Validation of the Ottawa ankle rules at a tertiary teaching hospital

Abstract

Background: Ankle joint and foot injuries are among the most common injuries seen at the accident and emergency (A&E) department of any hospital. Radiographs are ordered in over 95% of cases yet the prevalence of fractures is in the range of 15-20%. The Ottawa ankle rules have been designed to reduce the need for radiographs in these patients and associated healthcare costs. This study aimed to validate the Ottawa ankle rules within our local setting and assess the impact of introduction of the rules.

Methods: This was a cross sectional study at the Aga Khan University Hospital A&E department and the orthopedic outpatient clinics. Consenting patients with ankle trauma were examined based on the criteria set out in the Ottawa rules and subsequently sent for radiographs to confirm the presence or absence of a fracture.

Results: The study recruited 175 patients over a six month period. There were 27 fractures with an incidence of 15%. The decision rule had a sensitivity of 96.3% and specificity of 57.4%. The negative predictive value was 98.8%. Application of these rules showed a potential of reducing the requested radiographs by 46%.

Conclusion: The results have shown that implementation of the rules will result in significant savings in cost, time and unnecessary radiation exposure.