MRI辅助下膝关节骨关节炎伴内翻畸形患者股骨远端3种旋转轴线与外科经股骨上髁轴的准确性比较

Accuracy of 3 femoral rotation axes for osteoarthritis with varus deformity of knee joint based on MRI: a comparative study of 86 knees with surgical transepicondylar axis

目的在磁共振（magnetic resonance imaging,MRI）上测量膝关节重度骨关节炎（osteoarthritis）伴内翻畸形患者股骨远端不同旋转轴线,评估各参照轴线相对于外科经股骨上髁轴（surgical transepicondylar axis,STEA）的准确性。方法回顾性分析2013年6月至2014年1月在我中心明确诊断为膝关节重度骨关节炎伴内翻畸形患者（内翻≤15°）86例（86膝）的临床资料,其中男性34例,女性52例;年龄51~70（63.7±8.7）岁,由2位医师在MRI横断面图像上定位STEA、临床经股骨上髁轴（clinical transepicondylar axis,CTEA）、后踝轴（posterior condylar line,PCL）外旋3°线（3°extorsion against PCL,3°PCL）、前后轴（anterior posterior line,APL）的垂线,测量各轴线相对于STEA偏差的角度,并用方差分析比较各角度接近STEA的精确性。结果 3°PCL相对于STEA外旋（0.63°±1.82°）、CTEA相对于STEA外旋（3.78°±0.75°）,APL垂线相对于STEA外旋（5.38°±3.17°）,精确度：A角（3°PCL相对于STEA旋转的角度）〉CSA（CTEA相对于STEA旋转的角度）〉ASA（APL垂线相对于STEA旋转的角度）,各角度两两比较差异具有统计学意义（P〈0.01）。结论膝关节重度骨关节炎伴轻度内翻人群中,股骨远端截骨轴线除STEA外,3°PCL准确性最高;术中STEA定位困难时,参照3°PCL进行截骨可获得较好的股骨旋转准确度。

Objective To evaluate the accuracy of different axes relative to surgical transepicondylar axis （STEA） by measuring the distal femur with different rotation axes for the patients suffering from severe osteoarthritis with varus deformity of knee joint on MR images. Methods A retrospective analysis was performed on 86 cases who had severe osteoarthritis in knee （86 knees） with varus deformity （varus deformity ≤15°） in our center between June 2013 and January 2014. They were 34 males （34 knees） and 52 females （52 knees） , at an aged from 51 to 70 years （mean 63.7 years）. MR imaging was applied to locate the STEA, the clinical transepicondylar axis （ CTEA）, 3 o extorsion against the posterior femoral condylar line （ 3 o PCL） , and the anterior posterior line （APL） by 2 surgeons respectively. Then the deviation relative to the STEA among 3° PCL, the CTEA, and the perpendicular of APL were observed. Analysis of variance （ANOVA） was used to compare the accuracy of the angle close to STEA. Results 3°PCL relative to STEA （Angel A） was out 0.63° ± 1.82°, CTEA to STEA （CSA） was out 3.78°±0.75°, and perpendicular of anterior posterior line to STEA （ASA） was out 5.38°± 3.17°, in an accuracy of Angle A 〉 CSA 〉 ASA. There was statistical significance in any two-angle comparison （ P 〈 0.01 ）. Conclusion In the patients suffering from severe osteoarthritis knee with mild varus deformity, except STEA, 3° PCL is of the highest accuracy in the distal femoral bone cutting axis. When it is difficult to locate STEA during operation, 3° PCLis helpful to obtain a good femoral rotation accuracy.