What are Ottawa Ankle Rules?

The Ottawa ankle rules are a series of guidelines used by physicians when evaluating patients with foot and ankle pain to determine if X-rays are necessary. These guidelines were developed in Ottawa, Canada by a group of physicians who were concerned about unnecessary foot and ankle X-rays. Prior to the development of an accurate and sensitive screening method, most patients who presented with foot and ankle pain were X-rayed to check for fractures. Only a small percentage of these patients had fractures, making the X-rays a waste of resources, in addition to a health risk for patients.

Under the Ottawa ankle rules, if a patient has bone tenderness at the bony prominence of the ankle or the bottom of the tibia, the long bone in the front of the lower leg, it is an indicator that there may be a fracture. Likewise, if the patient cannot put weight on the foot or walk for more than four steps, there may be a fracture involved. This simple screen rarely results in false negatives and greatly reduces the number of ankle X-rays ordered for patients.

These rules also include screening guidelines for foot fractures. Patients who have bone tenderness in the midfoot cannot bear weight on the injured foot, or cannot walk for more than four steps are candidates for X-rays. The Ottawa ankle rules were later adapted to create a similar set of guidelines for the knee, known as the Ottawa knee rules.

Applying the Ottawa ankle rules has a number of advantages. Physicians who work in emergency rooms need to be able to quickly and accurately screen patients for major medical issues to ensure that these issues are caught, without ordering unnecessary tests. Ordering a patient to X-ray when it is not necessary generates additional costs, keeps the patient in the hospital longer, ties up the X-ray facility, and exposes the patient to risks, because every X-ray exposes a patient to radiation. The development of rules that could be used to exclude people who obviously did not have fractures made emergency rooms more efficient and improved the quality of patient care.

The Ottawa ankle rules are not applied in situations where it is clearly evident that a patient has a fracture. Open fractures of the ankle and foot, for example, are very easy to identify, and the patient can be sent immediately to X-ray to assess the fracture for the purpose of developing a treatment plan. Likewise, other tell-tale signs of a foot and ankle fracture like a physically impossible angle will lead a physician to skip the evaluation and order an X-ray.