Relevance of posterior malleolar fracture fixation to ankle syndesmotic reduction, a comparative study

Background: Appropriate distal tibiofibular syndesmotic reduction is crucial to restore ankle stability, guard against future arthrosis with worse functional outcome. Optimal technique for syndesmotic reduction has been a matter of debate. This study aimed at radiological evaluation of syndesmotic integrity following two methods of reduction (posterior malleolar fixation and trans-syndesmotic screw fixation), additionally, correlating the posterior malleolus size to the radiological results of both techniques.Methods: Syndesmotic integrity was compared after each technique as per translational and rotational fibular positions. Utilizing, preoperative and postoperative computed tomography scans of injured ankle, the fibular antero-posterior and Medio-lateral translation distances were measured. Additionally, the fibular rotation angle was calibrated. Incidence of inadequate reduction in each group was reported. Preoperative and postoperative radiological findings were compared and correlated to posterior malleolus size in relation to tibial articular distance.Results: A significant difference between both techniques was noted in term of fibular rotation. In patients with PM ˂ 10% of tibial articular surface, a significant difference was obvious in postoperative AP-translational and rotational findings between both techniques. Overall malreduction incidence rate of 68.9% was reported in this study, with 84.7% rate in patients managed with SS-fixation, whilst 51.2% rate in those managed via PM-fixation.Conclusions: Posterior malleolar fixation could limit syndesmotic malreduction risk whatsoever it’s size. Approaching CT reference values for syndesmotic reduction might benefit preoperative planning and detect intraoperative malreduction. Further future clinical studies correlating these findings to clinical outcome would be more helpful