Sensitivity of the Ottawa rules.

STUDY OBJECTIVE: To validate criteria predicting ankle and mid-foot fractures with 100% sensitivity.

DESIGN: Prospective validation study

SETTING: A 929-bed community teaching hospital with an annual census of 76,488 ED visits.

PARTICIPANTS: Convenience sample of patients older than 18 years with acute ankle or midfoot injury.

INTERVENTIONS: Radiography was performed in each patient received after pertinent history and physical examination findings were recorded.

RESULTS: Five hundred seventy radiographs were obtained in 484 patients. Four hundred twenty-one were of the ankle, and 149 were of the foot. There were 93 ankle fractures and 29 midfoot fractures, giving a fracture yield of 22.1% for ankle films and 19.5% for foot films. Decision rules had sensitivity of 94.6% and specificity of 15.5% for ankle fractures and sensitivity of 93.1% and specificity of 11.5% for midfoot fractures. Prospective criteria failed to predict fracture in five of the ankle group and two of the midfoot group. Physicians predicting fracture solely on the basis of clinical suspicion had a sensitivity of 69% in ankle injuries and 76% in midfoot injuries.

CONCLUSION: We were unable to validate with 100% sensitivity the Ottawa rules predicting ankle and midfoot fractures. However, the Ottawa rules were more sensitive than clinical suspicion alone.