Objectives: In children with radiograph fracture-negative lateral ankle injuries, the main objective of this pilot study was to explore the accuracy, sensitivity, and specificity of point-of-care ultrasound (POCUS) performed by a pediatric emergency physician in diagnosing anterior talofibular ligament injuries, radiographically occult distal fibular fractures, and effusions compared with reference standard magnetic resonance imaging (MRI).
Methods: This was a prospective cohort pilot study. Children aged 5 to 17 years with an isolated, acute lateral ankle injury and fracture-negative ankle radiographs were eligible for enrolment. Within 1 week of the injury, enrolled children returned for MRI and POCUS of both ankles.
Results: Seven children were enrolled, with a mean age 12.1 (SD, 3.0) years. Overall, POCUS agreed with MRI with respect to anterior talofibular ligament injury in 4 (57%) of 7 cases. Of the 2 cases with MRI-confirmed ligament damage, POCUS accurately identified and graded the extent of ligament damage in 1 case. Point-of-care ultrasound falsely identified ligament injuries in 2 cases. Both imaging modalities confirmed the absence of cortical fractures in all 7 cases. For all findings, POCUS sensitivity and specificity were 57% and 86%, respectively.
Conclusions: In this pilot study, we established that POCUS diagnosed the specific pathology of radiograph-negative lateral ankle injuries with poor sensitivity but good specificity. Thus, POCUS could act as a tool to exclude significant ligamentous and radiographically occult bony injury in these cases. A larger study is needed to validate the utility of POCUS for this common injury.