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

9904046目标本项目是一个团队研究项目，涉及三个机构(麻省理工学院、波士顿布里格姆妇女医院和田纳西州孟菲斯的Smith&Amp；Nephew，Inc.骨科)的研究人员，旨在提高对涂层矫形设备的生物集成过程的基本了解，例如仅在美国每年就会植入约250,000名患者的髋关节和膝关节置换假体，以及涂层与假体底层金属合金的附着力。涂层，如磷酸钙化合物羟基磷灰石，促进了骨与这种骨植入物的结合，而故意生长的氧化膜，如氧化锆，在关节位置提供了优异的磨损性能。这种涂层的机械失效可能发生在涂层/骨界面或涂层/合金界面(或涂层本身内部的附近)，松动植入物或造成刺激性磨损颗粒。该计划包括对两种界面的完整性的调查，第一种情况侧重于通过等离子喷涂和离子束辅助沉积方法沉积的生物活性羟基磷灰石涂层的骨结合，主要应用于非骨水泥髋关节置换假体，第二种情况是关于耐磨氧化锆氧化片与全膝关节置换主要关注的锆Nb合金成分的粘附性。体内(活体)植入狗股骨和胫骨的时间为3小时至10天，以及在适当的模拟培养液中进行体外(试管)实验。主要的研究工具是高分辨率电子显微镜，提供关于涂层和界面的高分辨率结构和化学信息以及涂层表面骨矿化的进展。在相同的标本上使用了标记技术来识别作为骨形成前体的各种蛋白质，这些技术还得到了涂层应力状态的X射线测定和涂层表面粗糙度的测量。

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.