三翼髋臼假体有限元模型的建立及其力学分析

摘要

Objective To analyze and evaluate a new acetabular revision component with three wings. Methods The finite-element models of a new acetabular component and acetabulum with bone loss were established to calculate the interface stresses during a normal gait cycle with use of the finite-element formulations. Results The finite-element analysis demonstrated that stress and strain at the interfaces of bone-shell and metal-polyethylene liner had the same direction of change but no remarkable difference between them. In the study, the result indicated increased contact stresses with an increased joint load and orientation. The peak stress was tested at the second stage of gait cycle. The stress of wings increased gradually from rim to root. Its peak stress that was significantly lower than yield force of the Co-Cr alloy was at the joint between the wing and the shell. The stress of graft had the same change rule as the joint force. The part of graft near to acetabular component was subjected to higher stress conditions. Conclusion The hip forces can transfer from acetabular component and implant to acetabulum. The result of the finite-element analysis underlined the importance of wings of the new acetabular component. The wing can help to improve the antitorsion ability of acetabular component and to minimize its aseptic loosening rate. Therefore, based on results of this study and clinical application, the acetabular component with wings is known a viable means for acetabular revision in the presence of bone loss. But further research is needed as to this acetabular component.%目的 对于一种临床上用于髋臼骨缺损的新型三翼髋臼翻修假体的设计进行有限元分析及力学评价.方法 建立三翼翻修假体及缺损髋臼的有限元模型,应用有限元分析公式计算在髋臼骨缺损翻修后,翻修假体在正常步态周期内的应力变化规律.结果 研究证实在正常步态周期内,三翼髋臼假体金属壳两侧界面的应力变化规律相同,并且两者的各种应力值之间的差异无统计学意义(P＞0.05).假体所受的最大应力取决于经髋关节作用力的大小和作用方向,在正常步态周期中,其最大值在第二期.假体翼部应力的分布规律均是由翼的边缘向翼根部逐渐增大,至翼根与球壳连接处为最大,但是远小于钴铬钼合金材料的屈服强度.移植材料所受的应力值随着各期经髋关节作用力的大小而变化,移植填充材料在临近假体的部分所受应力较大.结论 研究表明外界作用力经股骨头和三翼假体传导到髋臼骨,在上部则经过移植物到达髂骨,其中三翼结构在对抗扭转剪力方面起主要作用,有助于减少假体的松动率.因此,通过上述研究结合其临床应用结果 ,可以认为三翼翻修假体对于巨大髋臼骨缺损不失为一项有益的选择.