Intraoperative syndesmotic reduction: three-dimensional versus standard fluoroscopic imaging.

Background: The quality of reduction of the syndesmosis is an important factor in the outcome of ankle fractures associated with a syndesmotic injury. The purpose of this study was to directly compare the accuracy of syndesmotic reductions obtained using intraoperative standard fluoroscopic techniques against reductions obtained using three-dimensional imaging of the Iso-C3D fluoroscope.
Methods: We prospectively reviewed imaging studies of patients who were diagnosed as having preoperative or intraoperative evidence of syndesmotic diastasis (on the basis of the fluoroscopic Cotton test and/or a manual external rotation stress test) who underwent syndesmotic fixation at one of two level-I trauma centers. Center A used intraoperative computed tomography (CT) imaging to assess reduction (≤2 mm), while Center B assessed reduction under standard fluoroscopic imaging. Postoperative alignment was assessed in a standardized manner, measuring anterior fibular distance, posterior fibular distance, and the anterior translation distance. Measurements were taken on the injured side and the uninjured side and compared between the groups on postoperative axial CT scans.
Results: A total of thirty-six patients in both centers met our inclusion criteria and were included in the data analysis. Despite utilization of the Iso-C(3D), a high rate of malreductions was noted in both groups. Anterior translation distance malreductions occurred in 31% of the sixteen patients in Center A and 25% of the twenty patients in Center B (p = 0.72). The number of anterior fibular distance malreductions was similar, with a rate of 38% in Center A and 30% in Center B (p = 0.73). A significant difference among the centers (p = 0.03) was noted, however, when the posterior fibular distance data was analyzed, with 6% being malreduced by >2 mm in Center A and 40% in Center B.
Conclusions: The results of our study support previous investigations that have cited high rates of syndesmotic malreductions and demonstrate that the addition of advanced intraoperative imaging techniques does not help to reduce the rate of malreductions in this cohort.