压配型假体柄部-股骨界面匹配和优化设计

ANATOMY FIT AND OPTIMIZED DESIGN OF THE INTERFACE BETWEEN PRESS-FIT HIP AND BONE

目的探讨有效提高假体-骨结合面的匹配度,加强假体初始固定强度,并使假体外形更为优化的方法。方法通过计算机图形、图像等手段对成人股骨髓腔截面形态进行自动提取,并采用圆锥曲线拟合、二次曲线简化、形心曲线拟合等数学方法,将股骨髓腔截面形态简化为长短径、形心轴线等几个参数来设计假体。应用计算机辅助设计(com pu ter-a ided des ign,CAD)等方法对骨的结构和髋假体进行分析和评估。采用“peg-in-ho le”的方法通过“拔出”模拟优化假体外形。结果CAD分析显示假体与股骨平均匹配度为23.2%,骨损伤率0.033%。插入分析程序对所有测试样例的拔出路径的获得均有效,且拔除时能直观定量测量最大交叠面积。结论提供了一套从图像处理到图形设计及其设计优化的方法,在假体设计开发中具有较强的应用价值。

Objective To improve the fitness and initial fixation strength between the hip and bone and to optimize the shape of the prosthetic implants. Methods The cross section of hip canal was automalically extracted by Image processing. By using taper curve fit,hypo-curve predigesting and the curve of shape center fit, the parameters of long-short diameter and the curve of shape center were got to design the hip shape. CAD was adopted to analyze and evaluate the configuration of bone and shape of hip. The “peg-in-hole” was employed to optimize the shape of implant by the visual test of “Drawing out” in computer. Results 23. 2% hip bone average matching rate and 0. 033% bone damage rate were presented by CAD analysis. The implant extraction path were validated visually and quantitatively by measuring the maximum amount of overlap in the path configuration. Conclusion The valuable method for prothsetic hip design was presented by the way of image processing,graphics design and optimizing design in this study.