Evaluation of the Ottawa clinical decision rules for the use of radiography in acute ankle and midfoot injuries in the emergency department: an independent site assessment.

STUDY OBJECTIVE: Decision rules for the use of radiography in acute ankle and midfoot injuries have been developed. Radiographs are indicated if there is tenderness at the posterior edge or tip of either malleolus or at the navicular or base of the fifth metatarsal or there is inability to both weight bear immediately after the injury and ambulate four steps in the emergency department. This study assessed the efficacy of these rules with health care providers who had not been involved in their development.

DESIGN: Prospective patient survey by emergency department attending physicians and triage nurses.

SETTING: EDs of a university hospital and a community hospital with a combined annual volume of 100,000.

PARTICIPANTS: One hundred ten patients older than 16 years who presented with acute blunt ankle and midfoot trauma during the 3 months of summer 1993.

RESULTS: Fourteen fractures were diagnosed. When used by ED attending physicians, the decision rules had a sensitivity of 1.0 and specificity of 0.19 in detecting all midfoot and ankle fractures. When used by triage nurses, the sensitivity was 0.9 and specificity was 0.1. The negative predictive values of the decision rules were 1.0 for ED attending physicians and 0.88 for triage nurses. ED attending physicians and triage nurses agreed in 90% of cases regarding the overall decision to obtain radiographs. However, there was only a 47% agreement on all components of the clinical decision rules, with kappa values ranging from 0.60 to 0.76. The accuracies of the predictive rules were similar as applied by the ED attending physicians and the triage nurses (chi 2, P = .23). Application of the Ottawa predictive rules by ED attending physicians would have resulted in a 19% reduction in use of midfoot and ankle radiographs.

CONCLUSION: Use of the Ottawa and midfoot clinical decision rules by ED attending physicians of institutions not familiar with the rules' development resulted in 100% sensitivity for all fractures and would have allowed these physicians to safely reduce the number of radiographs ordered by 19%.