The Diagnostic Accuracy of Ultrasound in Detecting Distal Radius Fractures in a Pediatric Population

Abstract

Objective: Sports ultrasound (US) is becoming popular in diagnosing musculoskeletal injuries. This study, also called the Pediatric Distal Radius Ultrasound Study (PeDRUS), compared the diagnostic accuracy of sports US with plain radiographs in possible distal radius buckle fractures in pediatric population. Methods: In this prospective observational study, patients (2-15 years) presenting to an outpatient orthopedic injury clinic with distal forearm injuries without deformity were recruited. Bedside ultrasonography was performed and interpreted by the investigators as positive or negative for fracture. Plain radiographs were then performed and interpreted by the same investigator. The radiographs were considered the definitive imaging study for this investigation. Results: Fifty-one patients were included with a mean age of 9.9 years. Fractures were diagnosed on both US and plain radiographs in 34 patients. Fractures were ruled out on both US and plain radiographs in 16 patients. There was only one case in which the US was interpreted differently than radiograph. For fractures of the distal radius in this population, the sensitivity was 97.1% [95% confidence interval (CI) = 89.2-97.1] and the specificity was 100% (95% CI = 82.5-100). The positive predictive value was 100% (95% CI = 91.8-100), whereas the negative predictive value was 94.1% (95% CI = 77.7-94.1). The positive likelihood ratio was infinite, suggesting utility in confirming a fracture. The negative likelihood ratio was 0.03 (95% CI = 0.03-0.13), suggesting that US has value in ruling out a fracture. Conclusions: Our study suggests that diagnostic sports US is sensitive and specific for detecting distal radius fractures in pediatric patients with nondeformed forearm injuries, demonstrating that US is an acceptable alternative to plain radiographs for evaluating fractures in a pediatric population.