A new intraoperative classification of distal tibiofibular syndesmosis injury and internal fixation

Abstract

Objective To investigate the guidance of a new intraoperative classification of distal tibiofibular syndesmosis injury in the selection of internal fixation for ankle fractures. Methods Between January 2010 and January 2015 our department treated 116 patients with displaced closed ankle fracture (Weber type B or C). They were 60 men and 56 women, aged from 18 to 78 years (average, 45.6 years). After reduction and fixation of the fibular fracture, we assessed the syndesmosis stability using the fibular hook traction test and radiological findings. We classified the distal tibiofibular syndesmosis injury into 3 grades (grade Ⅰ: 7 mm displacement). Se-lection of proper screwing was determined by our new classification. Results Of the 116 cases, 82 (70.7%) demonstrated distal tibiofibular syndesmosis injury. Screwing of the distal tibiofibular syndesmosis was not conducted for 30 (25.9%) of them who were of stable grade Ⅰ. 52 (44.8%) cases were of unstable grades Ⅱ and Ⅲ. Of the 48 cases of grade Ⅱ, 44 were fixated with one screw and the rest 4 became stable grade Ⅰ after Volkmann block fixation and received no screwing. Fixation of the distal tibiofibular syndesmosis with 2 screws was conducted for the 4 cases of unstable grade Ⅲ. All the patients were followed up for 12 to 60 months. No non-union, screw breakage, or syndesmosis separation after screw removal occurred. The American Orthopaedic Foot and Ankle Society ankle-hindfoot scoring showed a good/excellent rate of 93.1% (108/116) . Conclusion Our new intraoperative classification can provide correct judgment of the severity of distal tibiofibular syndesmosis injury, thus guiding the selection of proper screw fixation to enhance the outcomes of ankle fractures. Key words: Ankle joint; Fractures, bone; Fracture fixation, internal; Distal tibiofibular syndesmosis; Classification