| Description: |
Category: Ankle, Trauma Keywords: Syndesmotic Injury, Biomechanics, Weight Bearing CT Introduction/Purpose: Accurate diagnosis of syndesmotic disruption remains a challenge, as conventional radiographs and CT demonstrate limited sensitivity, detecting subtle instability in only up to 67% of cases. Missed injuries can lead to chronic pain, loss of function, and post-traumatic arthritis, highlighting the need for more reliable diagnostic methods. Weightbearing CT (WBCT) enables three-dimensional assessment of the ankle under physiologic load, with the potential to quantify fibular and talar displacement relative to the tibia. However, objective criteria for classifying syndesmotic injury on WBCT have not been established. This study aimed to evaluate whether referencing the contralateral ankle as an internal control during standard-of-care WBCT evaluation can improve diagnostic accuracy by quantifying translational and rotational differences of the fibula and talus relative to the tibia. Methods: This IRB-approved study evaluated 36 fresh-frozen through-the-knee cadaveric specimens (22 male, 14 female), each scanned bilaterally with WBCT under a 356N axial load. Scans were obtained in the intact state and again following sectioning of all syndesmotic ligaments (AITFL, interosseous ligament, distal 3 cm of interosseous membrane, PITFL) while preserving the deltoid complex, lateral ligaments, and superior peroneal retinaculum. Three-dimensional bone models were analyzed using an automated tibial coordinate system pipeline with point-cloud registration to generate fibular and talar translations and rotations relative to the tibia. Six kinematic parameters were quantified, comprising mediolateral, anteroposterior, and superoinferior translations, together with rotations about the same axes. As these parameters are correlated and do not occur in isolation, dimensionality reduction was performed with principal component analysis prior to predictive modeling. Matched-pair conditional logistic regression then compared ... |