The Ottawa Ankle Rules

If you have been in practice for any length of time, you have had a patient limp in with ankle pain. Simple sprains are often simple to address and treat, but when there is considerable swelling and pain, the question of fracture must be raised. Standards of care dictate that most patients with ankle injuries are X-rayed; statistically, however, only about 15 percent of these X-rays are positive for fracture.

The Ottawa Ankle Rules, developed by a team at one of the departments of emergency medicine in Ottawa, Canada, and so named by their creators a few years after their development, are a set of guidelines to help doctors determine whether a patient with foot or ankle pain should be offered X-rays to diagnose a possible bone fracture.

Of course, get a history of the injury and perform your clinical assessment of the injured ankle first. More severe ankle sprains will demonstrate considerable pain and swelling, so extensive palpation and goading of the joint is not often possible. The following guidelines will serve to help you determine the appropriateness of ordering radiographic studies:

• Obtain an ankle X-ray if there is pain near the malleoli and one of the following: bone tenderness at the posterior edge of the distal 6 cm or the tip of either malleolus; or the patient is unable to bear weight for at least four steps immediately after the injury and at the time of evaluation.
• Obtain a foot X-ray if there is pain in the midfoot and one of the following: bone tenderness at the navicular or the base of the fifth metatarsal; or the patient is unable to bear weight for at least four steps immediately after the injury and at the time of evaluation.

Given the expense of diagnostic studies, many patients are hesitant to pursue radiographs if they are not completely covered by their insurance. These rules provide a clear rationale as to when radiographs are indicated and have been well-researched and statistically validated. However, if you have any concern about the possibility of a fracture, certainly pursue diagnostic studies. Also, I personally refer all grade III sprains for further orthopedic assessment. In the absence of fracture, pursue appropriate care: rest, ice and taping, wrapping or splinting as indicated.

As always, clearly document your findings and the rationale for your care plan. If you choose to (or not to) perform radiographs, make sure to reference the above guidelines as part of your clinical thought process. For more information, type "Ottawa Ankle Rules" into your favorite search engine. There are quite a number of studies, graphics, and references readily available online.

Resources

1. Wikipedia explanation of the Ottawa Ankle Rules. http://en.wikipedia.org/wiki/Ottawa_ankle_rules
2. Kilgore DB. "Primary Care Treatment of Ankle Fractures." http://tacomafamilymedicine.org/tfm/secure/lectures/orthopedics/AnkleFx2.pdf
3. Ottawa Ankle Rule. www.mssm.edu/medicine/general-medicine/ebm/CPR/Ottawa.html