Diagnosing Chronic Diastasis of the Syndesmosis A Novel Measurement Using Computed Tomography

Background:Chronic diastasis of the syndesmosis has been recognized as a cause of persistent pain and dysfunction after a rotational ankle injury. Recently, there has been an increased effort to define the use of computed tomography (CT) imaging in making this diagnosis; however, no clear consensus has been reached on the best way to assess the anatomical integrity of the syndesmosis. In this retrospective case series, we have evaluated the diagnostic capability of 2 novel CT-based measurements.Methods:Fourteen patients with symptomatic syndesmotic instability received a bilateral ankle CT scan. Two measurements were performed. The first measurement was the angle subtended by 2 lines drawn tangent to the anterior and posterior surfaces of the distal tibia and lateral malleolus 1 cm above the talar dome. The second measurement was the area bound by these lines, the lateral tibia and the medial aspect of the lateral malleolus. The injured and contralateral sides were compared using a Wilcoxon rank sum test ...