Validation of the Ottawa ankle rules in a second-level trauma center in Italy

Abstract

Trauma of the foot and ankle is commonly seen in the emergency unit. Nearly all of these patients undergo radiography even though only approximately 15% have clinically significant fractures. The Ottawa ankle rules (OARs) have been designed to reduce the number of unnecessary radiographs ordered for these patients. The objective of this study was to validate the OARs in a Italian trauma center. This prospective study enrolled 248 patients with acute ankle injury from July to October 2006 in the Ospedali Riuniti emergency department. Main outcome measures were: sensitivity, specificity, positive predictive value, negative predictive value, and likelihood ratios (positive and negative) of the OARs. Sensitivity of the OARs for detecting 42 ankle fractures (29 in the malleolar zone, 4 in the midfoot zone and 4 concomitant in both zones) was 100% for each of the two zones and for both zones. Specificity of the OARs for detecting fractures was 46.5% for both zones, 43.5% for the malleolar zone, and 41.0% for the midfoot zone. Implementation of the OARs had the potential for reducing radiographs by 29%. OARs are highly sensitive tools for detecting ankle and midfoot fractures. Implementation of these rules would reduce the number of radiographs and the associated costs, radiation exposure and waiting times in emergency departments.