Effects of anterior cruciate ligament reconstruction on the association between quadriceps muscle dynamics, knee joint biomechanics, and articular cartilage loading during walking

项目摘要 前交叉韧带重建（ACLr）患者行走时膝关节峰值小于典型峰值 在体重接受阶段，伸肌力矩（pKEM）和膝关节屈曲偏移减少 走路这些自愿四头肌激活的缺陷被认为是生物力学级联的关键 ACLr患者创伤后骨关节炎（PTOA）的潜在高发病率。它有 有人认为，膝关节步态生物力学的变化可以将关节接触力转移到区域， 不适应负荷，特别是当事件允许软骨适应的时间很少时。步态 在ACLr患者中观察到的变化可能是由虚弱和中枢抑制的组合引起的 在功能活动期间，必须采用新的康复策略，因为股四头肌 单独加强似乎不能使步态生物力学恢复到未受伤的值。这将是第一个研究 建立股四头肌运动学之间的机械联系，自愿力量产生的缺陷， ACLr患者适应不良的软骨负荷模式。这项研究将使用多尺度 方法与步态生物反馈的新应用，在体内超声成像，和尖端的膝关节 仿真。通过我们的试点体内超声测试，我们观察到一个根本不同的行为， ACLr和未受伤对照组之间的股四头肌激活。肌束长度变化的差异可能 可能是与膝关节负荷改变相关的股四头肌功能障碍的功能后果。拟议研究 基于这一概念，在需要不同功能的任务期间评估股四头肌收缩动力学， 需要从战略上评估调节ACLr患者pKEM的效果。而且 拟议的研究将评估股四头肌激活和膝关节生物力学的系统性变化 通过生物反馈或步行速度提示影响软骨接触力。这项研究将立即 对我们理解股四头肌激活缺陷在PTOA发展中的作用的影响 在ACLR之后。

PROJECT SUMMARY Individuals with anterior cruciate ligament reconstruction (ACLr) walk with smaller than typical peak knee extensor moments (pKEM) and diminished knee flexion excursion during the weight acceptance phase of walking. These deficits in voluntary quadriceps activation are considered critical in the biomechanical cascade underlying disproportionally high rates of post-traumatic osteoarthritis (PTOA) in individuals with ACLr. It has been suggested that changes in gait biomechanics at the knee joint can shift articular contact forces to regions not conditioned to loading, particularly when the event allows little time for cartilage adaptation. The gait changes observed in individuals with ACLr likely result from a combination of weakness and central inhibition during functional activities and must be addressed with a novel rehabilitation strategy because quadriceps strengthening alone appears unable to return gait biomechanics to uninjured values. This will be the first study to establish mechanistic links between quadriceps kinematics, deficits in voluntary force production, and maladaptive cartilage loading patterns in individuals with ACLr. The proposed research will use a multi-scale approach with novel applications of gait biofeedback, in vivo ultrasound imaging, and cutting-edge knee joint simulations. Through our pilot in vivo ultrasound testing, we observe a fundamentally different behavior in quadriceps activation between ACLr and uninjured controls. Differences in muscle fascicle length change may be a functional consequence of quadriceps dysfunction relevant to altered knee loading. The proposed research builds upon this concept to evaluate quadriceps contractile dynamics during tasks requiring different functional demands to strategically assess the effects of modulating pKEM in individuals with ACLr. Furthermore, the proposed research will evaluate how systematic changes in quadriceps activation and knee joint biomechanics cued via biofeedback or walking speed affect cartilage contact forces. The proposed research will have immediate impact on our understanding of the contributions of quadriceps activation deficits in PTOA development following ACLr.