全膝关节置换后肌肉强度衰减对关节接触力的影响

Effect of Different Level of Strength Loss for Quadriceps and Hamstrings on Tibiofemoral Contact Forces After Total Knee Replacement

利用开源软件nmsBuilder和OpenSim构建的全膝关节置换后的个性化多体动力学模型,研究了正常步态下,股四头肌和腘绳肌不同程度的肌肉强度衰减对胫股关节接触力的影响。通过调整目标肌肉的最大等长力以实现肌肉强度衰减,然后对模型先后执行逆向运动学、静态优化和关节接触力分析。肌肉强度衰减分3种情况:股四头肌和腘绳肌的八块肌肉整体强度依次衰减10%,20%,30%,40%;股四头肌肌群和腘绳肌肌群分别衰减50%和100%;八块肌肉强度分别衰减100%.结果表明:对肌肉进行整体强度衰减会减小胫股关节接触力;适当对股四头肌肌群和腘绳肌肌群进行强度衰减可使胫股关节接触力增大;除了股直肌,其他单个肌肉强度衰减都会使内侧胫股关节接触力的峰值变大且直接影响膝关节假体的使用寿命。肌肉强度衰减引起内侧胫股关节接触力峰值变大可能会对膝关节造成二次损伤;在多体动力学骨肌建模中,肌肉强度衰减有利于提高关节接触力和肌肉力的预测精度。

On the basis of the subject-specific musculoskeletal multi-body dynamics model after total knee replacement established by two open-source software nmsBuilder and OpenSim,we studied the effect of different level of strength loss for quadriceps and hamstrings on tibiofemoral contact forces under normal gait pattern.This study adjusted the maximum isometric force of the target muscle to achieve the purpose of muscle strength loss,then inverse kinematics,static optimization and joint reaction force analysis were performed in order.Muscle strength loss in three ways:muscle of quadriceps group and hamstrings group all reduced by 10%,20%,30%,40%sequentially,quadriceps group and hamstrings group reduced by 50%and 100%respectively and eight muscles of quadriceps group and hamstrings group reduced strength by 100%sequentially.Strength loss for all muscle reduced tibiofemoral contact forces.Appropriate strength loss for quadriceps group and hamstring group increased tibiofemoral contact forces.In addition to the rectus femoris,the strength loss for the individual muscles increased peak value of medial contact force,which affected the life of the knee prosthesis directly.Muscle strength loss resulted in a higher peak value for medial contact force,which may cause secondary injury to the tibiofemoral joint.In the process of multi-body dynamics modeling,the loss of muscle strength is beneficial to improving the prediction accuracy of joint contact force and muscle force.