【摘要】 目的:探讨人工髋关节置换后在不同步速时股骨的力学行为,为髋关节置换患者及医生提供参考性意见。方法:利用人体动力学软件LifeMOD进行步速为0.51、0.61、0.77 m/s的步态仿真,选取行走时全足放平、站立中相、加速推离、摆动中相4个步态事件获得各瞬间髋关节的承力条件,同时建立完整的髋关节置换三维有限元模型,将动力学软件得出的力学条件作为边界条件进行加载,分析置换后股骨的应力分布及其随步速变化的情况。结果:在不同步速的各步态事件下,置换后股骨的整体应力模式并未改变,均由股骨近端到远端逐渐增加,在股骨中下段达到最大,最大应力在前外侧和后内侧附近。在全足放平和加速推离时,股骨应力与步速呈正比,全足放平的应力最大值范围为13.6～17.9 MPa,区间相差4.3 MPa;加速推离的应力最大值范围为3.3～17.6 MPa,应力呈倍数增长。在站立中相和摆动中相时,股骨应力随步速变化略有波动,但是变化程度很小。结论:步速改变对站立支撑时的股骨应力影响不大,但对双腿摆动时的股骨应力有明显影响,特别是在加速推离阶段,股骨应力随着步速增加呈倍数增长,建议患者在髋关节置换术后尽量减慢步行速度。更多还原

【Abstract】 Objective To investigate the mechanical behavior of the femur at different gait speeds after artificial hip replacement and to provide references for hip replacement patients and doctors. Methods The gait simulation was carried out using the human kinetics software LifeMOD with step speeds of 0.51, 0.61 and 0.77 m/s. Four gait events were selected: full foot release during walking, standing phase, accelerated push-off and swinging phase to obtain the stress-bearing conditions of the hip joint at each instant, while a complete three-dimensional finite element model of the hip joint replacement was established, and the mechanical conditions derived from the kinetics software were used as the boundary conditions to analyze the stress distribution in the femur after replacement and its variation with the gait speed. Results The overall stress pattern of the femur did not change after replacement at each gait event at different gait speeds. The stress gradually increased from proximal to distal femur and reached a maximum near the anterolateral and posterior medial regions at the middle and lower femur. During the full foot release and accelerated push-off, femoral stresses were directly proportional to step speed;during the full foot release the maximum stresses ranged from 13.6 to 17.9 MPa with the interval difference being4.3 MPa; during the accelerated push-off the maximum stresses ranged from 3.3 to 17.6 MPa and the stress showed multiplicative increase. During the standing and swinging phases, femoral stresses fluctuated slightly with step speed.Conclusion The change of walking speeds has little effect on the femoral stress during standing support, while affects significantly the femoral stress when the legs swing. Especially in the accelerated pushing off phase the femoral stress shows multiplicative increase with the increase of walking speed. It is suggested that patients should slow down the walking speeds as much as possible after hip replacement.[Chinese Medical Equipment Journal,2021,42(2):6-11]更多还原