The Ottawa Ankle Rules in Asia: validating a clinical decision rule for requesting X-rays in twisting ankle and foot injuries

This was a study to determine if the Ottawa Ankle Rules (OAR) for requesting x-ray studies in twisting ankle and foot injuries are applicable in our Asian population. Four hundred ninety-four consecutive eligible patients presenting to the emergency department with twisting injuries about the ankle were examined by emergency physicians for clinical criteria requiring ankle and foot x-ray studies according to the OAR. Four hundred eighty-eight of these patients underwent x-ray studies that were interpreted by a radiologist. The sensitivity and specificity of the OAR for predicting the presence of fracture were calculated to be 0.9 and 0.34, respectively. When the rules were modified to cast a wider screening net, sensitivity improved to 0.99. We conclude that the OAR are not applicable to our population because of inadequate sensitivity, but when modified become acceptable and can reduce the number of x-ray studies requested by 28%.