PROSPECTIVE EVALUATION OF THE OTTAWA ANKLE RULES IN A UNIVERSITY SPORTS MEDICINE CENTER - WITH A MODIFICATION TO INCREASE SPECIFICITY FOR IDENTIFYING MALLEOLAR FRACTURES

In a sports medicine center, we prospectively evaluated the Ottawa Ank le Rules over 1 year for their ability to identify clinically signific ant ankle and midfoot fractures and to reduce the need for radiography . We also developed a modification to improve specificity for malleola r fracture identification. Patients with acute ankle injuries (less th an or equal to 10 days old) had the rules applied and then had radiogr aphs taken. Sensitivity, specificity, and the potential reduction in t he use of radiography were calculated for the Ottawa Ankle Rules in 13 2 patients and for the new ''Buffalo'' rule in 78 of these patients. T here were 11 clinically significant fractures (fracture rate, 8.3% per year). In these 132 patients, the Ottawa Ankle Rules would have reduc ed the need for radiography by 34%, without any fractures being missed (sensitivity 100%, specificity 37%). In 78 patients, the specificity for malleolar fracture for the new rule was significantly greater than that of the Ottawa Ankle Rules malleolar rule (59% versus 42%), sensi tivity remained 100%, and the potential reduction in the need for radi ography (54%) was significantly greater. The Ottawa Ankle Rules could significantly reduce the need for radiography in patients with acute a nkle and midfoot injuries in this setting without missing clinically s ignificant fractures. The Buffalo modification could improve specifici ty for malleolar fractures without sacrificing sensitivity and could s ignificantly reduce the need for radiography.