Characteristics of and surgical strategies for distal tibiofibular syndesmosis separation based on ankle axial CT scan / 中华创伤骨科杂志

Objective To explore the clinical characteristics of and surgical strategies for distal tibiofibular syndesmosis separation based on ankle axial CT scan.Methods From January 2009 to January 2016,63 patients with injury to the distal tibiofibular syndesmosis were treated.Their injuries were characterized according to the anatomic characteristics on their ankle axial CT scan images as pronation-extorsion type (28 cases),supination-extorsion type (11 cases) and abduction type (24 cases).Specific strategies of reduction and fixation depended on the specific characteristics of distal tibiofibular syndesmosis separation.After 12 months postoperatively,the reduction quality was assessed by Burwell-Charnley's radiological evaluation system and the function of ankle joint was assessed using American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score system.Results The patients were followed up for 6 to 48 months (average,19.3 months).Anatomical reduction was achieved in 19 cases,good reduction in 7 and fair reduction in 2 in the pronation-extorsion type,yielding an excellent to good rate of 92.8％;anatomical reduction was achieved in 6 cases,good reduction in 4 and fair reduction in one in the supination-extorsion type,yielding an excellent to good rate of 90.9％;anatomical reduction was achieved in 17 cases,good reduction in 6 and fair reduction in one in the abduction type,yielding an excellent to good rate of 95.8％.By the AOFAS system,the pronation-extorsion type scored 88.6 points,the supination-extorsion type 89.4 points and the abduction type 86.6 points.Conclusion In the treatment of distal tibiofibular syndesmosis separation,reduction and fixation strategies should depend on analysis of the characteristics on the ankle axial CT scan,so as to achieve positive outcomes.

Diagnostic Landmarks of Ankle Syndesmosis Separation Measured on Standard Ankle Anterior - posterior Radiographs of Normal Korean Adults / 대한정형외과학회잡지

We performed standardized anterior-posterior radiographs of the normal ankle on 50 males and 50 females to determine the validity of current radiographic landmarks of the ankle syndesmosis separation. The average tibiofibular overlap was 6.9+/-2.1mm. The tibiofibular clear space was measured 4.1+/-0.9mm overall. The ratio of the tibiofibular overlap to the fibular width averaged 48+/-14%. Our data show that for 95% confidence intervals, the values for the syndesmosis separation are : (1) tibiofibular overlap less than 2.7mm, (2) tibiofibular clear space greater than 5.9mm, (3) tibiofibular overlap: fibular width ratio less than 24%. According to current diagnositc criterion of tibiofibular overlap under 10mm, 87% of this cohort was defined as syndesmosis separation. Other current criteria of tibiofibular clear space over 5 mm and tibiofibular overlap: fibular width ratio less than 24%, the false positivity was only 7% and 2%, respectively. Therefore the tibiofibular clear space and the tibiofibular overlap: fibular width ratio are more reliable diagnositc criteria for syndesmosis separation than the tibiofibular overlap.