Myers Casey A, Fitzpatrick Clare K, Huff Daniel N, Laz Peter J, Rullkoetter Paul J
Center for Orthopaedic Biomechanics, University of Denver, Denver, CO, USA.
Mechanical and Biomedical Engineering, Boise State University, Boise, ID, USA.
Comput Methods Biomech Biomed Engin. 2020 Aug;23(11):755-764. doi: 10.1080/10255842.2020.1764543. Epub 2020 May 20.
The objective of this study was to develop a probabilistic representation of the hip capsule, which is calibrated to experimental capsular torque-rotation behavior and captures the observed variability for use in population-based studies. A finite element model of the hip capsule was developed with structures composed of a fiber-reinforced membrane, represented by 2D quadrilateral elements embedded with tension-only non-linear spring. An average capsule representation was developed by calibrating ligament properties (linear stiffness, reference strain) so that torque-rotation behavior matched mean cadaveric data. A probabilistic capsule was produced by determining the ligament property variability which represented ±2 SD measured in the experiment. Differences between experimental and model kinematics across all positions had RMS error of 4.7°. Output bounds from the optimized probabilistic capsule representation were consistent with ±2 SD of experimental data; the overall RMS error was 5.1°. This model can be employed in population-based finite element studies of THA to assess mechanics in realistic scenarios considering implant design, as well as surgical and patient factors.
本研究的目的是建立髋关节囊的概率表示模型，该模型根据实验性囊扭矩-旋转行为进行校准，并捕捉观察到的变异性，以用于基于人群的研究。开发了一个髋关节囊的有限元模型，其结构由纤维增强膜组成，用嵌入仅受拉非线性弹簧的二维四边形单元表示。通过校准韧带特性（线性刚度、参考应变）来建立平均囊表示模型，以使扭矩-旋转行为与平均尸体数据相匹配。通过确定代表实验中测量的±2标准差的韧带特性变异性来生成概率性囊模型。所有位置的实验和模型运动学之间的差异的均方根误差为4.7°。优化后的概率性囊表示模型的输出范围与实验数据的±2标准差一致；总体均方根误差为5.1°。该模型可用于基于人群的全髋关节置换有限元研究，以评估在考虑植入物设计以及手术和患者因素的现实场景中的力学情况。
