A Multi-Scale Modeling Construct of Knee Mechanics following ACL Reconstruction

描述（由申请人提供）：前交叉韧带（ACL）重建手术通常能成功改善关节稳定性，但患者发生早发性骨关节炎（OA）的风险很高。目前尚不清楚为什么OA会在这些患者中发展，或者如何最好地计划治疗策略来降低OA的风险。这是一个非常具有挑战性的问题，因为前瞻性研究需要大量的受试者数量和多年的时间来破译。目前的生物力学计算模型不适合解决这个问题，因为它们分离了宏观（全身）和微观（组织力学）尺度上的行为。因此，一种新的多尺度计算结构正在形成，以检查步态中肌肉骨骼动力学和软组织力学之间存在的固有耦合。该结构用于深入了解ACL重建后可能影响软骨接触应力的关键手术因素，这些因素被认为是关节骨关节炎改变的前提。本研究的三个目的是：1)评估ACL移植物刚度、预张力和隧道结构对术中膝关节松弛度评估的影响；2)研究手术因素和肌肉力对动态MRI测量的体内膝关节力学的耦合影响；3)研究人体运动过程中重建膝关节的多尺度生物力学行为。这些目的是为了验证关节软骨接触应力大小和位置随活动肌肉负荷显著变化的假设，并且对用于重建前交叉韧带的隧道的位置和方向高度敏感。这些研究的结果对于告知临床方法以最好地降低韧带损伤和手术修复后OA的风险具有重要意义。

DESCRIPTION (provided by applicant): Anterior cruciate ligament (ACL) reconstructive surgeries are often successful at improving joint stability, but patients have a highly elevated rik for developing early onset osteoarthritis (OA). It is not well understood why OA develops in these patients, or how one can best plan a treatment strategy to mitigate the risk for OA. This is a very challenging question to answer empirically, since prospective studies require large subject numbers and many years to decipher. Current computational models in biomechanics are ill-suited to solve this problem because they decouple behavior that occurs at the macro (whole body) and micro (tissue mechanics) scales. Hence, a new multi-scale computational construct is being formulated to examine the inherent coupling that exists between musculoskeletal dynamics and soft tissue mechanics during gait. This construct is used to gain insights into the key surgical factors that can affect cartilage contact stresses after ACL reconstruction, which are believed to predicate osteoarthritic changes to the joint. The three aims of the study are to: 1) Assess effects of ACL graft stiffness, pre-tension and tunnel architecture on intra-operative assessments of knee laxity, 2) Investigate the coupled influence of surgical factors and muscle forces on in vivo knee mechanics as measured using dynamic MRI, 3) Investigate the multi-scale biomechanical behavior of reconstructed knees during human locomotion. These aims are used to test the hypothesis that articular cartilage contact stress magnitudes and location vary significantly with active muscle loading, and are also highly sensitive to the position and orientation of the tunnels used to reconstruct the ACL. The results of these studies are important for informing clinical approaches that can best mitigate the risk fo OA following ligament injury and surgical repair.