Mechanics and Performance of Traceable UHMWPE Implants

描述(申请人提供)：全髋关节置换术(THR)是治疗晚期退行性关节疾病的标准手术。然而，13%-18%的THR手术是再手术，与初次THR相比，结果更差，经济负担更大。在过去的十年中，轴承技术在配方和部件设计方面发生了重大变化，推出了第一代高度交联型超高分子量聚乙烯材料(重熔和退火)，以及最近推出的第二代材料，通过顺序退火或维生素E扩散稳定下来。随着这些更耐磨的材料的出现，磁头的尺寸已经增加，以减少不稳定的发生率。十年前，我们开始了一项多机构可追踪回收收集，以确定聚乙烯组件的活体变化，并分析假体周围组织对聚乙烯磨损碎片的反应。我们已经开发了通过分析假体周围组织样本来测量回收的植入物的机械性能、氧化和体积磨损，以及聚乙烯磨损碎片的大小和形状以及相关的免疫学反应的方案。我们现在有证据表明，伽马惰性灭菌、退火和重熔的聚乙烯在体内的降解发生在短期到中期的植入时间(&lt；10年)。仍然需要了解高交联度聚乙烯体内降解的长期影响，并评估新材料和设计改进的性能。通过外植体研究，我们将评估：回火和重熔轴承植入5年以上的性能；第二代高交联度衬垫的临床性能；以及头部大小、磨损和轮缘损坏之间的关系。我们假设：在植入后的五年内，以体内氧化、磨损和松动为修订原因的第一代和第二代高交联衬垫将没有区别；第二代聚乙烯配方将保持氧化稳定性和类似于重熔的高交联衬垫的机械性能；并且股骨头尺寸大于28 mm不会增加第一代和第二代交联衬垫的轴承表面磨损和轮缘损坏。通过更好地了解轴承技术因素和聚乙烯部件的生存能力，实现建议的目标将提高THR的临床性能。 与公共健康相关：轴承技术在过去十年中在配方和部件设计方面经历了重大变化，引入了第一代和第二代高度交联的UHMWPE材料。我们设备回收研究的一个基本目标是了解成功的植入材料和设计，并通过外植体、组织和临床分析评估失败。因此，拟议研究的成功完成将提供有关THR植入物性能和临床结果的基本信息，这是知情的医疗保健决策所必需的。

DESCRIPTION (provided by applicant): Total hip replacement (THR) surgery is the standard of care for advanced degenerative joint disease. However, 13-18% of all THR surgeries are reoperations, which have poorer outcomes and greater economic burden than primary THRs. Bearing technologies have undergone major changes with respect to formulation and component design over the past decade with the introduction of first-generation highly crosslinked ultra-high molecular weight polyethylene materials (remelted and annealed) and the recent introduction of second-generation materials, stabilized with sequential annealing or vitamin-E diffusion. With the advent of these more wear resistant materials, head sizes have increased to reduce the incidence of instability. Ten years ago, we began a multi-institution traceable retrieval collection to determine in vivo changes to polyethylene components and to analyze periprosthetic tissue responses to polyethylene wear debris. We have developed protocols to measure the mechanical properties, oxidation, and volumetric wear of retrieved implants, as well as the size and shape of polyethylene wear debris and the associated immunologic response through analysis of periprosthetic tissue samples. We now have evidence to show that degradation of gamma inert-sterilized, annealed, and remelted polyethylene occurs in the body for short- to intermediate-term implantation times (<10 years). There is a continued need to understand the long-term effects of in vivo degradation of highly crosslinked polyethylenes and to evaluate the performance of new material and design modifications. Through explant studies we will evaluate: the performance of retrieved annealed and remelted bearings implanted greater than 5 years; the clinical performance of second-generation highly crosslinked liners; and relationships between head size, wear, and rim damage. We hypothesize that: beyond five years of implantation, in vivo oxidation, wear and loosening as reasons for revision of annealed and remelted highly crosslinked liners will not differ; 2nd-generation polyethylene formulations will preserve oxidative stability and mechanical properties comparable to remelted highly crosslinked liners; and femoral head sizes greater than 28 mm will not increase bearing surface wear and rim damage in first and second generation crosslinked liners. Achieving the proposed aims will lead to improved clinical performance of THRs through a better understanding of bearing technology factors and survivorship of polyethylene components. PUBLIC HEALTH RELEVANCE: Bearing technologies have undergone major changes with respect to formulation and component design over the past decade with the introduction of first- and second- generation highly crosslinked UHMWPE materials. A fundamental objective of our device retrieval research is to understand successful implant materials and designs and assess failures through explant, tissue and clinical analysis. Thus, successful achievement of the proposed research will provide essential information on THR implant performance and clinical outcomes, which are needed for informed health care decisions.