Attending Physician Ann & Robert H. Lurie Children's Hospital of Chicago Chicago, Illinois, United States
Background: Pocket-sized ultrasound (PsUS) is a new tool in point-of-care ultrasonography, with the benefits of being portable, comparably more affordable, and relatively easy to use. However, limited research exists that evaluates the accuracy of PsUS in assessing pediatric elbow injuries. Objective: Our main objective was to determine the preliminary accuracy of PsUS in diagnosing the presence or absence of pediatric elbow fractures, when compared to radiographs or nursemaid reduction. Our secondary objective was to assess the quality of PsUS exams. Design/Methods: This prospective pilot study included the enrollment of children between 1-16 yo with acute ( < 48 hrs) isolated elbow pain. The PsUS elbow exam was performed on both elbows by physicians after a brief training curriculum. A positive PsUS was defined as the presence of an elevated posterior fat pad (PFP), with or without lipohemarthrosis, cortical disruptions or discontinuities in the bones’ contour (Figure 1). Patients then underwent standard clinical care for their elbow injury, which involved either an x-ray for suspected fracture or a nursemaid reduction for suspected radial head subluxation. A 1 month follow-up was performed to check for a clinical change from the initial evaluation. PsUS videos were also reviewed for image quality. Results: Thirteen subjects were enrolled, with a mean age 7 yo (SD 3.9 years, range 17 mo-14 yo) (Figure 2). Eight (62%) patients had a positive PsUS indicating an elbow fracture, with all 8 showing elevated PFP on PsUS imaging (Table 1). When the PsUS interpretation was compared to the initial diagnosis (fracture or no fracture, determined by the initial x-ray or reduction), PsUS showed encouraging accuracy of 92%, with sensitivity 100% (CI 95%, 59-100) and specificity 83% (CI 95%, 36-100). However, when subsequent follow-up imaging was included, the accuracy dropped to 77%, with sensitivity 100% (CI 95%, 48-100) and specificity 63% (CI 95%, 24-91). Twenty-six elbows were examined, with 258 PsUS video images obtained. Two videos were missed but images were otherwise rated as adequate in terms of quality. The main limitations of the study include small sample size as well as variability in image obtainment.
Conclusion(s): This study showed an encouraging accuracy for PsUS when compared to x-rays in the diagnosis of pediatric elbow injuries. This study also reenforced the feasibility of the study’s elbow exam protocol in injured children and the consistency of adequate quality images by novice PsUS users. This pilot has set the foundation for future investigations of PsUS in the diagnosis of pediatric elbow fractures. Figure 1.jpeg
