Syndesmotic Fixation in Supination-external Rotation Ankle Fractures: a Prospective Randomized Study

Background: This study compared mid-term functional and radiologic results of syndesmotic transfixation with no fixation in supination external rotation (SER) ankle fractures with intraoperatively confirmed syndesmosis disruption. Our hypothesis was that early-stage good functional results would remain and unfixed syndesmosis disruption in SER IV ankle fractures would not lead to an increased incidence of osteoarthritis.

Methods: A prospective study of 140 operatively treated patients with Lauge-Hansen SER IV (Weber B) ankle fractures was performed. After bony fixation, the 7.5-Nm standardized external rotation stress test for both ankles was performed under fluoroscopy. A positive stress examination was defined as a difference of more than 2 mm side-to-side in the tibiotalar or tibiofibular clear spaces on mortise radiographs. The patients were randomized to either syndesmotic screw fixation (13 patients) or no syndesmotic fixation (11 patients). After a minimum of 4 years of follow-up (mean, 58 months), ankle function and pain (Olerud-Molander, a 100-mm visual analogue scale [VAS] for ankle function and pain) and quality of life (RAND-36) of all 24 patients were assessed. Ankle joint congruity and osteoarthritis were assessed using mortise and lateral projection plain weight-bearing radiographs and magnetic resonance imaging (MRI; 3T) scans.

Results: Improvement in Olerud-Molander score, VAS, and RAND-36 showed no significant difference between groups during the follow-up. In the syndesmotic transfixation group, improvements in all functional parameters and pain measurements were not significant, whereas in the group without syndesmotic fixation, the Olerud-Molander score improved from 84 to 93 (P = .007) and the pain (VAS) score improved from 11 to 4 (P = .038) from 1 year to last follow-up. X-ray or MRI imaging showed no difference between groups at the last follow-up visit.

Conclusion: With the numbers available, no significant difference in functional outcome or radiologic findings could be detected between syndesmosis transfixation and no-fixation patients with SER IV ankle fracture after a minimum of 4 years of follow-up.

Level Of Evidence: Level II, prospective comparative study.