Can Emergency Department Triage Nurses Appropriately Utilize the Ottawa Knee Rules to Order Radiographs?—An Implementation Trial

Objective: To determine whether triage nurses can successfully interpret the Ottawa Knee Rule (OKR) and order knee radiographs according to the OKR. Methods: This was a prospective implementation trial of a clinical decision rule, set in a suburban, community emergency department (ED), evaluating a convenience sample of ED patients aged > 17 years with acute knee injuries. Patients were excluded for altered mental status, distracting injuries, and knee lacerations. Triage nurses and attending emergency physicians (EPs) were trained in appropriate use of the OKR. The triage nurses evaluated eligible patients and radiographs were ordered according to their interpretation of the OKR. EPs who were initially blinded to the triage assessments also evaluated the patients. EPs could add an x-ray order if, according to their assessment of the OKR, one was indicated and a radiograph had not been ordered by the nurse. Nurses and EPs recorded their blinded assessments on standardized data collection instruments. Kappa values were calculated to assess interobserver agreement (IOA) between nurses and EPs; sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) were calculated as appropriate. Results: One hundred three patients were enrolled; 53% were female; 10 fractures were identified (9.7%). The IOAs between the nurses and EPs for each of the criteria were moderate to almost perfect: age-0.94; fibular head tenderness-0.4; isolated patellar tenderness-0.68; inability to bend knee to 90 degrees-0.73; inability to bear weight-0.76. The IOA was moderate (0.52) for the overall interpretation of the OKR by nurses and EPs. Sensitivity of nurse interpretation of the OKR for fracture was 70%, specificity 33%, NPV 91%, PPV 10%. Sensitivity of EP interpretation of the OKR for fracture was 100%, specificity 25%, NPV 100%, PPV 13%. Conclusions: Triage nurses showed fair to good ability to appropriately apply the OKR to pre-order knee radiographs.