Brown Thomas D, Elkins Jacob M, Pedersen Douglas R, Callaghan John J
Department of Orthopaedics and Rehabilitation University of Iowa, Iowa City, IA ; Department of Biomedical Engineering University of Iowa, Iowa City, IA.
Department of Orthopaedics and Rehabilitation University of Iowa, Iowa City, IA ; Department of Biomedical Engineering University of Iowa, Iowa City, IA ; Iowa City Veterans Administration Medical Center Iowa City, IA.
Iowa Orthop J. 2014;34:1-15.
In contemporary total hip arthroplasty, instability has been a complication in approximately 2% to 5% of primary surgeries and 5% to 10% of revisions. Due to the reduction in the incidence of wear-induced osteolysis that has been achieved over the last decade, instability now stands as the single most common reason for revision surgery. Moreover, even without frank dislocation, impingement and subluxation are implicated in a set of new concerns arising with advanced bearings, associated with the relatively unforgiving nature of many of those designs. Against that backdrop, the biomechanical factors responsible for impingement, subluxation, and dislocation remain under-investigated relative to their burden of morbidity. This manuscript outlines a 15-year program of laboratory and clinical research undertaken to improve the scientific basis for understanding total hip impingement and dislocation. The broad theme has been to systematically evaluate the role of surgical factors, implant design factors, and patient factors in predisposing total hip constructs to impinge, sublux, and/or dislocate. Because this class of adverse biomechanical events had not lent itself well to study with existing approaches, it was necessary to develop (and validate) a series of new research methodologies, relying heavily on advanced finite element formulations. Specific areas of focus have included identifying the biomechanical challenges posed by dislocation-prone patient activities, quantifying design parameter effects and component surgical positioning effects for conventional metal-on-polyethylene implant constructs, and the impingement/dislocation behavior of non-conventional constructs, quantifying the stabilizing role of the hip capsule (and of surgical repairs of capsule defects), and systematically studying impingement and edge loading of hard-on-hard bearings, fracture of ceramic liners, confounding effects of patient obesity, and subluxation-mediated worsening of third body particle challenge.
在当代全髋关节置换术中，不稳定是约2%至5%的初次手术及5%至10%的翻修手术中的一种并发症。由于过去十年磨损诱导性骨溶解发生率的降低，不稳定现已成为翻修手术最常见的单一原因。此外，即使没有明显脱位，撞击和半脱位也与先进轴承引发的一系列新问题相关，这与许多此类设计相对苛刻的特性有关。在此背景下，相对于其发病负担，导致撞击、半脱位和脱位的生物力学因素仍研究不足。本手稿概述了一项为期15年的实验室和临床研究计划，旨在改善理解全髋关节撞击和脱位的科学基础。总体主题是系统评估手术因素、植入物设计因素和患者因素在使全髋关节结构易于发生撞击、半脱位和/或脱位方面的作用。由于这类不良生物力学事件不太适合用现有方法进行研究，因此有必要开发（并验证）一系列新的研究方法，这在很大程度上依赖于先进的有限元公式。具体关注领域包括确定易脱位患者活动所带来的生物力学挑战，量化传统金属对聚乙烯植入物结构的设计参数效应和部件手术定位效应，以及非传统结构的撞击/脱位行为，量化髋关节囊（以及囊缺损手术修复）的稳定作用，系统研究硬对硬轴承的撞击和边缘载荷、陶瓷衬垫的骨折、患者肥胖的混杂效应以及半脱位介导的第三体颗粒挑战恶化情况。
