Mechanical and Aeronautical Engineering, University of California at Davis, Davis, California, USA.
J Bone Joint Surg Am. 2010 Jan;92(1):98-104. doi: 10.2106/JBJS.H.01566.
Understanding the relationship between the radii of the medial and lateral femoral condyles in varus and valgus knees is important for aligning the femoral component and for restoring kinematics in total knee arthroplasty. The purpose of this study was to test the hypothesis that the asymmetry between the radii of the medial and lateral femoral condyles in varus and valgus knees with osteoarthritis is small enough to be clinically unimportant.
A magnetic resonance imaging scan was obtained with use of a biplanar, rotational alignment protocol in a consecutive series of subjects with end-stage osteoarthritis prior to total knee arthroplasty. The alignment protocol oriented the scanning plane so that both condyles were imaged in a plane perpendicular to the primary femoral axis of the knee about which the tibia flexes and extends. The study included 155 varus knees and forty-four valgus knees. Radii were calculated from the area of the best-fit circle overlaid from 10 degrees to 160 degrees on the subchondral corticocancellous bone interface of the medial and lateral femoral condyles. The radius of a condyle was the average of the radii on four adjacent images that showed the femoral condyle with the largest curvature.
In the 155 varus knees, the radius of the lateral condyle was an average of 0.1 mm larger than that of the medial condyle (p = 0.003). In the forty-four valgus knees, the radius of the lateral condyle was an average of 0.2 mm larger than that of the medial condyle (p < 0.006). There was a strong association between the radii of the medial and lateral femoral condyles in both the varus (r(2) = 0.9210) and the valgus (r(2) = 0.9129) knees.
As determined by imaging of the femoral condyles perpendicular to the primary femoral axis of the knee, the asymmetry between the radii of the medial and lateral femoral condyles in varus and valgus knees with end-stage osteoarthritis was < or =0.2 mm, which is small enough to be considered clinically unimportant when aligning a total knee prosthesis.
了解在膝内翻和膝外翻的膝关节中，股骨内外侧髁半径之间的关系对于股骨部件的对齐和全膝关节置换术中运动学的恢复非常重要。本研究的目的是验证以下假设，即在膝骨关节炎的膝内翻和膝外翻中，股骨内外侧髁半径之间的不对称性小到可以忽略不计。
在全膝关节置换术之前，对一系列终末期骨关节炎患者连续进行磁共振成像扫描，使用双平面旋转对线方案。对线方案使扫描平面定向，使得当胫骨弯曲和伸展时，两个髁都在垂直于膝关节主要股骨轴的平面上成像。该研究包括 155 例膝内翻和 44 例膝外翻。从内侧和外侧股骨髁的软骨下皮质松质骨界面上从 10 度到 160 度覆盖的最佳拟合圆的面积计算半径。股骨髁的半径是显示股骨髁曲率最大的四个相邻图像上的半径平均值。
在 155 例膝内翻中，外侧髁的半径平均比内侧髁大 0.1 毫米（p = 0.003）。在 44 例膝外翻中，外侧髁的半径平均比内侧髁大 0.2 毫米（p < 0.006）。在膝内翻（r(2) = 0.9210）和膝外翻（r(2) = 0.9129）的膝关节中，内侧和外侧股骨髁的半径之间存在很强的相关性。
通过垂直于膝关节主要股骨轴成像的股骨髁，在终末期骨关节炎的膝内翻和膝外翻中，股骨内外侧髁半径之间的不对称性<或=0.2 毫米，在对齐全膝关节假体时可以忽略不计。
