Abstract

Purpose

A lack of specific intra-operative markers for accurate positioning of the syndesmotic screw can result in its malpositioning. Knowledge of the axial orientation of the syndesmosis can help in reducing this risk of malpositioning of the syndesmotic screw. In this CT-based study, we investigated the axial relationships of intact syndesmoses with various rigid bony landmarks around the ankle joint that were independent of foot and horizontal plane.

Methods

We analyzed 126 CT-based studies of uninjured normal ankle joints and defined the following bony landmarks: posteromedial and posterolateral surface of the distal tibia, bimalleolar tips, and anterior and posterior extents of both malleoli. Axial differences between coronal plane through the central axis of syndesmosis and modified coronal planes through these bony landmarks were then measured. Software-based lateral radiographs were created with the reference coronal plane for each radiograph being kept perpendicular to the plane of the viewing screen.

Results

The mean axial differences parting the syndesmotic axis from the modified coronal planes based on distal tibial posteromedial surface, distal tibial posterolateral surface, bimalleolar tips, anterior bimalleolar extents, and posterior bimalleolar extents were − 3.15°, 13.73°, 4.10°, 11.95°, and 12.24°, respectively. With the exception of the posterolateral surface of the distal tibia, all other bony landmarks were radiologically identifiable in the majority of cases.

Conclusion

Our study attempts to provide a solution to the issues related to malpositioning of the syndesmotic screw by providing new bony landmarks that can be clinically and fluoroscopically used for syndesmotic-screw positioning. The relationships of bimalleolar tips, anterior and posterior bimalleolar extents, and the posteromedial surface can be reliably used as landmarks for directing syndesmotic screws.

中文翻译：

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理想的双下颌联合螺钉定位的新标志：基于计算机断层扫描的分析和射线照相模拟。

摘要

目的

缺少精确的术中标记，无法准确定位下颌骨螺钉。了解下颌骨的轴向定向可以帮助降低这种下颌骨螺钉错位的风险。在这项基于CT的研究中，我们研究了完整的脚踝联合与踝关节周围各种刚性骨标志物（与脚和水平面无关）的轴向关系。

方法

我们分析了未经损伤的正常踝关节的126个基于CT的研究，并定义了以下骨标志：胫骨远端的后内侧和后外侧表面，双小叶尖端以及两个踝部的前后范围。然后测量通过牙合的中心轴的冠状平面和通过这些骨性界标的改良冠状平面之间的轴向差异。创建基于软件的横向X射线照片，使每个X射线照片的参考冠状平面保持垂直于观察屏的平面。

结果

基于胫骨远端后外侧表面，胫骨远端后外侧表面，双小叶尖端，前双小叶范围和后双小肌范围，从改良的冠状平面将共生轴分开的平均轴向差为− 3.15°，13.73°，4.10°，11.95°，和12.24°。除胫骨远端的后外侧表面外，在大多数情况下，所有其他骨标志均在放射学上是可识别的。

结论

我们的研究试图通过提供可以在临床上和透视下用于下颌骨螺钉定位的新骨标志物，来解决与下颌骨螺钉定位错误相关的问题。颌骨尖端，前，后颌骨范围以及后内侧表面之间的关系可以可靠地用作引导股骨联合螺钉的界标。