Ankle Sprain

9.13 Ankle Sprain

Presentation
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, discoloration, 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
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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