髌骨轴位摄影角度与屈膝角度的相关性

Correlation of patella axial angle and knee angle radiophotography

目的探讨髌骨轴位摄影角度与屈膝角度的相关性。方法选取30例患者的标准髌骨侧位膝关节屈膝过程的动态影像。在髌骨侧位动态影像中,以股骨前缘线与胫骨前缘线的夹角作为胫股角,以股骨前缘线与髌骨后缘线的夹角作为髌股角(X线入射角度),选择胫股角为50°～170°,每隔5°分别测量对应的髌股角。统计各胫股角相对应的髌股角的均值,对测量数据进行相关分析和回归分析。结果胫股角在50°～110°范围时,胫股角和髌股角存在直线相关关系(r=0.92,P<0.01),回归方程为Y=60.71+0.60X。胫股角在115°～170°范围时,胫股角与髌股角的差值(髌胫角)基本恒定,其均值为15.04°±3.76°。结论髌骨轴位摄影角度与胫股角具有直线相关性,在髌骨轴位摄影中可根据回归方程Y=60.71+0.60X或15°角选择相应的摄影角度。

Objective To investigate the correlation of patellar axis angle and knee angle with digital radiophotography. Methods The standard dynamic images of lateral patella knee flexion of 30 patients were selected. In patellar lateral dynamic images,the angle between the front line of femur and tibia was defined as a tibiofemoral angle,and the patellofemoral angle,which was X ray incident angle,was referred to the angle between the front line of femur and the trailing edge of patella. Then the tibiofemoral angle varied from 50° to 170° with increase of 5°,and the corresponding patellofemoral angle was measured respectively. Correlation and regression of tibiofemoral angle and its corresponding patellofemoral angle were analyzed. Results When tibiofemoral angle varied from 50° to 110°,the patellofemoral angle changed linearly （r=0.92,P0.01）,and the regression equation was Y=60.71＋0.60X. When tibiofemoral angle increased from 115° to 170°,the difference between patellofemoral angle was almost constant,with a value of 15.04°±3.76°. Conclusion In the patellar axis position radiophotography,axial angle of the patella and tibiofemoral angle has linear correlation,and the appropriate camera angles can be obtained according to the regression equation Y=60.71＋0.60X or patellar tibial angle of 15°.