首页|人工髋关节超高分子量聚乙烯高边衬垫的接触力学和边缘负载

人工髋关节超高分子量聚乙烯高边衬垫的接触力学和边缘负载

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全髋关节置换术后衬垫边缘出现边缘负载不仅会增加脱位风险,而且会加剧假体的摩擦磨损.发生边缘负载与假体的安装位置、几何设计及患者运动状态等高度相关.该文基于金属-聚乙烯接触副建立了髋关节高边衬垫在步态载荷下的接触力学和边缘负载的有限元分析模型.该模型考虑了日常生活中正常行走、上楼梯、下楼梯和深蹲4种步态及20种相对极端的臼杯安装位置,以研究高边衬垫的接触应力、边缘负载和等效塑性应变情况.结果表明:衬垫的等效塑性应变、发生塑性变形的体积、边缘负载和边缘负载的持续时间都随臼杯外展角和前倾角增加而增加;相比于另外3种步态,深蹲步态更容易使衬垫产生塑性形变,对衬垫造成的破坏最大;在臼杯外展角不低于50°的情况下,将高边衬垫的高边放置于人体后上方不但能避免出现边缘负载,还能显著降低衬垫的塑性应变.
Contact mechanics and edge loading of UHMWPE elevated-rim liner for artificial hip joints
[Objective]After total hip arthroplasty,the contact stress spot between the femoral head and the liner can easily move from the liner's inner surface to its contour edge under different gaits,resulting in edge loading(EL)at the liner edge.The occurrence of EL will reduce the mechanical properties of the liner,increase the wear of the hip prostheses,and reduce the service life of hip prostheses and the quality of life of patients.EL is related to the prosthetic mounting position,geometric design,and patient motion status.This study aimed to investigate the contact mechanics and EL of elevated-rim liner edges at different gaits and mounting positions to guide clinical prosthesis mounting and postoperative rehabilitation of patients.[Methods]In this study,we developed a finite element analysis model of elevated-rim liner contact mechanics and hip joint EL under gait loading based on a metal-on-polyethylene contact bearing.Four gaits(normal walking,ascending stairs,descending stairs,and deep squatting)common to the patient's daily life were used as kinetic inputs to the finite element model.The model considered the radiographic inclination and anteversion of the acetabular cup at relatively extreme positions and the elevated rim of the liner at different orientations in human body.After finite element mesh sensitivity analyses,mechanical results such as contact stresses,EL,EL duration,equivalent plastic strain,and volume of the equivalent plastic strain of the elevated-rim liner were investigated.[Results]The finite element results showed that the maximum surface normal contact stresses on the inner surface of the elevated-rim liner under normal walking,ascending stairs,descending stairs,and deep squatting gaits were 11.60,12.44,11.96,and 12.07 MPa,respectively,with no significant difference.The maximum surface contact stresses on the liner where EL occured were 3.29,3.40,4.85,and 4.45 MPa,respectively.The ratios of the EL duration to the gait cycle were 14%,34%,50%,and 54%,respectively.The maximum equivalent plastic strains were 2.82 × 10-4,4.89 × 10-4,5.31 × 10-4,and 6.56 × 10-4,respectively,and the volumes where the equivalent plastic strains occurred were 37.07,65.01,67.66,and 150.00 mm3,respectively.[Conclusions]The equivalent plastic strain of the elevated-rim liner,the volume in which plastic deformation occurs,and the EL of the elevated-rim liner and its duration all increase with the radiographic inclination and anteversion of the acetabular cup.Compared with the other three gaits,the deep squatting gait is more likely to cause plastic deformation of the liner and consequently the most damage to the liner.Therefore,patients should avoid movements with high flexion after total hip arthroplasty.Placing the elevated rim of the liner on the posterosuperior side of the body and the radiographic inclination of the acetabular cup no less than 50° can avoid EL and significantly reduce the plastic strain of the liner.Total hip arthroplasty should consider not only the patient's postoperative impingement-free range of motion but also the mechanical condition of the patient's postoperative prostheses,thus prolonging the life of the prostheses.

contact mechanicsartifical hip jointedge loadingultra-high molecular weight polyethyleneelevated-rim liner

冯涛、张小刚、张国贤、谢庆云、张亚丽、靳忠民

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西南交通大学 机械工程学院,摩擦学研究所,成都 610031

中国人民解放军西部战区总医院,成都 610083

接触力学 人工髋关节 边缘负载 超高分子量聚乙烯 高边衬垫

国家自然科学基金中央高校基本科研业务费专项四川省自然科学基金

520350122682023ZTPY0522022NSFSC1940

2024

清华大学学报(自然科学版)
清华大学

清华大学学报(自然科学版)

CSTPCD北大核心
影响因子:0.586
ISSN:1000-0054
年,卷(期):2024.64(3)
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