Knee joint mechanics assessments

膝关节前交叉韧带（ACL）完整性的丧失也会改变关节的稳定性和动力学，导致骨关节炎（OA）的风险和发病率增加。然而，关节结构中关节接触力学的直接无创体内量化一直受到限制。因此，正常健康的关节力学特征和导致病理状况的特征并没有很好地确定。研究的总体目标是了解关节力学、关节健康状况、关节损伤和修复机制之间的关系，以及与韧带损伤和修复相关的退行性变化的发展。将检验三个主要假设：（H1）通过体内膝关节刚度测量和ACL松弛预测来检测ACL完整性和关节组织状况的差异，（H2）软骨力变形（FD）特征与蛋白聚糖（PG）浓度相关，使用集成MRI和关节加载技术，（H3）异常动态关节稳定性与体内关节刚度，软骨FD特征和PG浓度的变化相关。在不同的膝关节屈曲和负荷条件下，对健康组、先天性关节松弛组、前交叉韧带缺陷伴早期退行性改变组和前交叉韧带缺陷伴严重OA组4组的膝关节松弛和软骨受力变形特征进行成像和量化。利用新的关节松弛装置、磁共振成像、图像配准技术和建模，将开发关节和前交叉韧带松弛组织特征的规范范围。使用创新的成像技术和加载设备，评估体内软骨变形特征并将其与软骨组成（蛋白多糖浓度）相关联。将使用3D运动分析评估每组的关节动态稳定性，并与组织特征相关。本研究为联合表征工具包奠定了基础，并为临床治疗评估提供了独特而新颖的进展，具有潜在的影响。

The loss of integrity of the anterior cruciate ligament (ACL) in the knee can also alter joint stability and dynamics and lead to higher risk and incidence of osteoarthritis (OA). However, direct non-invasive in-vivo quantification of joint contact mechanics within the joint structures has been limited. Consequently, characteristics of normal healthy joint mechanics, and those leading to pathological conditions are not well established. The overall research goals are to understand relations amongst joint mechanics, joint health status, joint injury and repair mechanisms, and the development of degenerative changes associated with ligament injury and repair. Three main hypotheses will be tested: (H1) Differences in ACL integrity and joint tissue condition are detected with in-vivo knee joint stiffness measures and ACL laxity predictions, (H2) Cartilage force-deformation (FD) characteristics are correlated to proteoglycan (PG) concentrations using integrated MRI and joint loading techniques, and (H3) Abnormal dynamic joint stability is correlated with alterations in vivo joint stiffness, cartilage FD characteristics and PG concentrations. Knee joint laxity, and cartilage force-deformation characteristics will be imaged and quantified for 4 in-vivo groups: healthy, congenital joint laxity, ACL deficient with early degenerative changes and ACL deficient with severe OA, under various knee flexion and loading conditions. Using novel joint laxity device, MR imaging, image registration techniques, and modeling, normative ranges for joint and ACL laxity tissue characteristics will be developed. In-vivo cartilage deformation characteristics will be evaluated and correlated with cartilage composition (proteoglycan concentration) using innovative imaging techniques and loading devices. Joint dynamic stability will be assessed for each group using 3D motion analysis, and correlated to tissue characteristics. This research develops the foundations for a joint characterization toolkit, and provides a unique and novel advance with potential impact for clinical treatment evaluations.