Prospective Evaluation of the Ottawa Ankle Rules in a University Sports Medicine Center

Abstract & Commentary

Synopsis: Use of the Ottawa Ankle Rules could limit the need for x-rays in patients without increasing the risk of missing a significant ankle injury.

Source: Leddy JJ, et al. Prospective evaluation of the Ottawa Ankle Rules in a university sports medicine center. Am J Sports Med 1998;26(2):158-165.

In an attempt to develop a clinical decision rule to screen emergency room patients, Stiell and colleagues1 developed a set of clinical evaluation guidelines for patients who present with an acute ankle injury. Using their "Ottawa Ankle Rules," they were able to limit the frequency of x-rays taken in the emergency department without increasing the risk of missing a significant ankle injury. The current study was designed to evaluate the effectiveness of the Ottawa Ankle Rules in a university sports medicine center, where the predicted incidence of a clinically significant fracture is lower (about 8%) than in an emergency department (where it is 13-20%). Leddy and colleagues evaluated all persons (children and adults) who presented to their office with an acute ankle or midfoot injury. The only individuals excluded were those with injuries more than 10 days old, an obviously deformed ankle or foot, or altered sensorium, or an individual who returned for a second evaluation for the same injury.

The evaluating physicians were instructed in the use of the "Ottawa Ankle Rules," which require radiography of the ankle if, and only if, there is bony tenderness along the last 6 cm of the posterior aspect of the medial or lateral malleolus or tenderness to palpation over the base of the fifth metatarsal or over the tarsal navicular or if there is inability to bear weight both immediately after injury and during the examination (four steps, regardless of limping). When none of these signs is present, x-rays are not obtained. When any one sign was present, x-rays were taken.

Two hundred ten patients were enrolled in the study. Eleven clinically significant fractures (8.3%) were identified. Application of the Ottawa Ankle Rules was 100% sensitive in identifying these significant ankle fractures, and Leddy et al conclude that use of the "Ottawa Ankle Rules" could significantly reduce the need for radiography in patients with acute ankle and midfoot injuries in this setting (ambulatory sports medicine clinic) without missing clinically significant fractures.

Comment by James D. Heckman, MD

Ankle injuries are the most common reason for lost time from participation in athletic activities. In a busy sports medicine practice, a clinical decision rule that can be applied with 100% sensitivity can be used to improve the cost-effectiveness of the practice. The authors in this study and in the emergency room studies previously reported have found the rules both easy to use and valid. They are a cost-effective screening tool that can be used to identify those ankle injuries that are not associated with a significant fracture and, thus, can be treated effectively with rest, ice, compression, and elevation. In this series of 210 patients, Leddy et al were able to forego ankle x-rays in 34% of the patients who presented with an acute injury without missing any clinically significant fractures. It should be pointed out that these rules should be applied only to acute injuries (those less than 10 days old) and, thus, do not apply to chronic or repeat ankle injuries. The patients must be able to comply and so must be alert and cooperative with the examination. One of the critical phases of the evaluation is a weight-bearing test. Leddy et al found that while many patients were reluctant to try to put weight on the affected ankle, with some gentle encouragement they were often able to do so. Clinical decision rules, such as the Ottawa Ankle Rules, can facilitate our medical decision-making and can conserve important resources without compromising the care of our patient athletes.

Reference

1. Stiell IG, et al. A study to develop clinical decision rules for the use of radiography in acute ankle injuries. Ann Emerg Med 1992;21(4):384-390.