Retrospective Chart Review: Weight Bearing CT Scans and the Measurement of the Tibiofibular Syndesmosis

• Published in: Foot & ankle orthopaedics 2022-01, Vol.7 (1), p.2473011421S00194
• Main Authors: Falcon, Spencer, McCormack, Thomas J., Mackay, Matthew, Tarakemeh, Armin, Mullen, Scott, Schroeppel, Paul, Wolf, Megan R., Vopat, Bryan G.
• Format: Article
• Language: English
• Subjects: Medical imaging
• ISSN: 2473-0114; 2473-0114
• DOI: 10.1177/2473011421S00194

Category: Ankle Introduction/Purpose: Tibiofibular Syndesmosis injuries are commonly misdiagnosed due to their unreliable projection on plain films. Many studies have striven to establish baseline measurements of the distal tibial and fibular articulation. While cadaver, MRI, ultrasound, and non-weight bearing computer tomography (CT) have been utilized, weight bearing CT (WBCT) scans are a relatively new imaging modality that has not yet been utilized to establish reproducible and widely-referenced baseline anatomic positions. The hypotheses of this study are: 1. Standing, weight bearing CT scan will allow for evaluation and measurement of the tibio-fibular syndesmosis. 2. There will be no side to side variation or sex-based differences in syndesmosis measurements. Methods: A retrospective chart review was conducted using the electronic medical record. Inclusion criteria was applied as follows: Patients who have undergone weight bearing CT of the bilateral lower extremities from 2018 to 2020. One hundred twenty ankle CT scans were acquired for measurements. Measurements were collected by two independent reviewers twice in order to achieve inter- and intra-reliability. The measurements were then analyzed in order to establish a baseline for normal anatomy, compare injured to non-injured side, and observe any sex-based differences. Results: Measurements of uninjured legs were utilized to define normal parameters for tibiofibular syndesmosis on weight bearing CT. Averages were found for measurements of anterior incisura 3.2mm (SD=1.1mm), middle incisura 3.9mm (SD=1.1mm), posterior incisura 5.6mm (SD=1.7mm), alpha angle 16.3° (SD=6.3°), medial clear space 2.2mm (SD=0.6mm).Patients with syndesmotic injuries had significantly larger measurements for anterior (p