SUPER-FIN

Is cast immobilisation inferior to surgery for the treatment of unimalleolar Weber B ankle fractures with a congruent mortise on initial radiography but deemed unstable by external rotation stress testing?

Project timeline

Study design

Randomised, pragmatic, non-inferiority, clinical trial

Status

Finished

This study was carried out from 16 January 2013 to 7 July 2021 where 840 skeletally mature patients (age ≥16 years) with an isolated Weber B fibula fracture on static radiographs were recruited. Fracture instability was assessed by standard external rotation stress test under fluoroscopy. 714 participants were excluded (569 with stable fracture, mortise incongruency, or fracture dislocation).

The remaining 126 patients with a congruent but unstable ankle mortise were randomised to receive either conventional cast immobilisation for six weeks (n=62) or surgical treatment with open reduction and internal plate fixation followed by cast immobilisation for six weeks (n=64).

One hundred and twenty-one out of 126 randomised participants (96%) completed the study. In the primary intention-to-treat analysis of 121 participants completing two year follow-up, the mean OMAS was 89 in the cast immobilisation group and 87 in the surgery group (between group mean difference 1.3 points, 95% confidence interval −4.8 to 7.3). No statistically significant between group differences were observed in any secondary outcomes. One participant in each group had radiographic evidence of non-union. In the surgery group, one participant had a superficial wound infection, one had delayed wound healing, and nine underwent procedures to remove hardware, two of whom developed postoperative infections (one deep and one superficial).

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