This prospective randomised trial aimed to assess the superiority of internal fixation of well-reduced medial malleolar fractures (displacement □2mm) compared with non-fixation, following fibular stabilisation in patients undergoing surgical management of a closed unstable ankle fracture.

A total of 154 adult patients with a bi- or trimalleolar fracture were recruited from a single centre. Open injuries and vertically unstable medial malleolar fractures were excluded. Following fibular stabilisation, patients were randomised intra-operatively on a 1:1 basis to fixation or non-fixation after satisfactory fluoroscopic fracture reduction was confirmed. The primary outcome was the Olerud Molander Ankle Score (OMAS) at 12 months post-randomisation. Complications were documented over the follow-up period.

The baseline group demographics and injury characteristics were comparable. There were 144 patients reviewed at the primary outcome point (94%). The median OMAS was 80 (IQR, 60-90) in the fixation group vs. 72.5 (IQR, 55-90) in the non-fixation group (p=0.165). Complication rates were comparable, although significantly more patients (n=13, 20%) in the non-fixation group developed a radiographic non-union (p<0.001). The majority (n=8/13) were asymptomatic, with one patient requiring surgical reintervention. In the non-fixation group, a superior outcome was associated with an anatomical medial malleolar fracture reduction.

Internal fixation is not superior to non-fixation of well-reduced medial malleolar fractures when managing unstable ankle fractures. However, one in five patients following non-fixation developed a radiographic non-union and whilst the re-intervention rate to manage this was low, the longer-term consequences of this are unknown. The results of this trial may support selective non-fixation of anatomically reduced fractures.