Computational Biomechanics Laboratory, University of Denver, Denver, CO 80208, USA.
J Biomech. 2011 Sep 2;44(13):2446-52. doi: 10.1016/j.jbiomech.2011.06.025. Epub 2011 Jul 30.
Patellofemoral (PF)-related pathologies, including joint laxity, patellar maltracking, cartilage degradation and anterior knee pain, affect nearly 25% of the population. Researchers have investigated the influence of articular geometry on kinematics and contact mechanics in order to gain insight into the etiology of these conditions. The purpose of the current study was to create a three-dimensional statistical shape model of the PF joint and to characterize relationships between PF shape and function (kinematics and contact mechanics). A statistical shape model of the patellar and femoral articular surfaces and their relative alignment was developed from magnetic resonance images. Using 15 shape parameters, the model characterized 97% of the variation in the training set. The first three shape modes primarily described variation in size, patella alta-baja and depth of the sulcus groove. A previously verified finite element model was used to predict kinematics and contact mechanics for each subject. Combining the shape and joint mechanics data, a statistical shape-function model was developed that established quantitative relations of how changes in the shape of the PF joint influence mechanics. The predictive capability of the shape-function model was evaluated by comparing statistical model and finite element predictions, resulting in kinematic root mean square errors of less than 3° and 2.5 mm. The key results of the study are dually in the implementation of a novel approach linking statistical shape and finite element models and the relationships elucidated between PF articular geometry and mechanics.
髌股（PF）相关疾病，包括关节松弛、髌骨轨迹不良、软骨退化和前膝痛，影响了近 25%的人群。研究人员研究了关节几何形状对运动学和接触力学的影响，以深入了解这些疾病的病因。本研究的目的是创建 PF 关节的三维统计形状模型，并描述 PF 形状与功能（运动学和接触力学）之间的关系。从磁共振图像中开发了髌股关节和股骨关节表面及其相对对齐的统计形状模型。该模型使用 15 个形状参数，可描述 97%的训练集的变化。前三个形状模式主要描述了大小、髌骨高低和沟裂深度的变化。使用先前验证的有限元模型预测每个受试者的运动学和接触力学。结合形状和关节力学数据，开发了一个统计形状-功能模型，建立了 PF 关节形状变化如何影响力学的定量关系。通过比较统计模型和有限元预测，评估形状-功能模型的预测能力，结果运动学均方根误差小于 3°和 2.5 毫米。该研究的主要结果是双重的，即实施了一种新的方法，将统计形状和有限元模型联系起来，并阐明了 PF 关节几何形状与力学之间的关系。
