Syndesmosis fixation in supination-external rotation ankle fractures. Long-Term results of a prospective randomised study.

Background: The clinical relevance and treatment of syndesmosis injury in supination-external rotation (SER) ankle fractures are controversial.

Methods: After malleolar fixation 24 SER 4 ankle fracture patients with unstable syndesmosis in external rotation stress test were randomised to syndesmosis transfixation with a screw (13 patients) or no fixation (11 patients). Mean follow-up time was 9.7 years (range, 8.9-11.0). The primary outcome measure was the Olerud-Molander Ankle Outcome Score (OMAS). Secondary outcome measures included ankle mortise congruity and degenerative osteoarthritis, 100-mm visual analogue scale for function and pain, RAND 36-Item Health Survey, and range of motion.

Results: Mean OMAS in the syndesmosis transfixation group was 87.3 (SD 15.5) and in the no-syndesmosis-fixation group 89.0 (SD 16.0) (difference between means 1.8, 95% CI -10.4-14.0, P = 0.76). There were no differences between the two groups in secondary outcome measures.

Conclusions: With the numbers available, SER 4 ankle fractures with unstable syndesmosis can be treated with malleolar fixation only, with good to excellent long-term functional outcome.