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Kinematic analysis of artificial knee implants using markers embedded in a bone

使用嵌入骨骼中的标记对人工膝关节植入物进行运动分析

基本信息

批准号：
10680789
负责人：
ISHIDA Akimasa
金额：
$ 2.05万
依托单位：
Tokyo Medical and Dental University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

1. Pose estimation of the knee implantTo assess the accuracy of the proposed method, we carried on the in vitro experiments as follows. The tibial component was fixed on a plastic block which was used as a substitute of a bone and four markers were embedded in the plastic block. Radiographs of the component were taken with the frame that comprised of eight calibration markers. Then we determined the local coordinates of markers in the tibial coordinate system. The rms value of errors was O.1 8mm. Once the local coordinates of markers are known. it is possible to estimate pose of the component using information of projected coordinates of markers. The resultant error of rotation and in-plane translation were 0.2° and 0.2 mm, respectively.2. Motion analysis of the mobile bearing knee implantTo assess the motion of an insert of the mobile bearing knee implant, in vitro experiments were carried on as follows. Markers were embedded in an insert and a radiograph was taken. Then motion of an insert was measured using information of projected coordinates of markers, and the error was 0.2 mm. In order to examine the mechanism of the mobile bearing and fixed bearing knee implants, the 3D model of the knee were constructed and simulation study was carried on. During the knee flexion of the fixed bearing knee implant, contact points between a femoral component and an insert moved backward at first, but moved forward slightly. On the other hand, in the case of the mobile bearing knee implant, contact points moved backward monotonically with knee flexion, which resembled natural knee motion.

1.膝关节植入物的位姿估计为了评估所提出的方法的准确性，我们进行了如下的体外实验。将胫骨部件固定在塑料块上，塑料块用作骨替代物，并将四个标记物嵌入塑料块中。使用由8个校准标记组成的框架拍摄组件的X线照片。然后确定标记在胫骨坐标系中的局部坐标。误差的均方根值为0.18mm。一旦知道标记的局部坐标。可以使用标记的投影坐标的信息来估计部件的姿态。旋转误差为0.2°，面内平移误差为0.2mm.移动的支撑膝关节植入物的运动分析为了评估移动的支撑膝关节植入物的插入物的运动，进行如下体外实验。将标记嵌入衬垫中，并拍摄X线片。为了研究移动的和固定平台膝关节植入物的作用机理，建立了膝关节的三维模型并进行了仿真研究，固定平台膝关节植入物在膝关节屈曲过程中，股骨部件与衬垫之间的接触点首先向后移动，但稍微向前移动了一点。另一方面，对于移动的支承膝关节植入物，接触点随着膝关节屈曲单调向后移动，这类似于自然的膝关节运动。