ACL移植物初始力对胫股关节接触性能影响

为深入研究ACL重建中移植物初始力对术后膝关节性能的影响,该文从MRI数据中提取膝关节各组织来构造出正常膝关节三维模型,通过对正常膝关节添加隧道与植入ACL移植物构建出ACL单束/双束重建膝关节模型。随后在压扭、压弯及压扭弯载荷作用下通过对ACL移植物施加10N~100N范围内的初始力进行有限元仿真,以此来分析初始力对关节软骨、半月板、移植物的应力分布影响以及对关节间接触力和关节位移的影响,所得结论如下:首先,单束/双束重建胫股关节的软骨、半月板的应力分布受初始力影响较小,其最大等效应力随初始力的变化分别不超过25%和20%,但移植物上的最大应力却随初始力的增加明显增大;其次,单束重建关节中半月板传递的轴向载荷随初始力增大而增加,双束重建关节中半月板传递载荷则随着初始力的增大反而减小;最后,在初始力10N~100N范围内,胫骨前移与所承受的前向力载荷之间基本成线性关系,前移量随初始力增大而减小。根据重建关节特性曲线表明,初始力对双束重建的影响稍微小于单束重建。

EFFECT OF THE INITIAL FORCE OF GRAFTS ON THE CONTACT CHARACTERISTIC OF TIBIO-FEMORAL JOINT AFTER ACL RECONSTRUCTION

To further evaluate the effect of the initial force of grafts on the characteristic of a knee after ACL reconstruction,the normal model of a tibio-femoral joint was firstly constructed from the tissues extracted from the MRI data of a knee.Then the single-bundle and double-bundle ACL reconstruction models of the joint were derived by introducing the tunnel and graft to the normal model.The experiments were carried on by applying 3 kinds of loads(compression-torsion load,compression-bending load and compression-torsion-bending load) ranged from 10N to 100N to the graft to analyze the effect of the initial force on the stress distribution of cartilages,meniscus and grafts,contact forces between joint tissues and the displacements of the joint.The results show that: 1) the effect of the initial forces on the stress distribution of the cartilages and meniscus after the single-bundle or double-bundle ACL reconstruction is not significant,the maximum stress changing is less than 25% and 20% respectively,but the maximum stress on the graft will increase dramatically as the initial force increases;2) In the single-bundle model,the axial load transferred by meniscus will increase as initial force increases,but in the double-bundle it will decrease;3) When the initial force increases from 10N to 100N,the anterior displacement of the tibia changes linearly as the anterior force changes,and the anterior displacement decreases as the initial force increases.According to characteristic curves of the reconstruction modals,the effect of the initial force on a double-bundle model is less than that on a single-bundle one.