Point-of-care ultrasound, aka “POCUS,” may not be great for finding what x-rays miss in children’s injured ankles, but it proved specific enough in a recent pilot study to recommend itself for ruling out significant ligament tears and radiographically occult bone damage.

The study was published online May 15 in Pediatric Emergency Care.

Sarah Jones, MD, of the University of Toronto, and colleagues enrolled seven children aged 5 to 17 (mean age, 12.1 years) who had an isolated, acute lateral ankle injury and fracture-negative ankle radiographs upon initial examination in the emergency department.

The participants were then imaged with POCUS of both ankles performed by a pediatric emergency physician and, for reference, standard ankle MRI.

Overall, POCUS agreed with MRI with respect to anterior talofibular ligament injury in four of the seven cases (57 percent), the authors report.

POCUS also accurately identified and graded the extent of ligament damage in one of two cases with MRI-confirmed ligament damage.

However, POCUS falsely identified ligament injuries in two cases.

Both imaging modalities confirmed the absence of cortical fractures in all seven cases.

For all findings, POCUS sensitivity and specificity were 57 percent and 86 percent, respectively.

“[W]e established that POCUS diagnosed the specific pathology of radiograph-negative lateral ankle injuries with poor sensitivity but good specificity,” the authors write. “Thus, POCUS could act as a tool to exclude significant ligamentous and radiographically occult bony injury in these cases.”

A larger study will be needed to validate the utility of this application, they add.