Normal Tibiofibular Relationship at the Syndesmosis on Axial CT Imaging
Reference: Dikos GD, Heisler J, Choplin RH, Weber. Normal Tibiofibular Relationship at the Syndesmosis on Axial CT Imaging. J Orthop Trauma. 2012 Jul; 26(7): 433-8.
Scientific Literature Review
Reviewed by: Irene Labib, DPM
Residency Program: University Hospital – UMDNJ
The author's purpose was to define normal tibiofibular relationships at the syndesmosis on axial CT imaging and to report the intra- and interrater reliability of these measurements.
The study included patients between the ages of 18-40 (mean 28.1 years). Their exclusion criteria consisted of patients with history of ankle fractures, syndesmotic injuries, chronic ankle instability, ankle arthrosis or previous ankle surgery. A total of 30 patients (60 ankles) were included in the study. The AOFAS scaling system was utilized to exclude subjective or functional impairments.
The authors then performed a physical examination, radiographic evaluation using AP, lateral, and mortise view of the ankles, and bilateral CT scans measuring tibiofibular clear space (TFCS), tibiofibular overlap (TFO), and anterior tibiofibular (ATF) interval.
Gender differences were found among the patients. Males had greater height, weight, and tibial length while females had greater sagittal arcs and subtalar valgus motion. They also found that males had greater TFCS, TFO and ATF intervals on AP views. Poor interrater and intrarater reliability of radiographic TFCS and TFO measurements were found. This is attributed to the fact that radiographic parameters vary with rotation. Any slight rotation will change the linear relationships of TFCS and TFO.
It is crucial to obtain anatomic reduction of the syndesmosis following fracture reduction. The authors conclude that CT is more sensitive in detecting diastasis than plain radiographs.