Background and aims Ankle injuries (AI) are a common presentation to Paediatric Emergency Departments (PED). The Low Risk Ankle Rule (LRAR) is a validated clinical decision to determine grounds for radiography. It identifies swelling and tenderness isolated to the distal fibula and adjacent lateral ligaments distal to the anterior tibial joint line as low-risk; where ankle radiography (aXR) is not necessary to further exclude injury. The primary outcome is to evaluate LRAR in PED; with secondary aim to determine potential cost-savings.

Method LRAR was applied retrospectively to all paediatric aXR performed over 6-months (1/04/13–1/10/13) following presentation to PED with an AI. Data was accessed using Electronic Patient Records.

Results 311 aXR were performed of which 175 had sufficient data to be included in the study. Applying LRAR, 110 children fit the low-risk group (LRG.) Thus 110 unnecessary aXR were performed (62.86% reduction,) producing savings of £1,650. Within the LRG 8 fractures were confirmed but required no treatment beyond short-term below knee Plaster-Of-Paris, Aircast^® boot or equivalent. 3 received no treatment or follow-up. There were 26 fracture clinic referrals from the LRG. All 21 non-fractures were discharged at initial follow-up. The confirmed fractures were all discharged by second follow-up. Applying LRAR would have reduced follow-up resulting in cost-savings of £8,068; in total £9,718.

Conclusion Implementing the LRAR in children presenting with AI in the UK is safe from a clinical view point; will reduce radiography and follow-up, resulting in significant cost-savings.