股骨远端轴位X射线片对全膝关节假体置换术中股骨假体旋转力线的评估价值

Axial radiography of the distal femur to access rotational alignment in total knee arthroplasty

目的:探讨股骨远端轴位X射线片对于确定股骨后髁扭转角的价值及在全膝关节假体置换术中的意义。方法:选择2004-01/2005-05在南方医院接受全膝关节置换术的患者22例,共30例膝(均可以弯曲到90°)行术前的股骨远端轴位X射线检查和膝关节CT扫描。轴位X射线片在膝关节屈曲90°,小腿重力牵引下拍摄,CT采用1mm薄层扫描。在X射线片和CT片上,分别标记出临床上髁轴和后髁轴,并计算出股骨后髁扭转角。应用SPSS13.0软件两组数据进行方差分析和相关性分析。结果:受检股骨远端在轴位X射线片上都得到了良好的显示,患者在检查过程中没有感到明显的不适。由轴位X射线片和CT片上测得的股骨后髁扭转角分别为(6.9±1.6)°,(6.8±1.5)°,两种方法测得的股骨后髁扭转角平均差值为(0.6±0.5)°,无显著性差异,且存在强相关(r=0.903,P<0.001)。结论:股骨远端轴位X射线片可用于全膝关节置换术前确定股骨假体旋转力线,具有同CT相当的准确性。

AIM： To discuss the value of the axial radiography of distal femur in the assessment of rotational alignment in total knee arthroplasty. METHODS： Twenty-two patients of 30 knees, which could bend at 90°, with total knee arthroplasty in Nanfang Hospital were selected between January 2004 and May 2005. They were subjected to axial radiographs of distal femur and CT scan for knee joint. The radiographs were taken while the knee was in 90° flexion and the calf underwent gravity traction. The CT scan was operated with a thin layer of 1 mm. The angle between the clinical epicondylar axis and the posterior condylar axis was measured in radiograph and CT films and the results were given variance analysis and correlative analysis with SPSS 13.0 software. RESULTS： The examined distal femur was well displayed in the axial radiography, and there was no obvious uncomfortableness diJring examination. The posterior condylar angles were （6.9±1.6）° and （6.8±1.5）° in axial radiography and CT scanning, respectively. The mean discrepancy between the two methods was （0.6±0.5）°, indicating there was no significant difference between the two methods, and a strong correlation was observed （r =0.903, P〈 0,001）. CONCLUSION： The axial radiography of distal femur is acceptable for evaluating femoral component rotation with comparable accuracy as CT.