Implications of in vivo muscle loading for hip fracture etiology

描述(申请人提供)：项目摘要：肌肉直接影响股骨的活体负荷，正常情况下保护骨骼免受剪切和拉伸应力和应变的破坏。日常活动中与年龄相关的肌肉负荷变化可能会增加股骨近端的疲劳损伤率，从而增加髋部骨折的风险。这项拟议的研究将使用一个独特的计算模型来研究正常行走过程中肌肉负荷对股骨近端应力和应变的影响。这个项目的第一个目标是研究步态中肌肉负荷引起的股骨应力和应变随年龄的变化。第二个目标是量化个体肌肉在步态过程中对股骨应力和应变的贡献。这些信息将有助于了解髋部骨折的原因，从长远来看，可用于改进诊断和预防措施，减少这些使人衰弱的伤害的发生率。将开发一个计算模型来估计步态过程中股骨近端的应力和应变。该模型将结合肌肉骨骼生物力学中广泛使用的两种计算技术：静态优化和有限元建模。将记录10名18-25岁的受试者和10名65-80岁的受试者在步态过程中的运动学和地面反作用力数据。这些数据将使用反向动力学和静态优化进行分析，以确定在整个步态周期中作用于股骨的单个肌力的真实值。将建立股骨的有限元模型，并利用估计的肌力来预测步态过程中股骨近端的应力和应变。峰值应力/应变将在不同年龄组之间进行比较，并进行敏感性分析，以确定每一块肌肉对整体应力/应变状态的重要性。相关性：髋部骨折是当今老年人面临的最严重的医疗问题之一，因为骨折后死亡率和致残率很高。这项研究将研究步态中与年龄相关的肌肉负荷变化如何导致骨骼的虚弱和最终骨折。这些信息可能导致改进筛查技术和预防措施，以减少髋部骨折的发生率。

DESCRIPTION (provided by applicant): Project Summary: Muscles contribute directly to in vivo loading of the femur and normally protect the bone from exposure to damaging levels of shear and tensile stresses and strains. Age-related changes in the muscle loading experienced during daily activities could increase the rate of fatigue damage in the proximal femur, thus increasing the risk of hip fracture. The proposed research will investigate the effect of muscular loading on stresses and strains in the proximal femur during normal walking using a unique computational model. The first aim of this project is to investigate age-related changes in femoral stresses and strains due to muscular loading during gait. The second aim is to quantify the contributions of individual muscles to femoral stresses and strains during gait. This information will contribute to understanding of the causes of hip fractures, and in the long term could be used to improve diagnostic and preventive measures, decreasing the incidence of these debilitating injuries. A computational model will be developed to estimate the stresses and strains in the proximal femur during gait. This model will combine two computational techniques that are widely used in musculoskeletal biomechanics: static optimization and finite element modeling. Kinematics and ground reaction force data during gait will be recorded for 10 subjects ages 18-25 and 10 subjects ages 65-80. This data will be analyzed using inverse dynamics and static optimization to determine realistic values for the individual muscle forces acting on the femur throughout the gait cycle. Finite element models of the femur will be developed and, with the estimated muscle forces, used to predict the stresses and strains in the proximal femur during gait. The peak stresses/strains will be compared between age groups, and a sensitivity analysis performed to determine the importance of each muscle to the overall stress/strain state. Relevance: Hip fractures are one of the most serious healthcare problems facing older adults today due to high rates of post-fracture death and disability. This research will examine how age related changes in muscle loading during gait may contribute to the weakening and eventual fracture of the bone. Such information could lead to improved screening techniques and preventive measures to reduce the incidence of hip fractures.