Nonidentical and outlier duty cycles as factors accelerating UHMWPE wear in THA: A finite element exploration
Nonidentical and outlier duty cycles as factors accelerating UHMWPE wear in THA: A finite element exploration
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DOI：
10.1002/jor.20265
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发表时间：
2007-01-01
影响因子：
2.8
通讯作者：
Brown, Thomas D.
中科院分区：
文献类型：
--
作者：
Lundberg, Hannah J.;Stewart, Kristofer J.;Brown, Thomas D.
在全髋关节置换术(THA)患者队列中，磨损率和磨损方向差异很大。第三，身体效应和患者活动水平的广泛差异被认为是导致穿戴变化的两个因素。滑动距离耦合接触有限元公式被用来检验不同的占空比(不同的活动或第三身体挑战的改变)在聚乙烯磨损中产生加速的假设。研究了不同的占空比、时变的股骨头粗糙化和异常步态输入的影响。在没有股骨头粗化的情况下，联合行走/爬楼梯磨损模拟不会导致比仅行走模拟明显更高的体积磨损，但当包括粗化区时，行走/爬楼梯磨损体积比类似粗糙的仅行走模拟增加约57%。为了研究随时间变化的股骨头粗化，通过在股骨头上的一个位置进行股骨头粗化，并在模拟中途切换到另一个位置来开始磨损模拟。结果根据粗化位置的不同而不同，但磨损大幅增加的情况是在改变头部粗化位置后不久磨损率瞬间跃升。通过增加或减少联合接触力和运动输入范围来模拟异常值占空比，以达到正常受试者群体的97.5和2.5%的水平。由此产生的磨损表现出与每个输入(力或运动范围)改变的百分比成正比的增加或减少。(C)2006年骨科研究会。由威利期刊出版公司出版。
Wear rate and wear direction vary considerably within total hip arthroplasty (THA) patient cohorts. Third body effects and wide-ranging differences in patient activity levels are two factors suspected of contributing to wear variability. A sliding-distance-coupled contact finite element formulation was used to test the hypothesis that nonidentical duty cycles (differing activities, or change of third body challenge) produce accelerations in polyethylene wear. Effects of nonidentical duty cycles, time-variant femoral head roughening, and outlier gait inputs were investigated. Without femoral head roughening, combination walk/stair-climb wear simulations did not result in appreciably higher volumetric wear than a walk-only simulation, but when a roughened zone was included, walk/stair-climb volumetric wear increased by approximately 57% above that of a similarly roughened walk-only simulation. To investigate time-variant femoral head roughening, wear simulations were begun with femoral head roughening at one location on the femoral head, switching to another location halfway through the simulation. Results varied depending on roughening sites, but cases of substantial increase in wear involved a transient jump in wear rate shortly after the change of head roughening location. Outlier duty cycles were simulated by increasing or decreasing the joint contact force and range of motion inputs, to levels at the 97.5th and 2.5th percentiles of a population of normal subjects. The resulting wear showed an increase or decrease closely proportional to the percentage by which each input (force or range of motion) was changed. (c) 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.