Combining radiographic and CT measurements to rival MRI for the diagnosis of acute isolated syndesmotic injury.

ABSTRACT

BACKGROUND: Acute isolated syndesmotic injuries (AISIs) have a high potential to be misdiagnosed or underdiagnosed at initial presentation to the hospital. Although magnetic resonance imaging (MRI) is the gold standard in noninvasive diagnostics, it is not always available immediately and is much more expensive than other imaging modalities. This study identifies improvements in conventional radiography and computed tomography (CT) to diagnose AISI and aims to reduce the number of MRI scans needed to verify the diagnosis. METHODS: A retrospective case match control study was conducted by searching our trauma database between 2008 and 2022. A study group of patients with AISI (n = 64) and a control group of patients without AISI (n = 76) were formed to generate an equal number of images from both groups (62 radiographs and 22 CT scans). A total of 16 parameters that quantify the distal tibiofibular relation in injured and uninjured ankles were analyzed. For statistical analysis, a two-sided t-test was applied to calculate significant differences (p < 0.05). In a further step, a receiver operating characteristic curve (ROC) was used to determine cut-off values for the most significant parameters. RESULTS: The most significant measurement (p < 0.001) on axial CT scans was the syndesmotic area (SA). The ROC curve revealed an area under the curve (AUC) of 0.94 (95% CI 0.86-1.0) and a cut-off value of 71.68 mm2 that shows a sensitivity and specificity of 95.5% and 81.8%, respectively. CONCLUSION: This study suggests that radiographic imaging could represent an equally accurate alternative to MRI. These methods might generate the correct diagnosis faster due to their availability and inexpensiveness. By applying our new cut-off values in a clinical setting, the number of underdiagnosed and untreated unstable syndesmotic injuries could be reduced. LEVEL OF EVIDENCE III, retrospective comparative study.