GOALI: Microstructure and Ultrastructure of Ceramic-substrate and Ceramic-apposed Bone Interfaces in Coated Prosthetic Implants for Joint Arthroplasty

9904046霍布斯本项目是一项小组研究工作，涉及三个机构（马萨诸塞州理工学院、波士顿布里格姆妇女医院和Smith Nephew，Inc.）的研究人员。Orthopaedics Division，孟菲斯，TN），其旨在提高对涂层矫形装置（例如仅在美国每年植入约250，000名患者的髋关节和膝关节置换假体）的过程生物整合以及涂层与假体的底层金属合金的粘附性的基本理解。 诸如磷酸钙化合物羟基磷灰石的涂层促进了骨与这种骨植入物的结合，而故意生长的氧化皮诸如氧化锆在关节部位提供了上级磨损性能。 此类涂层的机械失效可能发生在涂层/骨界面或涂层/合金界面（或涂层本身附近），导致植入物松动或产生刺激性磨损颗粒。 该计划包括两个界面的完整性的调查，在第一种情况下，重点是骨结合到生物活性羟基磷灰石涂层沉积等离子喷涂和离子束辅助沉积方法，主要应用于非骨水泥髋关节置换假体，并在第二个耐磨氧化锆氧化规模的Zr-Nb合金组件的粘附，主要兴趣在全膝关节置换术。 在犬股骨和胫骨中进行3小时至10天的体内（活体）植入和在适当模拟培养液中进行的体外（试管）实验正在进行中，主要的研究工具是高分辨率电子显微镜，提供有关涂层和界面以及涂层表面骨矿化进展的高分辨率结构和化学信息。 在相同的标本上采用标记技术来识别作为骨形成前体的各种蛋白质。这些技术通过X射线测定涂层应力状态和测量涂层表面粗糙度来补充。

9904046HobbsThis program is a group research effort, involving investigators at three institutions (Massachusetts Institute of Technology, Brigham & Women's Hospital, Boston, and Smith & Nephew, Inc. Orthopaedics Division, Memphis, TN), which aims to improve fundamental understanding of the process bio-integration of coated orthopaedic devices, such as hip and knee replacement prostheses which are implanted into some 250,000 patients yearly in the U.S. alone, and the adherence of coatings to the underlying metal alloy of the prosthesis. Coatings such as the calcium phosphate compound hydroxyapatite encourage the bonding of bone to such osteo-implants, while deliberately grown oxidation scales such as zirconium oxide provide superior wear properties in joint locations. Mechanical failure of such coatings can occur at the coating/bone interface or at the coating/alloy interface (or nearby within the coating itself), either loosening the implant or contributing irritating wear particles. The program comprises an investigation of the integrity of both interfaces, in the first case focusing on bone-bonding to bioactive hydroxyapatite coatings deposited by both plasma spraying and ion-beam assisted deposition methods, with primary application to cementless hip-replacement prostheses, and in the second on the adhesion of hard-wearing zirconia oxidation scales to Zr-Nb alloy components, of primary interest in total knee replacements. Both in vivo (live) implantations into dog femurs and tibiae for times between 3 hours to 10 days and in vitro (test tube) experiments in appropriate simulated culture fluid are being pursued.The primary investigative tool is high-resolution electron microscopy, providing high-resolution structural and chemical information about the coatings and interfaces and the progress of bone mineralization at coating surfaces. Labeling techniques are being employed on the same specimens to identify various proteins which serve as precursors to bone formation These techniques are being supplemented by X-ray determinations of coating stress states and measurement of coating surface roughnesses.