Background: The Ottawa Ankle Rules provide guidelines for clinicians on the recommendation of radiographic tests to verify fractures in patients with ankle injuries. The use of the Ottawa Ankle Rules by emergency nurses has been suggested to minimise unnecessary radiographic-test requests and reduce patients' length of stay in emergency departments. However, the findings of studies in this area are inconsistent. Design: A systematic review was conducted to synthesise the most accurate evidence available on the extent to which emergency nurses' use of the Ottawa Ankle Rules to initiate radiographic tests improves healthcare outcomes for patients with ankle injuries. Data sources: The systematic review attempted to identify all relevant published and unpublished studies in English and Chinese from databases such as Ovid MEDLINE, EMBASE, ProQuest Health and Medical Complete, EBM Reviews, SPORTDiscus, CINAHL Plus, the British Nursing Index, Scopus, the Chinese Biomedical Literature Database, China Journal Net, WanFang Data, the National Central Library Periodical Literature System, HyRead, the Digital Dissertation Consortium, MedNar and Google Scholar. Review methods: Two reviewers independently assessed the eligibility of all of the studies identified during the search, based on their titles and abstracts. If a study met the criteria for inclusion, or inconclusive information was available in its title and abstract, the full text was retrieved for further analysis. The methodological quality of all of the eligible studies was assessed independently by the two reviewers. Results: The search of databases and other sources yielded 1603 records. The eligibility of 17 full-text articles was assessed, and nine studies met the inclusion criteria. All nine studies were subjected to narrative analysis, and five were meta-analysed. All of the studies investigated the use of the refined Ottawa Ankle Rules. The results indicated that emergency nurses' use of the refined Ottawa Ankle Rules minimised unnecessary radiographic-test requests and reduced patients' length of stay in emergency departments. However, the use of these rules in urgent-care departments did not reduce unnecessary radiographic-test requests or patients' length of stay. The implementation of the refined Ottawa Ankle Rules by emergency nurses with different backgrounds, including nurse practitioners or general emergency nurses was found to reduce patients' length of stay in emergency departments. Conclusions: The results of the systematic review suggested that a nurse-initiated radiographic test protocol should be introduced as standard practice in emergency departments. (C) 2016 Elsevier Ltd. All rights reserved.