Validation of the Ottawa Knee Rules

Study objective: We sought to validate the Ottawa Knee Rules for determinin g the need for radiography in patients with acute knee injury. Methods: A prospective cohort study was, performed in emergency departments of 11 hospitals of the Osakidetza-Basque Country Health Service. The patie nt population was composed of a convenience sample of 1,522 eligible adults of 2,315 patients with acute knee injuries. The attending emergency physic ians assessed each patient for Standardized clinical variables and determin ed the need for radiography according to the decision rule. Radiography was performed in each, patient, irrespective of the determination of the rule, after clinical evaluation findings were recorded. The rule was assessed, f or the ability to correctly identify fracture of the knee. Results: The decision rule had a sensitivity of 1.0 (95% confidence interva l [CI] 0.96 to 1.0), identifying 89 patients with clinically important frac tures. The potential reduction in use of radiography was estimated to be 49 %, The probability of fracture the decision rules were negative, is estimat ed W be 0% , (95% Cl 0% to 0.5%). Conclusion: Prospective validation has shown the Ottawa Knee Rules to, be 1 00% sensitive for identifying fractures of the knee and to have the potenti al to allow physicians to reduce the use of radiography in patients with ac ute knee injuries.