Nurse practitioner administered point-of-care ultrasound compared with X-ray for children with clinically non-angulated distal forearm fractures in the ED: a diagnostic study

BACKGROUND: Paediatric distal forearm fractures are a common ED presentation. They can be diagnosed with point-of-care ultrasound (POCUS) as an alternative to X-rays. Given that ED nurse practitioners (NPs) are relied on for the diagnosis of paediatric fractures, it is important to describe the diagnostic accuracy of NP-conducted POCUS versus X-ray. METHODS: This prospective diagnostic study was conducted in a tertiary paediatric hospital in Queensland, Australia, between February 2018 and April 2019. Participants were children aged 4-16 years with a clinically non-angulated, suspected distal forearm fracture. Diagnosis from 6-view NP-administered POCUS of the distal radius and ulna was compared against the reference standard of 2-view X-ray. Each patient received both imaging modalities. Overall forearm diagnosis was classified as 'no', 'buckle' or 'other' fracture for both modalities. The primary outcome was diagnostic accuracy for 'any' fracture ('buckle' and 'other' fractures combined). Secondary outcomes included diagnostic accuracy for 'other' fractures versus 'buckle' and 'no' fractures combined, and pain, imaging duration and preference for modality. RESULTS: Of 204 recruited patients, 129 had X-ray-diagnosed forearm fractures. The sensitivity and specificity for NP-administered POCUS were 94.6% (95% CI 89.2% to 97.3%) and 85.3% (95% CI 75.6% to 91.6%), respectively. 'Other' fractures (mostly cortical breach fractures), when compared with 'buckle'/ 'no' fractures, had sensitivity 81.0% (95% CI 69.1% to 89.1%) and specificity 95.9% (95% CI 91.3% to 98.1%). Pain and imaging duration were clinically similar between modalities. There was a preference for POCUS by patients, parents and NPs. CONCLUSIONS: NP-administered POCUS had clinically acceptable diagnostic accuracy for paediatric patients presenting with non-angulated distal forearm injuries. This included good sensitivity for diagnosis of 'any' fracture and good specificity for diagnosis of cortical breach fractures alone. Given the preference for POCUS, and the lack of difference in pain and duration between modalities, future research should consider functional outcomes comparing POCUS with X-ray in this population in a randomised controlled trial.