9.13 Ankle Sprain
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agk's Library of Common Simple Emergencies

Presentation
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The patient inverted the foot and either came 
in immediately or a day later with pain, 
swelling, and inability to walk. There is 
tenderness to palpation of the anterior 
talofibular ligament (anterior to the lateral 
malleolus) and on stretching of the ATFL with 
supination or pulling the talus anteriorly 
(drawer sign).

What to do:
-----------

- If the patient is not already doing this, 
    elevate the foot and apply ice 15 minutes 
    per hour to treat the reactive 
    inflammation.
- Document the mechanism of injury, previous 
    injuries, deformity, swelling, discolor- 
    ation, circulation, sensation, movement.
- Palpate the prominence on the lateral foot 
    that is the base of the fifth metatarsal, 
    where the insertion of the peroneus brevis 
    can be avulsed by an inversion injury, and 
    which may be better seen on foot views.
- Palpate the fibula on the lateral leg up to 
    the knee, where spiral fractures can 
    propagate when the ankle breaks, and which 
    also do not show on standard ankle views.
- If there is tenderness posterior to the 
    lateral malleolus or the patient cannot 
    take four steps in the ED, obtain ankle x- 
    rays to rule out a fracture. Films 
    otherwise are optional and can be deferred.
- Immobilize the ankle in a stirrup (or 
    sugar-tong) splint. Provide the patient 
    with crutches for 3-4 days, anti- 
    inflammatory analgesics, and follow up.

What not to do:
---------------

- Do not rule out a fracture based on a 
    negative x-ray. 
- Do not overlook fractures of the tarsal 
    navicular, talus, or os trigonum, all 
    visible on the ankle view.

Discussion
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Although patients continue to visit EDs with 
ankle sprains, our role remains to rule out 
other injuries, and teach them how to care for 
themselves. Patients ask if a bone is broken, 
but the initial treatment is usually the same 
regardless of the x-ray results. Most ankle 
sprains could be managed over the telephone, 
and seen in the office the next day.

References:
-----------

- Stiell IG, Greenberg GH, McKnight RD, Nair 
    RC, McDowell I, Reardon M, Stewart JP, 
    Maloney J: Decision rules for the use of 
    radiography in acute ankle injuries: 
    refinement and prospective validation. *J 
    Am Med Assn* 1993;269:1127-1132.
- Halvorson G, Iserson KV: Comparison of four 
    ankle splint designs. *Ann Emerg Med* 
    1987;16:1249-1252.

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