目的：利用光学定位系统测量肘关节在屈曲、旋转活动时的运动学数据并进行可视化显示和分析，探索新的肘关节外固定旋转轴的定位方法，并对其可行性进行评估。 方法：利用光学定位系统，分别采集4位正常成年志愿者和6例Sawbone肘关节模型进行五次肘关节屈曲活动时的运动学数据，利用最小二乘法拟合肘关节旋转轴线，对运动学数据和拟合结果进行可视化显示并计算得到平均运动平面和平均运动转轴，从而确定旋转轴；应用标准临床方法对6例Sawbone肘关节模型透视下定位旋转轴的出、入点，并置入克氏针标记代表旋转轴，比较两种方法定位旋转轴的入点、出点及角度偏差。 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3 mm，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1.697 2 mm，出点偏差平均为1.838 3 mm，角度偏差平均为1.321 7° ，偏差均很小，在临床实际操作的可接受范围之内。 结论：肘关节单次屈曲运动轨迹的圆度及共面性良好，可以把肘关节的屈曲伸直活动视为近似固定轴线的运动;该新定轴方法在准确性上可以替代传统方法，并弥补传统定轴方法的不足。

Objective：To study a new positioning method of elbow external fixation rotation axis, and to evaluate its feasibility. Methods: Four normal adult volunteers and six Sawbone elbow models were brought into this experiment. The kinematic data of five elbow flexion were collected respectively by optical positioning system. The rotation axes of the elbow joints were fitted by the least square method. The kinematic data and fitting results were visually displayed. According to the fitting results, the average moving planes and rotation axes were calculated. Thus, the rotation axes of new kinematic methods were obtained. By using standard clinical methods, the entrance and exit points of rotation axes of six Sawbone elbow models were located under X-ray. And The kirschner wires were 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 were compared. Results: As to the four volunteers, the indicators represented circular degree and coplanarity of elbow flexion movement tra-jectory of each volunteer were both about 1 mm. All the distance deviations of the moving axes to the ave-rage moving rotation axes of the five volunteers were less than 3 mm. All the angle deviations of the mo-ving axes to the average moving rotation axes of the five volunteers were less than 5°. As to the 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 were respectively 1.697 2 mm, 1.838 3 mm and 1.321 7°. All the deviations were very small. They were all in an accep-table range of clinical practice. Conclusion: The values that represent 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 replace the traditional method in accuracy. It can make up the deficiency of the traditional fixed axis method.