each method. Particular attention is given to methods useful to characterize the loss of bone toughness caused by mechanical fatigue, drug side effects, and damage to the bone matrix.
在骨质疏松症中，基本正常的负荷导致椎骨变形和长骨突然骨折是一个典型问题。如果负荷正常，那么对于意外骨衰竭的解释和预测在于理解整个骨骼的力学性能，而这又取决于其内部和外部几何形状、硬组织的力学性能以及组织修复损伤的能力。现代定量计算机断层扫描（QCT）和磁共振成像（MRI）系统能够在体内很好地测量矿化组织的几何形状，这使得硬组织的力学性能以及骨骼修复损伤的能力成为预测骨折时重要的未知因素。本综述解释了为理解为何尽管我们目前有能力在体内确定骨几何形状和骨矿物质含量，但仍有一些骨骼会意外骨折，必须测量哪些材料特性。文中给出了测量重要力学性能的方法示例，并对每种方法的潜在缺点进行了一些分析。特别关注了有助于表征由机械疲劳、药物副作用和骨基质损伤导致的骨韧性丧失的方法。
