预期条件下不同侧切角度膝关节应力状态的有限元分析

Finite Element Analysis on Stress State of Knee Joint with Different Lateral Cutting Angles under Expected Conditions

目的探讨预期条件下不同角度侧切触地过程中膝关节运动学、地面反作用力(ground reaction force,GRF)特征以及软骨、半月板的应力状态。方法采集14名受试者在预期条件下分别进行45°、90°和135°侧切时的运动学和GRF数据,通过Visual 3D逆动力学计算获取膝关节反作用力,基于膝关节三维有限元模型分别对3种侧切角度下触地过程进行数值仿真。结果预期条件下3种侧切角度在触地过程中的膝关节运动学特征存在显著性差异(P<0.001),膝关节屈曲程度随侧切角增大而增加;垂直GRF随侧切角增加而显著减小(P<0.001),水平GRF呈现出相反的趋势;3种侧切角度下,90°侧切时髌骨软骨以及股骨软骨接触应力峰值较大,前交叉韧带(anterior cruciate ligament,ACL)接触点主应力峰值较大,其次为135°和45°侧切;3种侧切角度下,外侧股骨软骨接触应力峰值均大于内侧。结论 90°侧切运动时膝关节损伤风险更大,135°侧切时膝关节内部的应力状态与90°侧切相比较为良好。预期条件下膝关节损伤风险并不随侧切角增大而升高。

Objective To investigate the characteristics of knee kinematics and ground reaction force( GRF),as well as the stress state of cartilage and meniscus in the process of lateral incisions at different cutting angles under expected conditions. Methods Kinematics and GRF data of 14 subjects at 45°,90° and 135° cutting angle respectively under expected conditions were collected. The knee joint reaction force was obtained through the inverse dynamics calculation of Visual 3D. Based on three-dimensional( 3D) finite element model of the knee joint,the contact process at 3 lateral cutting angles was simulated. Results Under expected conditions,there were significant differences in knee joint kinematics characteristics at 3 cutting angles during contact process( P<0. 001),and the knee flexion increased with the cutting angle increasing;the vertical GRF decreased significantly with the cutting angle increasing( P< 0. 001),while the horizontal GRF showed the opposite trend;for 3 cutting angles,the peak contact stress of patellar cartilage and femoral cartilage was larger at 90° cutting angle,the peak principal stress at anterior cruciate ligament( ACL) contact point was also larger at 90° cutting angle,and the following was at 135° and 45° cutting angle,respectively;the peak contact stress of lateral femoral cartilage was larger than that of medial femoral cartilage at 3 cutting angles. Conclusions The risk of knee joint injury is higher at90° cutting angle,and the stress state of knee joint at 135° cutting angles is better than that at 90° cutting angle,and the risk of knee joint injury does not increase with the increase of cutting angle under expected conditions.