Department of Orthopaedics, University of Utah, 590 Wakara Way, Salt Lake City, Utah, 84108.
Department of Internal Medicine, Division of Epidemiology, University of Utah, 295 Chipeta Way, Salt Lake City, Utah, 84108.
J Orthop Res. 2019 Nov;37(11):2457-2465. doi: 10.1002/jor.24420. Epub 2019 Aug 6.
Chronic hindfoot instability is a frequent problem that includes the ankle and/or the subtalar joint. While ankle joint instability can be diagnosed clinically, accurate assessment of the subtalar joint remains elusive. This study's purpose was to assess the ability of weightbearing computed tomography (CT) scans to detect subtalar joint instability. Seven pairs of fresh frozen male cadavers (tibial plateau to toe-tip) were tested. A radiolucent frame held specimens in a plantigrade position while non-weightbearing and weightbearing CT scans (with and without torque application) were taken. First, intact ankles (Native) were scanned. Second, one specimen from each pair underwent interosseous talo-calcaneal ligament (ITCL) transection, while the contralateral underwent calcaneo-fibular ligament (CFL) transection. Third, the remaining intact ITCL or CFL was transected. Finally, the deltoid ligament was transected in all ankles. Eight radiographic measurements were performed to assess the congruency of the subtalar joint on digitally reconstructed radiographs and single CT images. Axial loading did not impact most measurements, whereas torque did impact most measurements. Radiographic measurements performed at the subtalar joint level were more reliable and better predictors for subtalar joint instability compared with measurements performed at the ankle joint level. While torque application is crucial to identify subtalar joint instability, axial load application should be avoided. Measurements to assess the subtalar joint stability should primarily be performed at the subtalar joint level rather than at the ankle joint level when using weightbearing CT scans. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2457-2465, 2019.
慢性跟骨不稳定是一种常见的问题，包括踝关节和/或距下关节。虽然踝关节不稳定可以通过临床诊断，但距下关节的准确评估仍然难以捉摸。本研究旨在评估负重 CT 扫描诊断距下关节不稳定的能力。对 7 对新鲜冷冻男性尸体（胫骨平台至趾尖）进行了测试。在足跖位下，使用透明框架固定标本，同时进行非负重和负重 CT 扫描（有和没有扭矩施加）。首先，对完整的踝关节（Native）进行扫描。其次，每对标本中的一个标本进行距下骨间跟骨-跟骨韧带（ITCL）横断，而对侧标本进行跟腓骨韧带（CFL）横断。第三，切断剩余的完整 ITCL 或 CFL。最后，所有踝关节的三角韧带均横断。在数字重建的 X 线片和单个 CT 图像上进行了 8 项放射学测量，以评估距下关节的吻合度。轴向加载不会影响大多数测量值，而扭矩会影响大多数测量值。与在踝关节水平进行的测量相比，在距下关节水平进行的放射学测量更可靠，并且是距下关节不稳定的更好预测指标。虽然扭矩施加对于确定距下关节不稳定至关重要，但应避免轴向加载。在使用负重 CT 扫描评估距下关节稳定性时，应主要在距下关节水平而不是在踝关节水平进行测量。 © 2019 骨科研究协会。由 Wiley Periodicals, Inc. 出版。J Orthop Res 37:2457-2465, 2019.
