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Immobilisation of stable ankle fractures

Three Part Question

In [adults and children with low risk distal fibular fractures] is [a functional brace better than plaster cast immobilisation] at [improving functionality and reducing time to recovery]

Clinical Scenario

A young, independently mobile female attends the Emergency Department following a fall. X-ray reveals a Weber A fracture of the lateral malleolus. She is reluctant to have a plaster cast and you wonder if a removable functional brace would be as effective

Search Strategy

Medline 1946 to February Week 4 using the OVID interface
([exp Fractures, bone/] AND [exp Ankle injuries/] AND [exp Orthotic devices/ OR exp Braces/ OR exp Casts, surgical/ OR OR OR]) LIMIT to human and English language

Search Outcome

260 papers found of which 5 were useful

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Stuart et al
40 adult patients with supination-eversiontype II fractures. Random allocation to below knee walking plaster or AirCast brace Prospective randomised studyComfort at 24hrsBrace better than cast (p<0.05)Small sample size.
Post fracture swellingBrace better than cast (p<0.00001)
Time to unionNo significant difference
Movement at unionBrace better than cast (p<0.00001)
Symptoms at 3 monthsBrace better than cast (p<0.05)
Port et al,
65 adult patients with stable lateral maleolus (Weber B1) fractures. Assigned to below knee plaster or elasticated support by treating orthopaedic surgeon Prospective observational studyPain (visual analogue score)No significant difference (0.6 ±0.4 in support vs 1.6 ±0.4 in plaster)No randomisation or blinding of allocation. All patients spent the 1st 24hrs in below knee cast from ED. No intention to treat analysis. Large female predisposition to treatment in plaster.
Function at 1 month60 in support vs 50 in plaster (p<0.001)
Function at 2 month80 in support vs 70 in plaster (p<0.01)
Function at 3 month89 in support vs 77 in plaster (p<0.05)
Function at 6 month93 in support vs 89 in plaster (No significant difference)
Boutis et al,
111 children aged 5 to 15 with acute symptomatic low risk ankle fracture. Randomised to receive fibreglass cast or AirCast brace Single blind, noninferiority RCTFunction at 4 months91.3% in brace vs 85.3% in plaster (p<0.0001)All patients kept non-weight bearing for 1st 5 days. Salter-Harris type I fractures included based on clinical findings alone.
Patient satisfaction52.8% in brace vs 18% in plaster ‘very satisfied’ (p<0.0001)
Cost effectivenessBrace cheaper than cast (p<0.0001, cost effectiveness accebtibility curve >80%)
Mason et al,
117 patients with metatarsal or stable ankle fracture and able to weight-bear. Assigned to treatment with fibreglass cast or AirCast brace Observational studyAbility to weight-bear at 48hrs65.85% in brace vs 42.48% in plaster (p<0.001)No blinding or randomisation (choice based on clinician preference). No evaluation of significance of results or follow up
Barnett et al,
45 children aged 5 to 15 with acute symptomatic low risk ankle fracture. Randomised to receive fibreglass posterior splint or AirCast brace Single blind, noninferiority RCTFunction at baselineNo significant difference (p=0.39)Underpowered due to poor recruitment and small sample size.
Function at 2 weeksNo significant difference (p=0.26)
Function at 4 weeksNo significant difference (p=0.13)


5 studies of varying quality build on the existing evidence base that using a functional brace postoperatively in ankle fractures to support the use of such devices in stable Weber A or B1 ankle fractures. The findings show that a functional brace is at least as good as, if not better than, immobilisation in plaster in all measured outcomes.

Editor Comment

ED, emergency department; RCT, randomised controlled trial.

Clinical Bottom Line

The currently available evidence is based on small numbers and observational studies, but a functional brace is shown to give more favourable outcomes and should be considered on an individual basis. Larger studies of good quality are needed to answer this specific question.


  1. Stuart P R, Brumby C, Smith S R. Comparative study of functional bracing and plaster cast treatment of stable lateral malleolar fractures. Injury 1989; 20: 323-6.
  2. Port A M, McVie J L, Naylor G et al. Comparison of two conservative methods of treating an isolated fracture of the lateral malleolus. J Bone Joint Surg Br 1996; 78: 568-72.
  3. Boutis K, Willan A R, Babyn P, et al. A randomised, controlled trial of a removable brace versus casting in children with low-risk ankle fractures. Pediatrics 2007; 119: e1256-63.
  4. Mason L W, Dodds A. A prospective study comparing attempted weight bearing in fibreglass below-knee casts and prefabricated pneumatic braces. Foot Ankle Spec 2010; 3: 64-6.
  5. Barnett P L J, Lee M H, Oh L, et al. Functional outcome after air-stirrup ankle brace or fibreglass backslab for pediatric low-risk fractures. Pediatr Emerg Care 2012 Aug; 28(8): 745-9.