Edwards W Brent, Ward Erin D, Meardon Stacey A, Derrick Timothy R
Department of Kinesiology, Iowa State University, Ames, IA 50011, USA.
J Biomech Eng. 2009 May;131(5):051009. doi: 10.1115/1.3118762.
Noninvasive methods for monitoring the in vivo loading environment of human bone are needed to determine osteogenic loading patterns that reduce the potential for bone injury. The purpose of this study was to determine whether the vertical ground reaction impact force (impact force) and leg acceleration could be used to estimate internal bone strain at the distal tibia during impact activity. Impact loading was delivered to the heels of human-cadaveric lower extremities. The effects of impact mass and contact velocity on peak bone strain, impact force, leg acceleration, and computed impact force (leg acceleration *impact mass) were investigated. Regression analysis was used to predict bone strain from six different models. Apart from leg acceleration, all variables responded to impact loading similarly. Increasing impact mass resulted in increased bone strain, impact force, and computed impact force, but decreased leg acceleration. The best models for bone strain prediction included impact force and tibial cross-sectional area (R(2)=0.94), computed impact force and tibial cross-sectional area (R(2)=0.84), and leg acceleration and tibial cross-sectional area (R(2)=0.73). Results demonstrate that when attempting to estimate bone strain from external transducers some measure of bone strength must be considered. Although it is not recommended that the prediction equations developed in this study be used to predict bone strain in vivo, the strong relationship between bone strain, impact force, and computed impact force suggested that force platforms and leg accelerometers can be used for a surrogate measure of bone strain.
需要非侵入性方法来监测人体骨骼的体内负荷环境，以确定可降低骨损伤可能性的成骨负荷模式。本研究的目的是确定垂直地面反作用力（冲击力）和腿部加速度是否可用于估计冲击活动期间胫骨远端的内部骨应变。对人体尸体下肢的足跟施加冲击负荷。研究了冲击质量和接触速度对峰值骨应变、冲击力、腿部加速度和计算冲击力（腿部加速度×冲击质量）的影响。使用回归分析从六种不同模型预测骨应变。除腿部加速度外，所有变量对冲击负荷的反应相似。增加冲击质量会导致骨应变、冲击力和计算冲击力增加，但腿部加速度降低。预测骨应变的最佳模型包括冲击力和胫骨横截面积（R² = 0.94）、计算冲击力和胫骨横截面积（R² = 0.84）以及腿部加速度和胫骨横截面积（R² = 0.73）。结果表明，当试图通过外部传感器估计骨应变时，必须考虑某种骨强度测量方法。尽管不建议使用本研究中开发的预测方程来预测体内骨应变，但骨应变、冲击力和计算冲击力之间的强相关性表明，力平台和腿部加速度计可用于替代骨应变测量。
