Bei Yanhong, Fregly Benjamin J
Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL 32611-6250, USA.
Med Eng Phys. 2004 Nov;26(9):777-89. doi: 10.1016/j.medengphy.2004.07.004.
Multibody dynamic musculoskeletal models capable of predicting muscle forces and joint contact pressures simultaneously would be valuable for studying clinical issues related to knee joint degeneration and restoration. Current three-dimensional multibody knee models are either quasi-static with deformable contact or dynamic with rigid contact. This study proposes a computationally efficient methodology for combining multibody dynamic simulation methods with a deformable contact knee model. The methodology requires preparation of the articular surface geometry, development of efficient methods to calculate distances between contact surfaces, implementation of an efficient contact solver that accounts for the unique characteristics of human joints, and specification of an application programming interface for integration with any multibody dynamic simulation environment. The current implementation accommodates natural or artificial tibiofemoral joint models, small or large strain contact models, and linear or nonlinear material models. Applications are presented for static analysis (via dynamic simulation) of a natural knee model created from MRI and CT data and dynamic simulation of an artificial knee model produced from manufacturer's CAD data. Small and large strain natural knee static analyses required 1 min of CPU time and predicted similar contact conditions except for peak pressure, which was higher for the large strain model. Linear and nonlinear artificial knee dynamic simulations required 10 min of CPU time and predicted similar contact force and torque but different contact pressures, which were lower for the nonlinear model due to increased contact area. This methodology provides an important step toward the realization of dynamic musculoskeletal models that can predict in vivo knee joint motion and loading simultaneously.
能够同时预测肌肉力量和关节接触压力的多体动态肌肉骨骼模型，对于研究与膝关节退变和恢复相关的临床问题具有重要价值。当前的三维多体膝关节模型要么是具有可变形接触的准静态模型，要么是具有刚性接触的动态模型。本研究提出了一种计算效率高的方法，将多体动态模拟方法与可变形接触膝关节模型相结合。该方法需要准备关节表面几何形状，开发计算接触表面之间距离的有效方法，实现考虑人体关节独特特性的高效接触求解器，以及指定用于与任何多体动态模拟环境集成的应用程序编程接口。当前的实现方式适用于自然或人工胫股关节模型、小应变或大应变接触模型以及线性或非线性材料模型。文中展示了对由MRI和CT数据创建的自然膝关节模型进行静态分析（通过动态模拟）以及对由制造商的CAD数据生成的人工膝关节模型进行动态模拟的应用。小应变和大应变自然膝关节静态分析需要1分钟的CPU时间，除了峰值压力外预测的接触条件相似，大应变模型的峰值压力更高。线性和非线性人工膝关节动态模拟需要10分钟的CPU时间，预测的接触力和扭矩相似，但接触压力不同，非线性模型的接触压力因接触面积增加而较低。该方法朝着实现能够同时预测体内膝关节运动和负荷的动态肌肉骨骼模型迈出了重要一步。
