SLR - June 2018 - Garret L. Strand

Retrospective Comparison of the Low-Risk Ankle Rules and the Ottawa Ankle Rules in a Pediatric Population

Reference: Ellenbogen A, Rice A, Vyas P. Retrospective comparison of the Low Risk Ankle Rules and the Ottawa Ankle Rules in a pediatric population. American Journal of Emergency Medicine. 2017 Sept 01; 35(9), 1262–1265.

Scientific Literature Review

Reviewed By: Garret L. Strand, DPM
Residency Program: Ascension–Wheaton Franciscan, Milwaukee, WI

Podiatric Relevance: Podiatric physicians are commonly consulted on many types of trauma pathology through the emergency department, including ankle injuries in the pediatric population. Quick and accurate diagnosis is crucial for these patients and utilizing specific guidelines helps to enhance this ability. Traditionally, the Ottawa Ankle Rule (OAR) remains a well-validated tool in correctly identifying the need for radiographs. Recently, the Low-Risk Ankle Rule (LRAR) has shown promising results in reducing the number of x-rays performed while maintaining high sensitivity. This study retrospectively reviewed 28 high-risk pediatric fractures and investigated the clinical decisions based on the LRAR and the Ottawa Ankle Rule (OAR).

Methods: This is a level IV retrospective review of 980 qualifying patients aged one to 18 years old. Patients' records were reviewed and determined if the patients met criteria for an ankle x-ray under each of the OAR and the LRAR criteria. Sensitivity and specificity were calculated as a percentage of patients with/without radiographically confirmed high-risk fracture that would have been correctly identified by applying the clinical decision rule in the ED, respectively. The potential reduction in obtained x-rays was expressed as a percent reduction and calculated by (total number of radiographs obtained – number of radiographs that would been ordered solely based on the clinical decision rule)/ total number of radiographs obtained.

Results: A total of 28 high-risk ankle fractures were identified. Applying OAR criteria, all 28 fractures would have been identified. OAR had a sensitivity of 100 percent, specificity of 33.1 percent and reduced number of x-rays ordered by 32.1 percent. LRAR would have missed four high-risk fractures, including a spiral fracture of the tibia and multiple SH II-IV tibia fractures. LRAR sensitivity was 85.7 percent, specificity was 64.9 percent and x-ray reduction potential was 63.1 percent. With patients one to two years of age, OAR and LRAR had 100 percent sensitivity and 77.8 percent specificity, but these results are imprecise estimates due to the same sample size.

Conclusions: These results show LRAR sensitivity among one to 18 year olds were lower than found in previous studies. The specificity of LRAR was greater than OAR, but four high-risk fractures would have been missed. Therefore, LRAR is not sensitive enough to be implemented in the pediatric ED population. A small sample size was a limitation of this study. Only 2 percent of clinicians' 980 notes mentioned the clinical decision rules. OAR remains an important clinical decision-making skill that should be used in the acute care setting. Proper utilization of this rule can help reduce healthcare costs, ED wait times and consequently improve patient satisfaction.  

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