Validation of the ottawa ankle rules at a tertiary teaching hospital: a cross-sectional study

Introduction: Ankle joint and foot injuries are among the commonest injuries seen at the Accident and Emergency Department of any hospital. Within the United States it is the second most common musculoskeletal injury seen by physicians. Assessment of these injuries is done clinically and when deemed necessary a radiograph is requested. Studies have shown that radiographs are ordered in over 95% of cases yet the prevalence of fractures is in the range of 15-20%. This means that more than 80% of patients are exposed to unnecessary radiation. The Ottawa ankle rules have been designed to reduce the need for performing X-ray examinations in these patients and thus reduce healthcare costs significantly. The rules have not been utilised or validated in an african set-up within a private institution similar to our setting and yet could significantly reduce costs and time in management of these patients. This study thus aimed to validate the Ottawa ankle rules within our local setting and assess the impact of introduction of the rules. Materials and methods: The study was a cross sectional study done within the setting of Aga Khan University Hospital Accident and Emergency Department and the orthopaedic outpatient clinics. The Physicians were trained on how to use the rules. After obtaining consent, patients were enrolled in the study, before examination based on the criteria set out in the Ottawa rules was carried out. Subsequently they were sent for radiographs to confirm the presence or absence of a fracture. Data collected was entered into a data sheet and analysed for sensitivity, specificity, positive and negative predictive values when using the Ottawa ankle rules. Results: The study recruited 175 patients over a six month period. There were 27 fractures with an incidence of 15.0%. The decision rule had a sensitivity of 96.3% (79.1 to 99.8%) and specificity of 57.4% (49.0 to 65.4%). The negative predictive value was 98.8% (92.7 to 99.9%). Application of these rules showed a potential of reducing the requested radiographs by 43.0%. Conclusion: The study results have shown that implementation of the rules will results in significant savings in cost, time and unnecessary radiation exposure