Predicting Hip Fracture Using a Biomechanical Approach

描述（由申请人提供）：髋部骨折是老年人残疾和死亡的重要原因。诊断骨质疏松症和预测骨折风险的最常用工具是通过双能X射线吸收测定法测量的骨矿物质密度（BMD）。然而，高达一半的人患有髋部骨折没有骨质疏松症的骨密度测试，因此，骨折风险评估的替代方法是必要的。这强调了寻找骨折风险的其他因素的重要性，例如转子处的软组织厚度减少，这减弱了可能导致骨折的坠落力。根据生物力学原理，当所施加的力与骨强度的比率（称为“风险因素”）超过1时，就会发生骨折。之前的两项研究已经检查了风险因素沿着转子软组织厚度，但只有少数髋关节骨折，结果相互矛盾。为了更好地了解与髋部骨折相关的因素，我们建议使用生物力学方法来评估髋部骨折风险，包括侧向跌倒期间施加到髋部的估计力以及股骨近端的强度。具体目标是调查股骨转子软组织厚度对髋部骨折风险的影响，并将其纳入生物力学风险因素模型。我们假设这些因素可以预测髋部骨折，并且进一步证明髋部骨折风险因素预测优于单独的BMD评估，优于世界卫生组织FRAX工具。我们将从三个队列（Frachial研究、MrOS、Rancho Bernardo研究）中确定前瞻性确定的髋部骨折病例，并从每个队列中选择最多4名性别和年龄匹配（3年内）的非骨折队列成员作为对照，使用病例队列研究设计以提高效率。2,435例患者的软组织厚度将 评估每个队列在任何后续髋部骨折发生前最早时间获得的全身DXA扫描。使用条件logistic回归将相对风险评估为比值比。这项研究有可能显著改变目前评估髋关节脱位风险的方式，从而改变如何选择患者进行药物治疗。

DESCRIPTION (provided by applicant): Hip fractures are a significant cause of disability and mortality in older persons. The most common tool for diagnosis of osteoporosis and prediction of fracture risk is bone mineral density (BMD) measured by dual- energy X-ray absorptiometry. Yet, up to half of individuals suffering a hip fracture do not have osteoporosis by BMD testing; thus alternative approaches to fracture risk assessment are needed. This underscores the importance of looking for additional contributors to fracture risk, such as reduced soft tissue thickness at the trochanter, which attenuates the fall forces that may lead to fracture. According to biomechanical principles, when the ratio of applied force to bone strength, (termed the 'Factor-of-Risk'), exceeds one, a fracture will occur. Two previous studies have examined the Factor-of-Risk along with trochanteric soft tissue thickness but had only small numbers of hip fractures, and conflicting results. To better understand the factors associated with hip fracture, we propose to use a biomechanical approach to assess hip fracture risk that includes both estimated forces applied to the hip during a sideways fall as well as the strength of the proximal femur. The specific goal is to investigate the contribution of trochanteric soft tissue thickness t hip fracture risk, and to include this in the biomechanical Factor-of-Risk model. We hypothesize these factors predict hip fracture, and further that the factor-of-risk prediction of hip fracture isk will prove better than BMD assessment alone and better than the World Health Organization FRAX tool. We will identify prospectively ascertained hip fracture cases from three cohorts (Framingham Study, MrOS, Rancho Bernardo Study) and from each cohort also select up to four sex- and age-matched (within 3-years) non-fracture cohort members as controls, using the case-cohort study design to increase efficiency. Soft tissue thickness in 2,435 individuals will be assess on whole body DXA scans obtained at the earliest time in each cohort before any subsequent hip fracture occurred. Relative risks will be assessed as odds ratios using conditional logistic regression. This study has potential to significantly alter the way hip fractue risk is currently being assessed, and thus how patients are selected for drug therapy.