Cost Consequence Analysis of Implementing the Low Risk Ankle Rule in Emergency Departments

Implementation of the Low Risk Ankle Rule can safely reduce radiographs for children with acute ankle injuries. The main objective of this study is to examine the costs and consequences of implementing the rule.

For children aged 3 to 16 years and with an acute ankle injury, we collected data on health care provider visits, imaging, and treatment at the index emergency department (ED) visit and days 7 and 28 post-ED discharge. This was done during 3 consecutive 6-month phases at 6 EDs. After the baseline phase 1, the Low Risk Ankle Rule was introduced in phases 2 and 3 in 3 intervention EDs, but not in the 3 pair-matched control EDs. We compared the effect of the Low Risk Ankle Rule on health care and patient-paid costs, the proportion of radiographs ordered, the proportion of missed clinically important fractures, and the follow-up use of health care resources.

We enrolled 2,151 children with ankle injuries, 1,055 at the intervention and 1,096 at the control EDs. Health care costs were $36.93 less per patient at intervention compared with control sites (P=.02). Out-of-pocket costs to the patients were $2.09 more per patient at intervention sites (P=.30). In intervention versus control sites, the main contributor to cost reduction was the 22.9% reduction in ankle radiography. Furthermore, there were no significant differences in the frequency of missed clinically important fractures (0.1% versus 0.9%) or follow-up use of health care resources.

Widespread implementation of the Low Risk Ankle Rule may lead to reduction of unnecessary radiographs for children and result in cost savings.