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.