Morphological and Biomechanical Insights into the Pathophysiology of Femoroacetabular Impingement Syndrome

项目总结 据估计，髋臼撞击综合征(FAIS)占髋关节骨关节炎的82% (OA)病例。FAIS患者表现为股骨头球形丧失，股骨颈偏移量减少， 和/或过度突出的髋臼壁。患者报告的疼痛与位置或运动有关。通常， 软骨从骨骼中剥离，唇骨撕裂。FAIS病理生理学的理论是 病理解剖学导致病理力学。然而，我们对这种疾病缺乏量化的了解。研究 对FAIS患者的髋关节解剖和生物力学进行了研究，得出了相互矛盾的数据，可能是由于 不准确测量技术的应用。FAI形态的发病率也很高 在无症状人群中(即阳性对照)，这阻碍了理解FAI原因的进展 形态会造成损害。在这里，我们应用实验和计算技术来推进 了解FAIS的病理生理学。我们将研究三个队列：FAIS患者、阴性对照和 积极对照。目标1将测量在倾斜行走、旋转和下蹲时的活体髋关节 使用双重透视的三个队列。我们假设FAIS患者会表现出运动学上的改变； 然而，根据我们的初步数据，我们假设患者的活动范围不会减少。此外，我们 假设与阴性对照相比，阳性对照的运动学发生了改变。在子目标中 1，我们将可视化动态过程中髋关节形状与其运动位置之间的交互作用 使用双荧光透视数据的统计形状建模进行加载。完成目标1改善临床 通过使我们能够可视化动态加载过程中病理形态的影响来理解FAIS。目标 2将对软骨唇部力学进行分析，以提高对FAIS病理生理学的认识。具体来说， 我们将使用经过验证的管道生成骨骼、软骨和唇骨的有限元模型。我们会比较一下 载荷传递到唇部以及骨软骨和软骨唇交界处的剪应力和应变 倾斜行走、旋转和蹲下。我们假设转移到唇骨的负荷增加了，并且 FAIS的软骨剪应力和应变在骨软骨和软骨唇交界处升高 病人。阳性对照组经历的代偿性运动可能会保持软骨唇应力和 菌株在正常范围内。因此，我们假设有限元结果在以下方面没有显著差异 两个对照组。次级目标2将量化髋部形状的局部测量和 软骨唇力学。目标2的完成将增强对骨关节炎患者发病机制的了解 费斯。确定积极的对照如何处理他们的畸形可以为新的治疗策略提供依据。

PROJECT SUMMARY By some estimates, femoroacetabular impingement syndrome (FAIS) accounts for 82% of hip osteoarthritis (OA) cases. FAIS patients present with a loss of sphericity of the femoral head, reduction in femoral-neck offset, and/or an excessively prominent acetabular wall. Patients report pain that is position- or motion-related. Often, cartilage is delaminated from bone and the labrum is torn. The theory of FAIS pathophysiology is that pathoanatomy causes pathomechanics. However, we lack a quantitative understanding of the disease. Studies that have examined hip anatomy and biomechanics in FAIS patients have yielded conflicting data, likely due to the application of inaccurate measurement techniques. There is also a high prevalence of FAI morphology among the asymptomatic population (i.e., positive controls), which has hindered progress to understand why FAI morphology causes damage. Herein, we apply experimental and computational techniques to advance understanding of FAIS pathophysiology. We will examine three cohorts: FAIS patients, negative controls, and positive controls. Aim 1 will measure in-vivo hip articulation during inclined walking, pivoting, and squatting in the three cohorts using dual fluoroscopy. We hypothesize that patients with FAIS will exhibit altered kinematics; however, given our preliminary data, we posit that range of motion will not be reduced in patients. Further, we hypothesize that positive controls will have altered kinematics when compared to negative controls. In Sub-Aim 1, we will visualize the interaction between the shape of the hip joint and its kinematic position during dynamic loading using statistical shape modeling of the dual fluoroscopy data. Completion of Aim 1 improve clinical understanding of FAIS by enabling us to visualize the effects of pathologic shape during dynamic loading. Aim 2 will analyze chondrolabral mechanics in-silico to improve understanding of FAIS pathophysiology. Specifically, we will generate finite element models of bone, cartilage, and labrum using a validated pipeline. We will compare load transfer to the labrum and shear stresses and strains at the osteochondral and chondrolabral junction during inclined walking, pivoting, and squatting. We hypothesize that load transfer to the labrum is increased, and cartilage shear stresses and strains at the osteochondral and chondrolabral junctions are elevated in FAIS patients. Compensatory motion experienced by the positive control group may keep chondrolabral stresses and strains within normal. Thus, we hypothesize that there will be no significant differences in FE results between the two control groups. Sub-Aim 2 will quantify relationships between local measures of hip shape and chondrolabral mechanics. Completion of Aim 2 will enhance understanding of OA pathogenesis in patients with FAIS. Identifying how positive controls cope with their deformities could inform new treatment strategies.