AIR trial (cast vs removable brace)

Use of cast immobilisation versus removable brace in adults with an ankle fracture: multicentre randomised controlled trial.

Kearney R, McKeown R, Parsons H, et al. BMJ (Clinical research ed.) 2021 · PMID 34226192 · doi:10.1136/bmj.n1506

Question

After an ankle fracture, does a removable brace with early movement give better function than immobilisation in a plaster cast?

Design

Pragmatic multicentre RCT in UK NHS trauma units.

Patients

Adults with an acute ankle fracture suitable for cast immobilisation.

Intervention

Removable brace with early ankle exercises

Comparison

Below-knee plaster cast

Primary outcome

Olerud-Molander Ankle Score (OMAS) at 16 weeks

Key result

There was no statistically significant or clinically important difference in OMAS at 16 weeks between brace and cast, nor in secondary analyses.

Limitations

Unblinded; adherence to brace removal and exercise regimens varied, and the population was heterogeneous (operative and non-operative fractures).

Impact on practice

Either a cast or a removable brace is acceptable after ankle fracture, so the choice can be guided by patient preference, cost and local resources.