Point-of-Care Ultrasound Fracture–Physis Distance Association with Salter–Harris II Fractures of the Distal Radius in Children: The “POCUS 1-cm Rule”

Abstract

Salter–Harris II fractures of the distal radius can result in serious complications. The aim of this study was to measure the fracture–physis distance using point-of-care ultrasound (POCUS) to determine whether a certain distance is associated with Salter–Harris II fractures, compared with other fracture types, in a cohort of children with X-ray–identified distal radius fractures. Participants were from a parent diagnostic study conducted in an Australian tertiary pediatric emergency department, which prospectively evaluated the diagnosis of pediatric distal forearm fractures using POCUS compared against X-ray. Nurse practitioners, who underwent 2 h of training, administered a six-view POCUS protocol in clinically non-angulated pediatric forearm injuries prior to X-ray. This was a secondary analysis of data from the parent study. The 122 participants with X-ray–identified distal radius fractures from the parent study had their POCUS images interpreted by two emergency physician sonologists, who measured the fracture–physis distance. The median and maximum fracture–physis distances for Salter–Harris II fractures (n = 19) were 8.00 and 9.85 mm, whereas minimum and median distances for incomplete fractures (n = 22) were 10.20 and 15.98 mm, and those for complete fractures (n = 9) were 10.85 and 12.85 mm. Buckle fracture (n = 72) distances ranged from 4.35 to 26.55 mm, with a median of 13.65 mm. In children diagnosed with a distal radius fracture on X-ray, a fracture–physis distance cutoff of 1 cm differentiated Salter–Harris II fractures from other cortical breach fracture types, but not buckle fractures. Although this exploratory study suggests the “POCUS 1-cm rule” could be used as a secondary sign to augment the diagnosis of Salter–Harris II distal radius fractures using POCUS, further research is required to validate this measurement prospectively.