个体化股骨假体的计算机辅助设计实践及模拟力学实验

背景:由于人体的绝对个性化特点,标准人工假体与患者骨骼之间的误差使二者难以很好匹配,不能确保人工关节的长期稳定.目的:利用已开发的计算机辅助设计和制造程序,建立个体化股骨假体的三维模型.并通过模拟对比力学实验.验证个体化股骨假体是否优于普通型股骨假体.设计、时间及地点:开放性实验.于2006-09/2007-05在吉林大学第一临床医院骨科研究所和吉林大学生物力学研究所完成.材料:成人新鲜股骨尸体骨.方法:取成人尸体股骨做全长CT扫描,得到CT二维图像.将其输入计算机.利用开发的边缘识别和三维轮廓提取软件对二维图像进行处理,识别髓腔内外轮廓,提取髓腔内外轮廓及假体轮廓数据,建立股骨和个体化股骨假体的三维模型.利用SolidWorks软件建立普通生物犁和骨水泥犁假体三维模型,在此平台上模拟Il缶床手术置换骨水泥型、生物型和个体化定制型3类股骨假体.主要观察指标:分别模拟单足和双足站立状态,测量3种股骨假体的应力分布、界面应力和初始微动情况.结果:对最初设计的软件中边缘提取算法进行了改进,采用Canny算子,得到了更好的边缘检测结果.改进后的软件运行稳定,计算结果町信,符合预期要求.设计的个体化股骨假体的假体应力、股骨上应力、界面应力及初始微动均显著低于生物型和骨水泥型股骨假体(P＜0.01).结论:开发的计算机辅助设计程序运行准确可靠,可完成假体的计算机辅助设计,在此平台上设计的个体化股骨假体具有优于普通股骨假体的生物力学特性.

Computer-aided design and simulated-mechanical study of custom-made femoral prosthesis

BACKGROUND:Standard artificial prosthesis does not well match to patients' skeleton due to absolute individuation,while the difference between them does not keep the stabilization of artificial joint for a long term.OBJECTIVE:To construct three-dimensional models of custom-made femoral prosthesis by using computer-aided design and to verify whether custom-made femoral prosthesis is superior to popular femoral prosthesis via simulating and contrasting mechanical study.DESIGN,TIME AND SETTING:Opening study was performed in the Orthopaedics Institute of the First Clinical Hospital and the Biomechanics Institute,Jilin University between September 2006 and May 2007.MATERIALS:One fresh femur was derived from adult corps.METHODS:Two-dimensional images of the fresh femur was obtained by using total-length CT scanning and processed with computer edge recognition and three-dimensional contour extraction software to identify outer and inner contour of bone cavity,extract contour data of bone cavity and prosthesis,and construct three-dimensional models of femur and custom-rhade femoral prosthesis.SolidWorks software was used to establish three-dimensional prosthetic models in common biological and bone cement types; moreover,bone-cement,biological,and custom-made femoral prosthesis were replaced via simulating clinical surgery.MAIN OUTCOME MEASURES:Standing on single or double feet was simulated to measure stress distribution,interface stress,and primary micromotion of femoral prosthesis in the three types.RESULTS:Edge extracting was replaced by Canny calculator,characterizing by stable running,credible outcome,and consistent with the primary request.Stress,femoral stress,interface stress,and primary micromotion of custom-made femoral prosthesis were significantly lower than biological and'bone-cement femoral prosthesis (P ＜ 0.01).CONCLUSION:The computer-aided design is reliable to perform the assistant design of prosthesis; furthermore,biomechanical properties of the custom-made femoral prosthesis are superior to those of popular femoral prosthesis.