No difference in functional and radiographic results 8.4 years after quadricortical compared with tricortical syndesmosis fixation in ankle fractures

Abstract

Objective: To assess long-term functional and radiologic results after two types of syndesmosis fixation, comparing one quadricortical syndesmotic screw fixation with two tricortical screw fixation in ankle fractures.

Design: Follow up of a previously conducted prospective, randomized clinical study.

Setting: University clinic, Level I trauma center.

Patients: Forty-eight patients with closed ankle fractures and concomitant syndesmotic rupture were operated on with quadricortical (n = 23) or tricortical (n = 25) syndesmotic fixation.

Results: Follow-up time was 8.4 years (range, 7.7-8.9 years). There were no statistical differences in the two groups regarding Olerud-Molander Ankle score, Orthopaedic Trauma Association score, or degree of osteoarthritis. Patients with a difference in the syndesmotic width between the operated and the nonoperated ankle of 1.5 mm or more showed a tendency toward poorer functional results (P = 0.056). Twenty-one patients showed synostosis on plain radiographs. Of these, only seven patients had synostosis verified on computed tomography, all of whom had significantly worse function. Patients with a posterior fracture fragment at time of operation had poorer Olerud-Molander Ankle score (73.1 versus 85, P = 0.05) and all had osteoarthritis as compared with 55% of those without a posterior fragment. Obese patients (body mass index greater than 30 kg/m2) also had poorer Orthopaedic Trauma Association score, but neither obesity nor being overweight predicted late arthritis.

Conclusions: Follow up 8.4 years after surgery of ankle fractures with syndesmotic injury showed satisfactory functional results with only minor differences between the two groups of syndesmotic fixation. Obese patients had significantly poorer functional results. The presence of a posterior fracture fragment was an important negative prognostic factor regarding functional results. Plain radiographs overestimated tibiofibular synostosis. Synostosis on computed tomography, however, predicted impaired ankle function. A difference in syndesmotic width 1.5 mm or greater between the two ankles seemed to be associated with an inferior clinical result.