四种方向单腿跳膝关节应力分布特征的有限元分析

关键词：前交叉韧带重建  单腿跳  膝关节  有限元  康复训练

Keywords:anterior cruciate ligament reconstruction  single leg jump  knee joint  finite element method  rehabilitation training

摘要：

      摘要 目的：探讨单腿跳不同方向对膝关节交叉韧带、软骨及半月板应力分布特征的影响。 方法：采集8例受试者进行单腿前跳、单腿内侧跳、单腿外侧跳以及单腿垂直跳的运动学数据和地面反作用力，通过逆动力学计算获取膝关节反力作为边界条件和荷载，并基于膝关节三维有限元模型对单腿跳触地过程进行数值仿真。 结果：不同方向的单腿跳会使双侧半月板的应力分布、股骨软骨接触应力峰值以及前交叉韧带（anterior cruciate ligament， ACL）的接触点拉应力发生较大变化。单腿内侧跳的ACL接触点拉应力峰值在四种跳跃方式中最高（28.46MPa/20.76MPa），而单腿垂直跳最低（19.1MPa/14.02MPa），股骨接触点和胫骨接触点分别相差49.64%和48.07%。此外，单腿垂直跳的股骨软骨接触应力峰值与其他3种情况相比较大，达到9.85MPa。 结论：单腿垂直跳触地过程中ACL接触点拉应力峰值较低，可以作为前交叉韧带术后康复训练的评价指标和训练手段，但在实际运动过程中应注意患者膝关节附近肌群的肌力训练，以及下肢的协调性和稳定性训练，以防止触地过程中软骨和半月板的急性和慢性损伤。

Abstract:

      Abstract Objective：To investigate the influence of different directions of single leg jump on the stress distribution of cruciate ligament， cartilage and meniscus. Method：The kinematics data and ground reaction force of single leg forward jump， single leg inside jump， single leg outside jump and single leg vertical jump were collected from 8 subjects. The knee reaction force was obtained as boundary condition and load through inverse dynamics calculation， and the touchdown process of single leg jump was simulated based on the three-dimensional finite element model of knee joint. Result：The stress distribution of the meniscus， the peak value of the contact stress of the femoral cartilage and the tensile stress of the contact point of anterior cruciate ligament (ACL) would be greatly changed by the jumping of one leg in different directions. The peak value of tensile stress at ACL contact point was the highest (28.46MPa / 20.76MPa) in single leg medial jump and the lowest (19.1MPa / 14.02MPa) in vertical jumping mode， and the differences between femur contact point and tibia contact point were 49.64% and 48.07%， respectively. In addition， the peak value of the contact stress of the femur cartilage of the single leg vertical jump was larger than that of the other three modes， reaching 9.85MPa. Conclusion：The peak value of tensile stress at ACL contact point is low in the process of one leg vertical jumping to the ground， which can be used as an evaluation index and training means for postoperative rehabilitation training of ACL. However， in the actual exercise process， we should pay attention to the muscle strength training around the knee joint and the coordination and stability training of the lower limbs， so as to prevent the acute and chronic injury of cartilage and meniscus in the process of touching the ground.