【摘要】 目的研究膝关节假体形面轮廓对假体关节面间接触应力的影响。方法基于MRI(magnetic resonance imaging)图像采集建立多角度正常膝关节模型。依据自然膝关节的解剖结构,从中提取出个体膝的结构尺寸及形面特征,设计出渐变形面的膝关节假体,按照全膝关节置换手术的规范流程建立植入渐变形面假体后的全膝三维模型,并通过有限元分析,比较植入假体后对股骨/胫骨关节面等效应力的影响。结果植入渐变形面的假体膝在屈曲角度0°~60°时对于髁面的应力分布影响不大,但大于60°,尤其是80°时,应力分布变化明显;另外,对内/外侧髁面的最大等效应力有较大的改变。结论在膝关节假体的设计建模中,尽量重现人体关节构造,益于保证置换后整个膝关节的协调运作。整个设计过程及方法对于完善和改进假体的设计具有重要的参考意义。更多还原

【Abstract】 Objective To investigate the influence of articular surfaces of the total knee replacements on the contact stress of the replacements. Methods Based on the magnetic resonance imaging( MRI) scanning pictures from a volunteer,the three-dimensional models of the healthy human knee joint at different flexion angles were constructed. According to the anatomy structure of the natural knee,the geometrical and individual data were extracted from the normal articular surfaces. Then,the total knee replacements with gradually-changed surfaces were constructed. Based on the standardized process of total knee arthroplasty,the three-dimensional models containing implants were constructed. The finite element simulation was conducted to analyze the impact of implants on the equivalent stress distribution. Results The results showed that the newly-designed replacements had little impact on the stress distribution during 0° ~ 60°,but had marked influence at large flexion angle,especially at 80°. Maximum equivalent stress of both medial and lateral condyles changed significantly. Conclusion In the process of knee replacements design,the normal knee articular surfaces contact should be better restored to achieve better coordination operation of the whole knee joint. The whole design process provides reference for the design and improvement of the total knee replacement.更多还原