de Cesar Netto Cesar, Pinto Martim, Roberts Lauren, Lee Sung Ro, Roney Andrew R, Naranje Sameer, Godoy-Santos Alexandre Leme, Shah Ashish
Hospital for Special Surgery, Department of Foot and Ankle Orthopedics, 535 East 70thStreet, New York, NY, 10021, United States; University of Alabama at Birmingham (UAB), Department of Orthopedics, Birmingham, AL, United States.
University of Alabama at Birmingham (UAB), Department of Orthopedics, Birmingham, AL, United States.
Injury. 2018 Oct;49(10):1758-1762. doi: 10.1016/j.injury.2018.08.005. Epub 2018 Aug 7.
Precise diagnosis of distal tibiofibular syndesmotic injury is challenging, and a gold standard diagnostic test has still not been established. Tibiofibular clear space identified on radiographic imaging is considered the most reliable indicator of the injury. The Cotton test is the most widely used intraoperative technique to evaluate the syndesmotic integrity although it has its limitations. We advocate for a novel intra operative test using a 3.5 mm blunt cortical tap.
Tibiofibular clear space was assessed in nine cadaveric specimens using three sequential fluoroscopic images. The first image was taken prior to the application of the tap test (intact, non-stressed). Then, a 2.5 mm hole was drilled distally on the lateral fibula, and a 3.5 mm cortical tap was then threaded in the hole. The tap test involved gradually advancing the blunt tip against the lateral tibia, providing a tibiofibular separation force (intact, stressed). This same stress was then applied after all syndesmotic ligaments were released (injured, stressed). Measurements were compared by one-way ANOVA and paired Student's t-test. Intra and inter-observer agreements were evaluated by intraclass correlation coefficient (ICC). P-values <.05 were considered significant.
We found excellent intra-observer (0.97) and inter-observer (0.98) agreement following the imaging assessment. Significant differences were found in the paired comparison between the groups (p < .05). When using an absolute value for TFCS >6 mm as diagnostic for coronal syndesmotic instability, the tap test demonstrated a 96.3% sensitivity and specificity, a 96.3% PPV and NPV and a 96.3% accuracy in diagnosing coronal syndesmotic instability.
Our cadaveric study demonstrated that this novel coronal syndesmotic instability test using a 3.5 mm blunt cortical tap is a simple, accurate and reliable technique able to demonstrate significant differences in the tibiofibular clear space when injury was present. It could represent a more controlled and stable alternative to the most used Cotton test.
胫腓下联合损伤的精确诊断具有挑战性，目前仍未确立金标准诊断试验。影像学上确定的胫腓间隙被认为是该损伤最可靠的指标。尽管有其局限性，但科顿试验是评估胫腓联合完整性最广泛使用的术中技术。我们提倡使用一种新型的术中试验，即使用3.5毫米钝性皮质骨锥。
使用三张连续的透视图像评估九个尸体标本的胫腓间隙。第一张图像在应用骨锥试验前拍摄（完整，未受力）。然后，在腓骨远端钻一个2.5毫米的孔，接着将一个3.5毫米的皮质骨锥拧入该孔。骨锥试验包括将钝性尖端逐渐推向胫骨外侧，施加胫腓分离力（完整，受力）。在所有胫腓联合韧带松解后（损伤，受力）施加相同的应力。测量值通过单因素方差分析和配对学生t检验进行比较。观察者内和观察者间的一致性通过组内相关系数（ICC）进行评估。P值<.05被认为具有显著性。
我们发现在影像学评估后观察者内一致性良好（0.97），观察者间一致性良好（0.98）。在各分组之间的配对比较中发现了显著差异（p<.05）。当使用胫腓间隙绝对值>6毫米作为冠状面胫腓联合不稳定的诊断标准时，骨锥试验在诊断冠状面胫腓联合不稳定方面显示出96.3%的敏感性和特异性、96.3%的阳性预测值和阴性预测值以及96.3%的准确性。
我们的尸体研究表明，这种使用3.5毫米钝性皮质骨锥的新型冠状面胫腓联合不稳定试验是一种简单、准确且可靠的技术，能够在存在损伤时显示胫腓间隙的显著差异。它可能是最常用的科顿试验的一种更可控、更稳定的替代方法。
