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Functional brace vs walking boot in management of severe lateral ankle sprains

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Functional brace vs walking boot in management of severe lateral ankle sprains

Vol: 3| Issue: 5| Number:38| ISSN#: 2564-2537
Study Type:Therapy
OE Level Evidence:2
Journal Level of Evidence:N/A

A comparative, prospective, and randomized study of two conservative treatment protocols for first-episode lateral ankle ligament injuries

Foot Ankle Int. 2014 Mar;35(3):201-6

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186 patients with a severe lateral ankle sprain (type III) were randomized to treatment to 3 weeks of rigid immobilization with a walking boot followed by 3 weeks of immobilization with a functional brace, or to a functional brace for 6 weeks. The purpose was to compare these two conservative treatment methods for outcomes in pain, function, and ankle stability up to 12 weeks after the injury. AOFAS scores were better for the first 6 weeks in patients receiving the functional brace, and pain and comfort outcomes also benefited within the first few weeks from using a functional brace. By 12 weeks, ankle stability was re-established effectively and similarly between the two groups.

Publication Funding Details +
None disclosed

Risk of Bias


Reporting Criteria


Fragility Index


Was the allocation sequence adequately generated?

Was allocation adequately concealed?

Blinding Treatment Providers: Was knowledge of the allocated interventions adequately prevented?

Blinding Outcome Assessors: Was knowledge of the allocated interventions adequately prevented?

Blinding Patients: Was knowledge of the allocated interventions adequately prevented?

Was loss to follow-up (missing outcome data) infrequent?

Are reports of the study free of suggestion of selective outcome reporting?

Were outcomes objective, patient-important and assessed in a manner to limit bias (ie. duplicate assessors, Independent assessors)?

Was the sample size sufficiently large to assure a balance of prognosis and sufficiently large number of outcome events?

Was investigator expertise/experience with both treatment and control techniques likely the same (ie.were criteria for surgeon participation/expertise provided)?

Yes = 1

Uncertain = 0.5

Not Relevant = 0

No = 0

The Reporting Criteria Assessment evaluates the transparency with which authors report the methodological and trial characteristics of the trial within the publication. The assessment is divided into five categories which are presented below.




Outcome Measurements


Inclusion / Exclusion


Therapy Description



Detsky AS, Naylor CD, O'Rourke K, McGeer AJ, L'Abbé KA. J Clin Epidemiol. 1992;45:255-65

The Fragility Index is a tool that aids in the interpretation of significant findings, providing a measure of strength for a result. The Fragility Index represents the number of consecutive events that need to be added to a dichotomous outcome to make the finding no longer significant. A small number represents a weaker finding and a large number represents a stronger finding.

Why was this study needed now?

Despite lateral ankle sprains causing ligament ruptures being one of the most prevalent presentations in either the emergency room or orthopaedic office, debate among practitioners and residents still exists on both classification of the injury and the most effective means to treat it. Traditionally, injuries of this nature have been treated using rigid immobilization for 3 weeks, subsequently followed by protection using a functional brace for another 3 weeks. However, there has been growing interest in whether using a functional brace initially, and foregoing rigid immobilization, may provide patients with earlier functional return and comparably good final results.

What was the principal research question?

How do two conservative treatment methods - rigid immobilization for 3 weeks followed by functional brace immobilization for 3 weeks, or functional brace use only - compare, with respect to pain intensity, function, recovery and instability following a severe lateral ankle sprain?

Study Characteristics -
186 patients (aged 15-65; 104 males) with a first-episode lateral ankle ligament injury (at least 1 complete ligament rupture) of type III severity (gross instability) were included. Those with cases of previous severe lateral ankle sprains were excluded.
Group A: Patients initially received rigid immobilization with a walking boot (Robofoot) for 3 weeks, followed by immobilization with a functional brace (AIRCAST ankle sport brace) for 3 more weeks. Weight bearing as tolerated was allowed for the first 3 weeks. Rehabilitation began at 4 weeks, consisting of strengthening and proprioception exercises, limiting ankle inversion, and plantar flexion to 10 degrees.
Group B: Patients received the functional brace from the initiation of treatment. Weight bearing and rehabilitation were the same as previously described above.
Outcomes included pain on a visual analog scale (VAS), clinical general status, and the American Orthopaedic Foot and Ankle Surgeons (AOFAS) score. Radiographic evaluation also consisted of X-rays in the anteroposterior view with varus stress and in the lateral view with the anterior drawer test.
RCT; Prospective
Clinical evaluation was conducted during follow-up at 1, 3, 6, and 12 weeks. Radiographic evaluation performed at the 12 week follow-up.

What were the important findings?

  • At 1 week, no significant differences were noted between groups in edema intensity, average VAS pain, or weight-bearing capacity. A significant difference in comfortability (p=0.029) and AOFAS scores (p=0.00003) was noted between groups, both favouring Group B.
  • Irrespective of group allocation, AOFAS score at 1 week were lower among participants with 3 ligamentous lesions.
  • At 3 weeks, groups did not significantly differ in either pain location or weight-bearing capacity. At this time point, AOFAS scores remained significantly higher in Group B (84.8 +/- 8.8 vs. 79.5 +/- 9.2; p=0.00004), and patients of Group B had missed fewer days from work (3.9 +/- 2.7 vs. 7.0 +/- 3.8; p<0.01). Pain intensity at 3 weeks did not clinically differ between groups (Group A 1.7 +/- 1.2; Group B 1.4 +/- 1.2).
  • At 6 weeks, the only significant difference that was noted between groups was a higher AOFAS in Group B (94.3 +/- 6.6 vs. 90.5 +/- 10.6; p=0.027). Anterior drawer tests were normal in all patients but 1 at 6 weeks.
  • At 12 weeks, no significant differences were observed between groups. At this time, articular stability was assessed using varus stress and anterior drawer stress X-rays, with no differences noted between contralateral and affected sides.

What should I remember most?

Treatment of a lateral ankle sprain with a functional brace was associated with increased comfort over the first 3 weeks and slightly better functional outcome over 6 weeks when compared to treatment with a walking boot followed by a functional brace. Both treatment methods resulted in restoration of normal ankle stability within 6 weeks. Short-term functional outcome of extensive ligament injuries (three injured ligaments) was lower than less severe injuries, regardless of allocated treatment.

How will this affect the care of my patients?

Either treatment method included in this study appears to effectively re-establish ankle stability following a type III lateral ankle sprain characterized by gross instability. Immobilization with a functional brace from the initiation of treatment appears to confer similar efficacy to rigid immobilization with a walking boot, and may even be more comfortable for patients. Short-term pain and function also somewhat benefited with the functional brace. The long term stability implications of these two treatment methods should be determined.

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