股骨柄假体的二维生物力学评价与优化选择(英文)

Two-dimensional biomechanics evaluation and the optimal selection of a femoral stem prosthesis

背景:人工髋关节置换术前选择假体时,不仅要考虑在几何学上达到与患者股骨髓腔的匹配,而且还要在生物力学性能上达到最优,这对提高全髋关节置换术后疗效,具有较现实的意义。目的:对4组与股骨匹配的股骨柄假体进行生物力学的评价,寻找与正常股骨力学分布最为接近的股骨柄假体。设计:对比观察。单位:同济大学附属东方医院骨科、解放军第二军医大学长海医院骨科、上海交通大学机械与动力工程学院。材料:实验于2004-12/2005-10在上海交通大学机械与动力工程学院生命质量与机械工程实验室完成。选用无髋部疾患、股骨近端形态正常志愿者(男性,40岁,身高175cm,体质量78kg)的股骨拍摄标准正位X射线片,并以DICOM格式存入存贮器中。志愿者签署知情同意书,同时报医学伦理委员会审批。模板:Ⅰ号假体:Zimmer versys Fiber Metal Taper11#;Ⅱ号假体:Plus APL 2#;Ⅲ号假体:Welink Ribbed system cementless01#;Ⅳ号假体:Lima F2L 1#。方法:在Matlab中导入股骨近端X射线正位片及4组股骨-股骨柄假体模板的bmp格式的图像文件,分别提取股骨、带假体模板的股骨二维轮廓数据,利用ANSYS软件建立股骨、股骨-股骨柄几何模型及二维非线性有限元模型,负荷加载后对股骨近端的应力分布进行分析、比较。主要观察指标:股骨近端的应力分布。结果:Ⅰ,Ⅳ号假体对所研究的股骨而言其应力大小及分布与正常股骨相近,但两者相比Ⅰ号更为接近,应为最佳选择。结论:通过基于X射线片与模板的股骨柄假体二维生物力学的分析比较,可对股骨柄假体的生物力学性能作出评价,为假体的优化选择提供依据。

BACKGROUND： Prosthesis selection for total hip replacement is determined by geometrical matching with femoral medullary cavity of patients and the optimal biodynamics. It is of great significance for elevating outcomes of total hip replacement. OBJECTIVE： To evaluate the biomechanics of four groups of femoral stem prostheses matched with a femur and to get a stem whose mechanics distribution is similar to the normal femur. DESIGN： Controlled observation. SETTING： Department of Orthopaedics of Oriental Hospital Affiliated to Tongji University, Department of Orthopaedics of Changhai Hospital of Second Military Medical University of Chinese PLA, and Department of Mechanical and Power Engineering of Shanghai Jiao Tong University. MATERIALS： Experiments were performed at the Laboratory of Life Quality and Machinery Engineering of Department of Mechanical and Power Engineering of Shanghai Jiao Tong University from December 2004 to October 2005. A male volunteer aged 40 years with the normal proximal femur （175 cm height and 78 kg weight）, free from hip disease, were selected. X-ray image of the eutopic femur was shot and wrote into memory in the format of DICOM. The volunteer signed an informed consent. The experiment was approved by Hospital Ethical Committee. No. Ⅰ prosthesis, Zimmer versys Fiber Metal Taper1 1#, No. Ⅱ prosthesis, Plus APL 2#, No. Ⅲprosthesis, Welink Ribbed system cementless01#, and No. Ⅳprosthesis, Lima F2L 1# were used in this study. METHODS： The ezDICOM software was used to read files with DICOM format of femoral X-ray image, which was converted into files with bmp format. The image files with bmp format of the proximal femur X ray were introduced with Matlab software after regulation, and the two-dimensional contour data of femur were extracted. Prosthesis matched with the template was set in PhotoShop 7.0 software. The two-dimensional contour data of prosthetic femur were extracted in MATLAB software. The ANSYS software was used to establish the model of geometrical and two-dimensional nonlinearity finite element including femur and femur-femoral stem. Stress distribution in the proximal femur was analyzed and compared by loading. MAIN OUTCOME MEASURES： Stress distribution of the proximal femur. RESULTS： Stress value and distribution of No. Ⅰ prosthesis and No. Ⅳprosthesis in proximal femur were similar to the normal femur. Moreover, No. Ⅰ prosthesis was better than No. Ⅳprosthesis. CONCLUSION： The biomechanics of femoral stem prostheses has been evaluated by analyzing and comparing the two-dimensional biomechanics of the femoral stem prostheses based on X-ray and template, which can offer support in optimal prosthesis selection.