股骨上髁轴与股骨外旋截骨角度的相关性研究

Correlation study of the trans-epicondylar axis and femoral external rotation osteotomy in the total knee arthroplasty

目的探讨股骨上髁轴与全膝置换术中股骨外旋截骨角度的相关性。方法收集2008年10月至2011年3月在上海瑞金医院骨科就诊患者64例(118个膝关节)。采用CT扫描结合Photoshop软件对股骨远端影像学图像处理,对性别、侧别、内髁选取点、不同年龄组进行后髁角测量和差异的统计学比较。并将术前测量的后髁角,与最终进行手术的28个膝关节术中实际设置的股骨假体外旋进行相关性分析。结果不同性别、侧别、内髁选取点不同对后髁角并无影响,年龄组中80岁以上的右膝后髁角与70岁以下组有统计学差异(P<0.05),但可能是由于样本量较小和个体差异值较大所引起;术中假体外旋角=4.58+0.05×术前后髁角,相关系数r=0.057,决定系数R2=0.0033,不能确认两者之间有必然的联系。结论对于骨关节炎患者,如仅依据后髁角决定股骨假体的旋转,容易造成误差,使用平衡间隙法进行截骨具有可行性。

Objective To study the correlation study of the trans-epicondylar axis and femoral prosthesis external rotation in the total knee arthroplasty. Mothods After a collection of 64 patients with knee osteoarthritis （118 knees）CT images from October 2008 to March 2011 in Shanghai Ruijin Hospital, we use Photoshop to handle the images and make statistical comparison with gender, sides, the interior condylar which we chose, and the difference in the different ages group for the post condylar angle （PCA） were measured. We also want to find out the correlation between the 28 knee＇s PCA before the surgery we measured and the actual femoral prosthesis external rotation in the total knee arthroplasty. Results Different gender,sides,the interior condylar which we chose had no impact on the PCA. Statistical difference （P〈0.05） was found beween the group of over age 80 and under age 70. It may be caused by small sample size and individual difference; the actual femoral prosthesis external rotation=4.58＋0.05×PCA before the surgery were measured, r=0.057 coefficient of determination R2=0.0033, we cannot think they have inevitable connection. Conclusions To the patients with osteoarthritis, if we just determine the femoral prosthesis rotation by PCA, we will have inevitably errors in results, the method of balance gap is feasible to judge the external rootation.