Multiaxial Strength Behavior of Human Trabecular Bone

人体骨小梁的多轴强度行为

基本信息

批准号：
7261390
负责人：
Tony M Keaveny
金额：
$ 31.7万
依托单位：
UNIVERSITY OF CALIFORNIA BERKELEY
依托单位国家：
美国
项目类别：
财政年份：
1996
资助国家：
美国
起止时间：
1996-08-01 至 2011-06-30
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): The strength behavior of human trabecular bone is a critical component in the etiology of age-related osteoporotic fractures. Most hip fractures occur from falls, during which complex multi-directional ("multiaxial") stresses develop. A multiaxial failure criterion is necessary to determine whether or not the bone will fail under such circumstances. We have investigated so far in this project the multiaxial failure properties of high-density trabecular bone and have developed the first ever three-dimensional, complete multiaxial failure criterion. Our goal now is to extend that work to cover trabecular bone of any density. This is important for hip fractures since low density bone exists in many parts of the proximal femur. Other sites of interest include the proximal tibia, with particular relevance to loosening of total knee implants. It has also recently become clear that DXA, the clinical standard for bone strength assessment, has substantial limitations in its ability to predict fracture and monitor drug therapies. Bone turnover has come under intense scrutiny as a potential replacement for bone mass as a predictor of fracture and assessor of therapy, but the biomechanical mechanisms by which bone turnover might affect bone strength are poorly understood. Our second goal in this project is to understand the mechanisms of trabecular multiaxial failure and from this explain the biomechanical link between bone turnover and bone strength. We are proposing that bone turnover affects the remodeling space and that the resulting changes in the distribution of thickness within trabeculae - reflecting changes in resorption cavity geometry and number - should be manifested as changes in the apparent failure (yield) strain and/or density-strength relation of the trabecular bone, an effect that should be accentuated under multiaxial shear-type loading. This is because there is an interaction between the strain amplification effect associated with resorption cavities and the multiaxial shear-type loading conditions that promote excessive bending of individual trabeculae. A series of cadaver studies are planned to address our first goal, and a Series of animal studies using canine and ovine models are planned for the second goal, in which bone turnover is either elevated (by OVX) or depressed (by alendronate treatment). This project should provide substantial insight into the roles of trabecular bone strength and bone quality on osteoporotic fracture risk and treatment and other orthopedic applications.

描述（由申请人提供）：人小梁骨的强度行为是与年龄有关的骨质疏松性骨折的病因中的关键组成部分。大多数髋关节骨折都来自跌倒，在此期间，复杂的多向（“多轴”）应力发生了。必须在这种情况下确定骨头是否会失败的多轴故障标准。到目前为止，我们已经在该项目中调查了高密度小梁骨的多轴故障特性，并开发了有史以来第一个三维完整的多轴故障标准。我们现在的目标是扩展该工作以覆盖任何密度的小梁骨。这对于髋部骨折很重要，因为在股骨近端许多部位存在低密度骨骼。其他感兴趣的部位包括胫骨近端，与膝盖总植入物松动特别相关。最近，最近也很清楚，DXA是骨骼强度评估的临床标准，其预测骨折和监测药物疗法的能力具有很大的限制。作为骨骼质量的潜在替代者，骨骼更新受到了严格的审查，作为骨折和治疗评估者的预测指标，但是骨骼转换可能影响骨强度的生物力学机制知之甚少。我们在该项目中的第二个目标是了解小梁多轴故障的机制，并从此解释骨化和骨骼强度之间的生物力学联系。我们提出，骨骼转换会影响重塑空间，并且应表现为反映陷阱内厚度分布的变化 - 反映吸收腔几何形状和数量的变化 - 应表现为明显的失败（产量）应变（产量）应变（屈服）和/或密度 - 密度长度的变化。这是因为与吸收腔有关的应变扩增效应与多轴剪切型载荷条件之间存在相互作用，从而促进单个小梁的过度弯曲。计划进行一系列尸体研究来解决我们的第一个目标，并计划针对第二个目标进行一系列使用犬和卵巢模型的动物研究，在该目标中，骨骼转换升高（通过OVX）或抑郁症（通过Alendronronate治疗）。该项目应为小梁骨强度和骨质质量在骨质疏松性裂缝风险和治疗以及其他骨科应用中的作用提供大量见解。