Chen Yu-Jen, Scher Irving, Powers Christopher M
Musculoskeletal Biomechanics Research Laboratory, Division of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles, CA, USA.
J Appl Biomech. 2010 Nov;26(4):415-23. doi: 10.1123/jab.26.4.415.
The purpose of this study was to describe an imaging based, subject specific model that was developed to quantify patellofemoral joint reaction forces (PFJRF's). The secondary purpose was to test the model in a group of healthy individuals while performing various functional tasks. Twenty healthy subjects (10 males, 10 females) were recruited. All participants underwent two phases of data collection: 1) magnetic resonance imaging of the knee, patellofemoral joint, and thigh, and 2) kinematic, kinetic and EMG analysis during walking, running, stair ascent, and stair descent. Using data obtained from MRI, a subject specific representation of the extensor mechanism was created. Individual gait data were used to drive the model (via an optimization routine) and three-dimensional vasti muscle forces and subsequent three-dimensional PFJRF's were computed. The average peak PFJRF was found to be highest during running (58.2 N/kg-bwt), followed by stair ascent (33.9 N/kg-bwt), stair descent (27.9 N/kg-bwt), and walking (10.1 N/kg-bwt). No differences were found between males and females. For all conditions, the direction of the PFJRF was always in the posterior, superior, and lateral directions. The posterior component of the PFJRF always had the greatest magnitude, followed by superior and lateral components. Our results indicate that estimates of the magnitude and direction of the PFJRF during functional tasks can be obtained using a 3D-imaging based model.
本研究的目的是描述一个基于成像的、针对个体的模型，该模型用于量化髌股关节反应力（PFJRF）。次要目的是在一组健康个体执行各种功能任务时对该模型进行测试。招募了20名健康受试者（10名男性，10名女性）。所有参与者都经历了两个数据收集阶段：1）对膝盖、髌股关节和大腿进行磁共振成像，以及2）在行走、跑步、上楼梯和下楼梯过程中进行运动学、动力学和肌电图分析。利用从MRI获得的数据，创建了伸肌机制的个体特异性表示。个体步态数据用于驱动模型（通过优化程序），并计算三维股四头肌力量和随后的三维PFJRF。发现平均峰值PFJRF在跑步时最高（58.2 N/kg体重），其次是上楼梯（33.9 N/kg体重）、下楼梯（27.9 N/kg体重）和行走（10.1 N/kg体重）。男性和女性之间未发现差异。在所有情况下，PFJRF的方向始终在后、上和外侧方向。PFJRF的后向分量总是具有最大的大小，其次是上向和外侧分量。我们的结果表明，使用基于三维成像的模型可以获得功能任务期间PFJRF大小和方向的估计值。
