Polyurethane Load Bearing Surfaces for Total Hip Joint Replacement

描述（由申请人提供）：随着越来越多的年轻患者进行全髋关节置换术（THA），需要能够承受更高患者活动和加载周期次数的THA植入物。在大多数常见的THA植入物中使用的超高分子量聚乙烯易受高磨损率的影响，产生数十亿亚微米磨损颗粒，与骨溶解介导的植入物失败有关。本研究的目的是用专门为这种承重应用开发的聚氨酯（PUR）弹性体取代THA植入物的超高分子量聚乙烯成分。PUR弹性体是专门开发的，具有比超高分子量聚乙烯更高的韧性，硬度和模量，这将导致更低的变形，附着力和磨损。PUR弹性体也明显比超高分子量聚乙烯更亲水，这应该转化为THA植入物关节表面之间更有效的“流膜”润滑，降低摩擦，最终降低磨损。在第一阶段，我们建议在生理髋关节模拟器中比较选定的PUR弹性体和超高分子量聚乙烯的磨损率，以证明PUR弹性体在减少THA植入物表面磨损率和亚微米磨损颗粒形成方面的潜力。此外，将完成一项研究，比较选定的PUR弹性体和超高分子量聚乙烯的氧化介导降解，这是体内聚合物降解的主要原因，会导致磨损率大幅增加。在第二阶段，将选择具有最佳耐磨性能和抗氧化性能的PUR弹性体进行进一步的优化和评估。第一阶段确定的磨损性能相关性和抗氧化成分相关性将作为第二阶段进一步优化材料的基础。拟议的商业应用：由于预期较低的磨损率和降低骨溶解的可能性，使用PUR弹性体衬垫的THA植入物有望占据THA植入物市场的很大一部分，美国的THA数量超过27万，全球超过150万。在全髋关节置换术中的成功应用有望导致PUR弹性体作为全膝关节和肩部植入物以及其他关节置换物的承载表面的使用。公共卫生相关性：该项目的总体目标是为全髋关节置换术植入物开发新的承重聚氨酯表面。新的承重聚氨酯表面将提高替代植入物的耐用性和使用寿命，显著降低失败的风险。这项研究中开发的技术有可能改善每年接受髋关节置换手术的150多万新患者的生活。

DESCRIPTION (provided by applicant): As total hip arthroplasty (THA) is being performed on increasingly younger patients, there is a need for THA implants that can sustain higher patient activity and number of loading cycle. UHMW-PE used in most common THA implants have been shown susceptible to high rates of wear, generating billions of sub-micron wear particles associated with the osteolysis-mediated implant failures. The objective of this study is to replace the UHMW-PE components of THA implants with polyurethane (PUR) elastomers specifically developed for this load-bearing application. The PUR elastomers were specifically developed with higher toughness, hardness, and modulus than the UHMW-PE, which should lead to lower deformation, adhesion, and abrasion. PUR elastomers are also significantly more hydrophilic than the UHMW-PEs, which should translate into more effective "fluid-film" lubrication between the articulating surfaces of THA implants, lower friction and ultimately lower wear. In Phase I we propose to compare the wear rates of selected PUR elastomers and UHMW-PE in a physiological hip joint simulator to demonstrate the potential of PUR elastomers to reduce the surface wear rates in THA implants and formation of sub-micron wear particles. Additionally, a study will be completed to compare the oxidation-mediate degradation of selected PUR elastomers and UHMW-PE, which is the primary cause for in vivo polymer degradation that can lead to considerable wear rate increases. PUR elastomer with the best combination of wear characteristics and resistance to oxidation will be selected for further optimization and evaluation in Phase II. Wear-property correlations and oxidation resistance-composition correlations determined in Phase I will be used as bases for further material optimization in Phase II. PROPOSED COMMERCIAL APPLICATIONS: With the expected lower wear rates and reduced potential for osteolysis, THA implants with PUR elastomer liners are expected to capture a significant portion of the THA implant market, which numbers over 270,000 THAs in the US and over 1.5 million world-wide. Successful application in THA is expected to lead to use of PUR elastomers as load bearing surfaces in total knee and shoulder implants and other joint replacements. PUBLIC HEALTH RELEVANCE: The overall goal of this project is to develop new load-bearing polyurethane surfaces for total hip replacement implants. The new load-bearing polyurethane surfaces will improve the durability and life- span of the replacement implants, significantly reducing the risk of failure. The technology developed in this study has the potential to improve lives of over 1.5 million new patients who each year undergo hip replacement surgeries.