Reconciliation Between Lateral X-ray and Axial Computed Tomography Regarding Posterior Malleolus Fracture Anatomy and Medial Malleolus Involvement: A Pilot Study.

Configuration of a posterior malleolus fracture has significant variation based on mechanism of injury and concomitant ankle injuries. Radiographs obtained during early workup of ankle trauma play a pivotal role in closed reduction, surgical planning and preoperative management. Preoperative computed tomography helps distinguish fracture pathoanatomy. The purpose of this study is to relate measurements from traditional lateral radiographs with measurements on axial computed tomography. Imaging from a total of 22 patients treated at our institution from January 2008 to 2018 were evaluated. Two raters measured posterior malleolus fracture height and articular surface length on lateral radiographs, as well as medial-lateral width and anterior-posterior depth on axial computed tomography using calibrated imaging software. Posterior malleolar fractures with medial extension were recorded. Pearson correlations were calculated for all pairwise combinations of measurements. Lateral height and axial width were positively correlated. There was found to be an association between taller lateral height, and separately, wider axial width with presence of medial extension. Based on the correlations found between the measurements as well as the independent associations found with presence of medial extension, we suggest posterior-medial incision be evaluated as a potential approach in taller fractures as noted on lateral radiograph.