|关键词||肘关节 外固定 旋转中心定位 圆度 共面性|
|其他题名||A new kinematics method of determining elbow external fixator rotation axis and evaluation of its feasibility|
结果 每位志愿者5条运动轴线与其平均运动转轴之间的距离偏差均小于3mm，角度偏差均小于5°；两种定轴方法确定的6例肘关节模型旋转轴的入点偏差平均为1.6972 mm，出点偏差平均为1.8383 mm，角度偏差平均为1.3217° 。偏差均很小，在临床实际操作的可接受范围之内；尸体标本克氏针植入后的透视影像显示植入结果可以满足临床需求。
Objective To study a new positioning method of elbow external fixation rotation axis, the kinematic data of elbow joint in flexion are measured by optical positioning system. And visualized display and analysis of the kinematic data are carried out. Also, the feasibility of the method is evaluated.
Methods Four normal adult volunteers, six Sawbone elbow models and three elbows of two cadavers are brought into this experiment. The kinematic data of five elbow flexion are collected respectively by optical positioning system. The rotation axes of elbow joints are fitted by least square method. The kinematic data and fitting results are visually displayed. According to the fitting results, the average moving planes and rotation axes are calculated. Thus, the rotation axes of new kinematic methods are got. By using standard clinical methods, the entrance and exit points of rotation axes of six Sawbone elbow models are located under X-ray. And The Kirschner wires are placed as the representatives of rotation axes using traditional positioning methods. Then, the entrance point deviation, the exit point deviation and the angle deviation of two kinds of located rotation axes are compared. The Kirschner wires are implanted into the three elbows of two cadavers, and verified its accuracy under X-ray.
Result As to four volunteers, the indicators represented circular degree and coplanarity of elbow flexion movement trajectory of each volunteer are both about 1mm. All the distance deviations of the moving axes to the average moving rotation axes of five volunteers are less than 3 mm. All the angle deviations of the moving axes to the average moving rotation axes of five volunteers are less than 5°. As to six Sawbone models, the average entrance point deviations, the average exit point deviations and the average angle deviations of two different rotation axes determined by two kinds of located methods are respectively 1.6972 mm, 1.8383 mm and 1.3217°. All the deviations are very small. They are all in an acceptable range of clinical practice. As to the three elbows of two cadavers, X-ray images after implantation of Kirschner wires show that implantation results can meet the clinical needs.
Conclusion The values represented circular degree and coplanarity of volunteer’s elbow single curvature movement trajectory are very small. The result shows that the elbow single curvature movement can be regarded as the approximate fixed axis movement. The new method can make up the deficiency of the traditional fixed axis method. It can replace the traditional method in accuracy.
|韩巍. 肘关节外固定架旋转轴的运动学定位方法及可行性评估[D]. 北京大学第四临床医学院. 北京大学,2016.|
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