Purpose: The Ottawa ankle rule (OAR) is a clinical decision rule used in emergency departments to identify which patients with acute ankle/midfoot injury require radiography. The purpose of this study was to implement the OAR, with a modification to improve the specificity for identifying malleolar fractures (the "Buffalo rule"), in a sports medicine center and measure impact on physician practice and cost savings.
Methods: All pediatric and adult patients presenting to a university sports medicine walk-in clinic with acute (< or = 10 d old) ankle/midfoot injury had the rule applied by primary care providers. Exclusion criteria included pregnancy, isolated skin injury, > 10 d since injury, second evaluation for same injury, obvious deformity of ankle or foot, or altered sensorium.
Results: In 217 patients (mean age, 23.3 +/- 8.5 yr; range, 10-64 yr) there were 24 clinically significant (i.e., nonavulsion) fractures (fracture rate 3.7% per year for 3 yr), all of which were identified by the rule (100% sensitivity). In 193 patients with malleolar pain, the sensitivity for malleolar fracture (with 95% confidence intervals) was 100% (78-100%) and specificity was 45% (43-46%). In 24 patients with midfoot pain, sensitivity was 100% (65-100%) and specificity was 35% (21-49%). Thirty-five percent of radiographic series (76 of 217) were foregone for a cost savings of almost $6000. One hundred percent follow-up on those patients for whom x-rays were obtained found no missed fractures and they were subjectively satisfied with their care.
Conclusion: The OAR reduced radiography in acute ankle/midfoot injury and saved money in relatively younger patients in the outpatient sports urgent care setting without missing any clinically significant fractures. The specificity of the Buffalo malleolar rule in the present implementation study, however, was not a significant improvement over the OAR malleolar rule. Widespread application of the OAR could save substantial resources without compromising quality of care.