Prospective validation and head-to-head comparison of 3 ankle rules in a pediatric population.

STUDY OBJECTIVE: The Ottawa Ankle Rules, Low-Risk Exam, and Malleolar Zone Algorithm are assessment rules designed to minimize radiographs performed on children with ankle trauma. We aim to determine the criterion validity of the abovementioned 3 rules for predicting clinically important ankle fractures in children.

METHODS: This was a prospective cohort study performed in a pediatric emergency department. Children aged 16 years and younger and with acute ankle trauma were eligible. Physicians were initially trained to assess patients according to the Ottawa Ankle Rules, Low-Risk Exam, and Malleolar Zone Algorithm. Furthermore, they implemented each rule with a standardized diagram. Radiography and referral to orthopedics were left to the physicians' discretion. The primary outcome was the confirmation of a clinically important fracture confirmed during the orthopedic follow-up. Patients who did not require orthopedic follow-up were contacted by telephone.

RESULTS: Radiography was performed for 245 of the 272 participants. All patients with no radiograph were reached by telephone. Forty-seven participants had a clinically important fracture. The sensitivity and specificity of the rules were 1.00 (95% confidence interval [CI] 0.93 to 1.00) and 0.27 (95% CI 0.21 to 0.33) for the Ottawa Ankle Rules, 0.87 (95% CI 0.75 to 0.94) and 0.54 (95% CI 0.47 to 0.60) for the Low-Risk Exam, and 0.94 (95% CI 0.83 to 0.98) and 0.24 (95% CI 0.19 to 0.31) for the Malleolar Zone Algorithm.

CONCLUSION: The Ottawa Ankle Rules identified all children with a clinically important fracture, whereas the Low-Risk Exam and the Malleolar Zone Algorithm showed lower sensitivities. The Low-Risk Exam showed the best specificity for clinically important fractures, decreasing the need for radiograph by 49%, but had missed 6 important fractures.