Local head roughening as a factor contributing to variability of total hip wear: A finite element analysis
Local head roughening as a factor contributing to variability of total hip wear: A finite element analysis
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DOI：
10.1115/1.1517275
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发表时间：
2002-12-01
影响因子：
1.7
通讯作者：
Callaghan, JJ
中科院分区：
文献类型：
--
作者：
Brown, TD;Stewart, KJ;Callaghan, JJ
患者之间在磨损率和磨损方向上的巨大变异性一直是全髋关节置换术(THA)队列中普遍存在的特征。由于处于磨损频谱高端的患者特别担心骨质溶解和松动，因此了解为什么一些人的磨损速度远远超过他们的平均水平是很重要的。已建立的聚乙烯磨损计算模型被用来检验这样的假设，即在其他因素相同的情况下，局部股骨头粗化区域的临床典型变异性可以解释临床观察到的磨损量和磨损方向的大部分变异性。该模型实现了Archard磨粒/粘着磨损关系，该关系包含了接触应力、滑动距离和(隐含的)轴承表面摩擦学。进行了系统的试验，以探讨头部粗化程度、粗化区大小和粗化区位置的影响。结果表明，在假设的磨损系数高度下，回收试件的典型头部粗化变异性(保守)导致磨损方向约30度变化，体积磨损率约7倍变化。由于这些数据表明，抓头的随机性可以解释磨损方向和磨损率的其他难以解释的变化，第三体碎片可能是导致THA人群中最有问题的子集过度磨损的关键因素。
Large inter-patient variability in wear rate and wear direction have been a ubiquitous attribute of total hip arthroplasty (THA) cohorts. Since patients at the high end of the wear spectrum are of particular concern for osteolysis and loosening, it is important to understand why some individuals experience wear at a rate far in excess of their cohort average. An established computational model of polyethylene wear was used to test the hypothesis that, other factors being equal, clinically typical variability in regions of localized femoral head roughening could account for much of the variability observed clinically in both wear magnitude and wear direction. The model implemented the Archard abrasive/adhesive wear relationship, which incorporates contact stress, sliding distance and (implicitly) bearing surface tribology. Systematic trials were conducted to explore the influences of head roughening severity, roughened area size, and roughened area location. The results showed that, given the postulated wear factor elevations, head roughening variability (conservatively) typical of retrieval specimens led to approximately a 30degrees variation in wear direction, and approximately a 7-fold variation in volumetric wear rate. Since these data show that randomness in head scratching can account for otherwise-difficult-to-explain variations in wear direction and wear rate, third-body debris may be a key factor causing excessive wear in the most problematic subset of the THA population.