Postoperative computed tomography-based control of syndesmotic screws

Purpose: Skeletal reconstruction and position of osteosynthetic devices, especially of the syndesmotic screws, were controlled postoperatively in order to check the accuracy of surgical intervention and of intraoperative C-arm control. Patients and Methods: This is a prospective, nonrandomized study of a closed series of 37 patients with ankle fractures AO type B and C who were treated according to the AO principles and in whom a syndesmotic screw was used. All patients underwent postoperative computed tomograpy. Results: Intraoperative radiography was judged to be normal by all surgeons. Retrospectively, it was considered to be abnormal in nine patients - verified by computed tomography in six-, normal in 22 patients, and technically imperfect in six. So, intraoperative radiography proved to be erroneous in nine patients (24.3%). Computed tomography revealed a less than perfect result in six of 37 patients (16.2%). In four patients this was due to pure anterior subluxation of the fibula. None of 13 patients who had a temporary Kirschner wire (K-wire) fixation of the fibula intraoperatively had a malposition, whereas six out of 24 patients (25%) without K-wire did show a malposition. A revision operation was carried out in five patients (13.5%). Conclusion: It can be stated, that the positioning of a syndesmotic screw is technically delicate, that intraoperative two-dimensional C-arm control is not sufficient to detect malpositions of the screw and/or the lateral malleolus, and that prior to screw placement temporary K-wire fixation of the fibula is mandatory. If plain radiography leaves any doubt about the quality of reduction, postoperative computed tomography is indicated. © Urban & Vogel.