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

这个项目是一个小组研究项目，涉及三个机构（麻省理工学院、波士顿布莱根妇女医院和史密斯侄儿公司）的研究人员。该项目旨在提高人们对涂层骨科设备生物整合过程的基本理解，例如仅在美国每年就有25万名患者植入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粘附性。像磷酸钙化合物羟基磷灰石这样的涂层促进骨与骨植入物的结合，而故意生长的氧化鳞片，如氧化锆，在关节部位提供了优越的磨损性能。这种涂层的机械故障可能发生在涂层/骨界面或涂层/合金界面（或涂层本身附近），要么使种植体松动，要么产生刺激性磨损颗粒。该项目包括对两种界面的完整性进行调查，第一个案例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，主要应用于无水泥髋关节置换假体，第二个案例侧重于耐磨氧化锆氧化层与Zr-Nb合金成分的粘附，主要应用于全膝关节置换术。目前正在进行体内（活体）植入犬股骨和胫骨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，提供有关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标记技术来识别作为骨形成前体的各种蛋白质。这些技术正在通过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.