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

项目总结 前十字韧带重建术(ACLR)患者行走时的膝关节峰值小于典型峰值 伸肌力矩(PKEM)和减少的膝关节屈曲漂移在体重接受阶段 走路。这些股四头肌自主激活的缺陷被认为是生物力学级联反应的关键。 ACLR患者创伤后骨关节炎(PTOA)的潜在高发病率。它有 已经提出，膝关节步态生物力学的改变可以将关节接触力转移到区域 不适应负荷，特别是当比赛几乎没有时间让软骨适应的时候。步态 在ACLR患者中观察到的变化可能是虚弱和中枢抑制相结合的结果 在功能活动期间，必须用新的康复策略来解决，因为股四头肌 单靠加强似乎无法将步态生物力学恢复到未受伤的水平。这将是第一次研究 建立股四头肌运动学、自愿力生产缺陷和 ACLR患者中的不适应软骨负荷模式。拟议的研究将使用多个标度 步态生物反馈、体内超声成像和尖端膝关节的新应用 模拟。通过我们的体内超声试验，我们观察到了一种根本不同的行为 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 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。拟议的研究 建立在这个概念的基础上，在需要不同功能的任务中评估股四头肌收缩动力学 要求从战略上评估调制pKEM对ACLR患者的影响。此外， 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 通过生物反馈或行走速度发出的提示会影响软骨接触力。拟议的研究将立即 影响我们理解股四头肌激活缺陷在PTOA发育中的作用 跟随ACLR。

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.