OrthoSport Victoria, Richmond, Melbourne, Victoria, Australia.
Healthcare Imaging Services, Richmond, Victoria, Australia.
Am J Sports Med. 2019 Oct;47(12):2895-2903. doi: 10.1177/0363546519868219. Epub 2019 Aug 21.
The Kaplan fibers (KFs) of the iliotibial band have been suggested to play a role in anterolateral rotational instability of the knee, particularly in the setting of an anterior cruciate ligament (ACL) rupture. Description of the normal magnetic resonance imaging (MRI) anatomy of the KFs may facilitate subsequent investigation into the MRI signs of injury.
To assess if the KF complex can be identified on 3-T MRI using standard knee protocols.
Cohort study (diagnosis); Level of evidence, 3.
3-T MRI scans of 50 ACL-intact knees were reviewed independently by a musculoskeletal radiologist and 2 orthopaedic surgeons. Identification of the KFs was based on radiological diagnostic criteria developed a priori. Identification of the KFs in the sagittal, coronal, and axial planes was recorded. Interobserver reliability was assessed using the Kappa statistic. Detailed anatomy including distance to the joint line and relationship to adjacent structures was recorded.
The mean patient age was 43 years (range, 15-81 years), 58% were male, and 50% were right knees. The KFs were identified by at least 2 reviewers on the sagittal images in 96% of cases, on the axial images in 76% of cases, and on the coronal images in 4% of cases. The mean distance from the KF distal femoral insertion to the lateral joint line was 50.1 mm (SD, 6.6 mm) and the mean distance to the lateral gastrocnemius tendon origin was 10.8 mm (SD, 8.6 mm). The KFs were consistently identified immediately anterior to the superior lateral geniculate artery on sagittal imaging. Interobserver reliability for identification was best in the sagittal plane (Kappa 0.5) and worst in the coronal plane (Kappa 0.1).
The KF complex can be identified on routine MRI sequences in the ACL-intact knee; however, there is low to moderate interobserver reliability. Imaging in the sagittal plane had the highest rate of identification and the coronal plane the lowest. There is a consistent relationship between the most distal KF femoral attachment and the lateral joint line, lateral gastrocnemius tendon, and superior lateral geniculate artery.
髂胫束（ITB）的 Kaplan 纤维（KF）被认为在膝关节前外侧旋转不稳定中起作用，尤其是在前交叉韧带（ACL）断裂的情况下。描述 KF 的正常磁共振成像（MRI）解剖结构可能有助于进一步研究 MRI 损伤的征象。
评估是否可以使用标准膝关节协议在 3-T MRI 上识别 KF 复合体。
队列研究（诊断）；证据水平，3。
50 例 ACL 完整膝关节的 3-T MRI 扫描由 1 名肌肉骨骼放射科医生和 2 名骨科医生独立进行回顾。根据事先制定的放射学诊断标准识别 KF。记录 KF 在矢状面、冠状面和轴面的位置。使用 Kappa 统计评估观察者间的可靠性。记录详细的解剖结构，包括与关节线的距离和与相邻结构的关系。
患者的平均年龄为 43 岁（范围，15-81 岁），58%为男性，50%为右膝。至少有 2 位观察者在矢状图像上识别出 KF 的比例为 96%，在轴位图像上为 76%，在冠状图像上为 4%。KF 远端股骨附着点到外侧关节线的平均距离为 50.1mm（SD，6.6mm），到外侧腓肠肌腱起点的平均距离为 10.8mm（SD，8.6mm）。KF 在矢状图像上始终位于外侧上髁状突动脉的前侧。观察者间识别的可靠性在矢状面最佳（Kappa 0.5），在冠状面最差（Kappa 0.1）。
在 ACL 完整的膝关节中，常规 MRI 序列可以识别 KF 复合体；然而，观察者间的可靠性较低。矢状面的识别率最高，冠状面的识别率最低。KF 的最远端股骨附着点与外侧关节线、外侧腓肠肌腱和外侧上髁状突动脉之间存在一致的关系。
