Triage nurse application of the Ottawa knee rule

Objective: To determine interobserver agreement; between triage registered nurses (RNs) and emergency physicians (EPs) regarding indication for knee r adiographs by applying the Ottawa knee rule (OKR) and individual components of the rule. Methods: This was a prospective, observational study in a sub urban, teaching emergency department. The study enrolled a convenience samp le of patients aged >17 years with traumatic knee injuries less than one we ek old. Patients with prior knee surgery or distracting conditions were exc luded. Before study initiation, the RNs and EPs were in-serviced in the OKR . Nurses and EPs independently examined each patient for OKR criteria, blin ded to the other's assessment. Knee radiographs were ordered at the discret ion of the EP and were interpreted by board-certified radiologists. All pat ients received follow-up with a structured telephone interview to identify any undetected fractures. Kappa was calculated for each component and the o verall application of the OKR to assess interobserver agreement. Results: N inety-six patients were enrolled. The mean age was 39.6 +/- 18.7 years; 50% were male. Eight patients (8%) had knee fractures. Interobserver agreement s between the RNs and EPs for individual components of the OKR were: age gr eater than or equal to 55 years (kappa = 0.97); inability to weight bear (k appa = 0.51); inability to bend knee to 90 degrees (kappa = 0.52); fibular head tenderness (kappa = 0.45); and isolated patellar tenderness (kappa = 0 .40). The EPs and RNs agreed with OKR criteria for x-ray 71% of the time (k appa = 0.41). Conclusions: The only criterion that resulted in almost perfe ct agreement between the RNs and EPs was patient age; agreement for the oth er four criteria and the overall decision to order x-rays was moderate.