Marieswaran M, Jain Ishita, Garg Bhavuk, Sharma Vijay, Kalyanasundaram Dinesh
Centre for Biomedical Engineering, Indian Institute of Technology Delhi, New Delhi, India.
Department of Bioengineering, Indian Institute of Technology Kanpur, Kanpur, India.
Appl Bionics Biomech. 2018 May 13;2018:4657824. doi: 10.1155/2018/4657824. eCollection 2018.
The anterior cruciate ligament is one of the six ligaments in the human knee joint that provides stability during articulations. It is relatively prone to acute and chronic injuries as compared to other ligaments. Repair and self-healing of an injured anterior cruciate ligament are time-consuming processes. For personnel resuming an active sports life, surgical repair or replacement is essential. Untreated anterior cruciate ligament tear results frequently in osteoarthritis. Therefore, understanding of the biomechanics of injury and properties of the native ligament is crucial. An abridged summary of the prominent literature with a focus on key topics on kinematics and kinetics of the knee joint and various loads acting on the anterior cruciate ligament as a function of flexion angle is presented here with an emphasis on the gaps. Briefly, we also review mechanical characterization composition and anatomy of the anterior cruciate ligament as well as graft materials used for replacement/reconstruction surgeries. The key conclusions of this review are as follows: (a) the highest shear forces on the anterior cruciate ligament occur during hyperextension/low flexion angles of the knee joint; (b) the characterization of the anterior cruciate ligament at variable strain rates is critical to model a viscoelastic behavior; however, studies on human anterior cruciate ligament on variable strain rates are yet to be reported; (c) a significant disparity on maximum stress/strain pattern of the anterior cruciate ligament was observed in the earlier works; (d) nearly all synthetic grafts have been recalled from the market; and (e) bridge-enhanced repair developed by Murray is a promising technique for anterior cruciate ligament reconstruction, currently in clinical trials. It is important to note that full extension of the knee is not feasible in the case of most animals and hence the loading pattern of human ACL is different from animal models. Many of the published reviews on the ACL focus largely on animal ACL than human ACL. Further, this review article summarizes the issues with autografts and synthetic grafts used so far. Autografts (patellar tendon and hamstring tendon) remains the gold standard as nearly all synthetic grafts introduced for clinical use have been withdrawn from the market. The mechanical strength during the ligamentization of autografts is also highlighted in this work.
前交叉韧带是人体膝关节六条韧带之一，在关节活动时提供稳定性。与其他韧带相比，它相对更容易发生急性和慢性损伤。受伤的前交叉韧带的修复和自我愈合是耗时的过程。对于恢复积极运动生活的人员来说，手术修复或置换至关重要。未经治疗的前交叉韧带撕裂经常会导致骨关节炎。因此，了解损伤的生物力学和天然韧带的特性至关重要。本文简要总结了突出的文献，重点关注膝关节的运动学和动力学关键主题以及作为屈曲角度函数作用于前交叉韧带的各种载荷，并强调了差距。简要地说，我们还回顾了前交叉韧带的力学特性、组成和解剖结构以及用于置换/重建手术的移植材料。本综述的主要结论如下：（a）膝关节过伸/低屈曲角度时，前交叉韧带上的剪切力最高；（b）在前交叉韧带在可变应变率下的特性对于模拟粘弹性行为至关重要；然而，关于人体前交叉韧带在可变应变率下的研究尚未见报道；（c）在早期研究中观察到前交叉韧带最大应力/应变模式存在显著差异；（d）几乎所有合成移植物已从市场上召回；（e）Murray开发的桥接增强修复是一种有前途的前交叉韧带重建技术，目前正在进行临床试验。需要注意的是，对于大多数动物来说，膝关节完全伸展是不可行的，因此人类前交叉韧带的加载模式与动物模型不同。许多已发表的关于前交叉韧带的综述主要关注动物前交叉韧带而非人类前交叉韧带。此外，本文综述总结了迄今为止使用的自体移植物和合成移植物的问题。自体移植物（髌腱和腘绳肌腱）仍然是金标准，因为几乎所有引入临床使用的合成移植物都已从市场上撤回。本文还强调了自体移植物韧带化过程中的机械强度。
