Validation of the Ottawa ankle rules in children with ankle injuries

Objectives: The Ottawa Ankle Rules (OAR) have been found to be 100% sensitive in adult patients with ankle injuries, and application of the OAR has resulted in, a 28% reduction in the number of x-rays ordered. The objectives of this study were to determine the sensitivity and specificity of the OAR in children and to determine the potential change in x-ray utilization. Methods: Children, aged 2-16 years, presenting to the EDs of two children's hospitals, with an ankle injury in the previous 48 hours, were enrolled. All patients were assessed by either staff physicians or fellows. X-rays were ordered according to standard clinical practice. Prior to reviewing x-rays, the physical examination was recorded on a standardized form. Positive outcomes (clinically significant) were defined as fractures with fragments greater than or equal to 3 mm. Patients not x-rayed and asymptomatic at five to seven days postinjury were considered to have no significant fracture. Results: Six hundred seventy patients were enrolled. The OAR were 100% sensitive (95% CI = 95% to 100%) for significant ankle fractures, with a specificity of 24% (95% CI = 20% to 28%). The OAR were 100% sensitive (95% CI = 82% to 100%) for the midfoot, with a specificity of 36% (95% CI = 29% to 43%). If the OAR had been followed, there would have been a reduction of ankle x-rays by 16% and foot x-rays by 29% without missing any clinically significant fracture. However, analysis of the two hospitals showed that if the rules had been applied, one would have a reduction in x-rays, while the other center would have an increase. Conclusions: This study demonstrates the OAR to be sensitive for detecting clinically significant (greater than or equal to 3 mm) ankle and midfoot fractures in children. The application of these rules may reduce the number of x-rays ordered. A further study is required to determine the effect of using the OAR in clinical practice.