Abstract

Objective

Hindfoot valgus malalignment has been assessed on coronal MRI by the measurement of the tibio-calcaneal (TC) angle and apparent moment arm (AMA). This study aimed to determine if the calcaneofibular ligament (CFL) angle could be used as a further marker of hindfoot valgus malalignment on routine non-weight-bearing ankle MRI.

Material and methods

One hundred ninety-five consecutive 3-T ankle MRI studies were identified from the hospital PACS system. The TC and CFL angles could be measured in 155 cases (78%), and the AMA on 153 cases.

Results

The study group comprised 56 males and 72 females with a mean age of 46 years (range 4–89 years). In 27 patients, both ankles had been imaged. The Pearson correlation between the TC and CFL angles was −0.43, with a corresponding p value of 0.001 indicating a strong negative correlation between the TC and CFL angles. The CFL angle was significantly lower in those with hindfoot valgus (113 ± 14) compared with those without (123° ± 15°) (p = 0.001). The optimal cut-off point of the CFL angle for hindfoot valgus was ≤119°, with a sensitivity and specificity of 66% and 63% respectively. The Pearson correlation between the CFL angle and AMA was −0.10, with a corresponding p value of 0.21 indicating a weak negative correlation that did not reach statistical significance.

Conclusion

Hindfoot valgus as estimated by the increased TC angle on coronal non-weight-bearing ankle MRI is associated with a reduced CFL angle on sagittal MR images, but is not associated with AMA. Therefore, a horizontal orientation of the CFL on sagittal MR images may be a further useful sign of hindfoot valgus.

中文翻译：

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水平跟腓韧带：踝部MRI显示后足外翻的迹象

摘要

目的

通过测量胫骨跟骨（TC）角和表观力矩臂（AMA）在冠状MRI上评估了后足外翻畸形。这项研究旨在确定跟骨腓骨韧带（CFL）角是否可以作为常规非承重踝MRI上后足外翻畸形的进一步标志。

材料与方法

从医院的PACS系统中识别出195例连续的3-T踝部MRI研究。可以测量155例（78％）的TC和CFL角，以及153例的AMA。

结果

该研究组由56位男性和72位女性组成，平均年龄为46岁（4至89岁）。在27例患者中，两个脚踝均已成像。TC和CFL角度之间的Pearson相关性为-0.43，对应的p值为0.001，表明TC和CFL角度之间的相关性很强。有后足外翻者的CFL角度（113±14）显着低于无后足者（123°±15°）（p = 0.001）。后足外翻的最佳CFL角分界点为≤119°，敏感性和特异性分别为66％和63％。CFL角与AMA之间的Pearson相关性为-0.10，相应的p 值为0.21，表明没有相关的微弱的负相关性。

结论

通过冠状非负重踝MRI的TC角度增加估计的后足外翻与矢状MR图像的CFL角度减小相关，但与AMA不相关。因此，CFL在矢状MR图像上的水平方向可能是后足外翻的另一个有用标志。