Department of Orthopaedic Surgery, Hallym University Kangnam Sacred Heart Hospital, 1, Singil-ro, Yeongdeungpo-gu, Seoul, South Korea.
Department of Orthopaedic Surgery, Konkuk University Medical Center, 120-1, Neungdong-ro, Gwangjin-gu, Seoul, South Korea.
Knee. 2021 Dec;33:24-30. doi: 10.1016/j.knee.2021.08.022. Epub 2021 Sep 16.
Before total knee arthroplasty (TKA), rotational assessment of the distal femur can be performed using either magnetic resonance imaging (MRI) or computed tomography (CT). Until now, there has been no study comparing the two modalities regarding rotational assessment of the distal femur in the same patients.
We retrospectively reviewed the preoperative CT and MRI images of 110 knees in 110 patients who underwent TKA. In the axial planes of CT and MRI scan, the posterior condylar axis (PCA), anatomical transepicondylar axis (aTEA), and perpendicular line to anteroposterior axis (pAPA) were identified; the angles between these studied lines were calculated. During TKA, the angles measured on the preoperative CT and MRI were compared with the measurements obtained in the intraoperative field.
The mean aTEA-PCA angle was 6.2 ± 1.9° with CT and 5.1 ± 1.8° with MRI. The mean pAPA-PCA angle was 4.7 ± 2.1° with CT and 3.5 ± 2.0° with MRI. The mean aTEA-PCA (1.1 ± 1.3°, p = 0.001) and pAPA-PCA (1.2 ± 1.2°, p = 0.012) angles significantly differed between CT and MRI. Intra-operatively, the mean aTEA-PCA angle was 4.7 ± 1.1° and the mean pAPA-PCA angle was 3.2 ± 0.9°. Reliability analysis between the preoperative CT/MRI and the intraoperative measurements gave kappa values of 0.72 for aTEA-PCA and 0.66 for pAPA-PCA with CT, and 0.82 for aTEA-PCA and 0.84 for pAPA-PCA with MRI.
Preoperative rotational assessment of the distal femur with CT may cause higher external rotation of femoral component in TKA.
在全膝关节置换术（TKA）之前，可以使用磁共振成像（MRI）或计算机断层扫描（CT）来评估股骨远端的旋转。到目前为止，还没有研究比较这两种方法在同一患者的股骨远端旋转评估方面的差异。
我们回顾性分析了 110 例接受 TKA 的患者的 110 个膝关节的术前 CT 和 MRI 图像。在 CT 和 MRI 扫描的轴位平面上，确定了后髁轴（PCA）、解剖髁间轴（aTEA）和与前后轴垂直的线（pAPA）；计算了这些研究线之间的角度。在 TKA 过程中，将术前 CT 和 MRI 上测量的角度与术中获得的测量值进行比较。
CT 上的平均 aTEA-PCA 角为 6.2±1.9°，MRI 上为 5.1±1.8°。CT 上的平均 pAPA-PCA 角为 4.7±2.1°，MRI 上为 3.5±2.0°。CT 与 MRI 相比，aTEA-PCA（1.1±1.3°，p=0.001）和 pAPA-PCA（1.2±1.2°，p=0.012）的角度差异有统计学意义。术中，aTEA-PCA 角的平均值为 4.7±1.1°，pAPA-PCA 角的平均值为 3.2±0.9°。CT 术前 CT/MRI 与术中测量的可靠性分析得出 aTEA-PCA 的kappa 值为 0.72，pAPA-PCA 的 kappa 值为 0.66；MRI 的 aTEA-PCA 的 kappa 值为 0.82，pAPA-PCA 的 kappa 值为 0.84。
术前使用 CT 评估股骨远端的旋转可能会导致 TKA 中股骨组件的外旋增加。
