AIR trial

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

For adults with an ankle fracture treated with immobilisation, is a removable brace non-inferior to a plaster cast?

Design

Pragmatic multicentre RCT in UK NHS trauma units.

Patients

Adults with an acute ankle fracture judged suitable for below-knee cast immobilisation.

Intervention

Removable brace with immediate ankle range-of-movement exercises

Comparison

Below-knee plaster cast, with exercises started after cast removal

Primary outcome

Olerud-Molander Ankle Score at 16 weeks

Key result

There was no significant difference in ankle function at 16 weeks between cast and brace, and no clinically important differences at other time points; casting was not superior to functional bracing.

Limitations

Patients and clinicians were not blinded, and a notable minority did not complete follow-up.

Impact on practice

Supports offering a removable brace rather than a cast after ankle fracture, allowing earlier ankle movement and hygiene with fewer clinic and plaster room visits.