Effect of Age, Sex, and Injury on Regional Stresses and Resulting Growth of the Anterior Cruciate Ligament

项目总结 近年来，儿童前十字韧带(ACL)损伤和手术治疗率迅速上升 好几年了。尤其令人担忧的是，儿科患者比成人患者更有可能经历大约五倍的 手术重建后继发性前交叉韧带损伤。此外，性别在伤害发生率中扮演着一个因素，女性 在青春期，前交叉韧带损伤的风险比男性高，但在童年或成年期没有。然而， 前交叉韧带损伤的机制以及这些年龄和性别差异背后的原因尚不清楚。 这在一定程度上是由于在受伤期间难以通过实验观察前交叉韧带，以及关于 前交叉韧带及其前内侧(AM)和后外侧(PL)束在整个骨骼生长过程中的功能。ACL 当韧带承受较高的局部应力--力量集中在一小块区域--时，可能会发生损伤。 我们小组的初步数据显示，AM和PL束的生长和功能依赖于性别，所以它 性别和年龄似乎会影响前交叉韧带内局部应力的大小和位置。因此， 这项建议的目的是确定年龄和性别如何影响整个前交叉韧带的局部应力 骨骼生长和部分前交叉韧带损伤如何影响前交叉韧带剩余部分的生长和重塑 以及膝关节中的其他组织。目标1将评估性别和年龄如何影响年内经历的地区压力 在外加载荷作用下，前交叉韧带的AM和PL束。目标2将评估区域压力如何在 局部损伤的即时影响。目标3将评估组织和膝关节力学的长期变化 前交叉韧带部分损伤后，会影响前交叉韧带剩余部分及周围软骨的生长和改建。 这些目标将通过开发经过实验验证的特定于对象的有限元模型来实现 不同骨骼发育阶段男性和女性前交叉韧带的机械负荷。此外，长久以来- 部分前交叉韧带损伤的长期影响将在活体内使用猪模型进行研究。增长和重塑将 使用定量成像技术和生长的计算模拟进行非侵入性研究 对局部组织应力的反应。

PROJECT SUMMARY Pediatric anterior cruciate ligament (ACL) injuries and surgical intervention rates are rapidly increasing in recent years. Of particular concern, pediatric patients are approximately five times more likely than adults to experience a secondary ACL injury after surgical reconstruction. Further, sex plays a factor in injury rates, where females experience a higher risk of ACL injury than males during adolescence, but not childhood or adulthood. However, the mechanism of ACL injuries and the reasons behind these age and sex-related differences remain unclear. This is, in part, due to difficulty experimentally observing the ACL during injury and limited data regarding the function of the ACL and its anteromedial (AM) and posterolateral (PL) bundles throughout skeletal growth. ACL injuries likely occur when the ligament experiences high local stresses—forces concentrated over a small area. Preliminary data from our group has shown sex-dependent growth and function of the AM and PL bundles, so it seems likely that sex and age will impact the magnitude and location of local stresses within the ACL. Therefore, the objective of this proposal is to determine how age and sex impact local stresses in the ACL throughout skeletal growth and how partial ACL injury may affect growth and remodeling of the remaining portion of ACL and other tissues in the knee joint. Aim 1 will assess how sex and age impact regional stresses experienced in the AM and PL bundles of the ACL under applied loads. Aim 2 will assess how regional stresses change as an immediate effect of partial injury. Aim 3 will assess how long-term changes in tissue and knee joint mechanics after partial ACL injury impact growth and remodeling of the remainder of the ACL and surrounding cartilage. These aims will be accomplished by developing experimentally validated subject-specific FE models to simulate mechanical loading of the ACL in males and females at different stages of skeletal growth. Additionally, the long- term impact of partial ACL injury will be investigated in vivo using the porcine model. Growth and remodeling will be studied non-invasively using quantitative imaging techniques and computational simulations of growth in response to regional tissue stresses.