The main purpose of this project is to investigate the accuracy of pocket-sized ultrasound (PsUS) in the diagnosis of pediatric elbow fractures. The primary research objective is to determine the test performance characteristics of PSUS performed by pediatric emergency medicine physicians compared to radiography for the detection of pediatric elbow fractures. The project will consist of two parts, first involving a feasibility study and followed by an active study. The feasibility study will aim to answer if providers can perform an adequate elbow ultrasound exam after a brief study training. The active study will investigate the initial accuracy of the PsUS. Participants will be asked in either the feasibility or the active phases of the study to undergo a brief pocket-sized ultrasound elbow exam of both elbows. Patient will continue to receive their previously determined clinical ED management. In the active phase of the study, participant's elbow X-rays or if patient underwent bedside nursemaid reduction will be the comparison to pocket-sized ultrasound images.

The main purpose of this project is to investigate the accuracy of pocket-sized ultrasound (PsUS) in the diagnosis of pediatric elbow fractures. The primary research objective is to determine the test performance characteristics of PSUS performed by pediatric emergency medicine physicians compared to radiography for the detection of pediatric elbow fractures. The project will consist of two parts, first involving a feasibility study and followed by an active study.

This project will consist of two parts, involving first a brief feasibility phase followed by a pilot study conducted in an urban pediatric emergency department (Comer Children's Hospital in Chicago, IL). For the feasibility phase, the purpose is to demonstrate that novice PsUS users are able to obtain accurate and adequate imaging for interpretation. This phase will initially involve the study providers receiving the elbow PsUS exam training. Once trained, each study provider will obtain 3 elbow exams of participants between the ages of 1-16 years old. Providers will use the standardized views reviewed in the ultrasound training to perform the exam, with verbal consent obtained from each participant's parent for inclusion in the feasibility study. These images will be reviewed by study staff to ensure US examiners are obtaining the correct standardized views.

Once the feasibility exams are completed, the study providers are able to begin active study recruitment which will involve recruiting children between the ages of 1-16 years old with isolated acute elbow pain. Parents will initially be approached in the emergency department (ED), with written consent obtained if interested and eligible. Once consented, patients will undergo bilaterally standardized elbow exams using the pocket-sized ultrasound. All images will be stored on a password protected, cloud-based imaging database with all identifying information removed. After the exam, a basic assessment of the images will be made by the bedside ultrasound provider, as positive, negative or equivocal for signs of elbow fracture, but before reviewing any radiographic imaging. A positive PsUS will be defined as the presence of signs of elbow fracture, either as direct signs including cortical discontinuities or indirect signs including posterior fat pad with or without lipohemarthrosis on ultrasound exam. Following the ultrasound exam, patients will undergo standard clinical care for acute elbow injury per primary ED team which may consist of Xray or possible bedside nursemaid reduction. When applicable, study investigators will review the final blinded radiology readings of the initial or subsequent x-ray images after the patient encounter. Additionally, research staff will also attempt to follow up with participants after their ED visit for their elbow injury to determine if any additional radiographic imaging or care was obtained and if subsequent occult fractures were discovered on later imaging that may have been missed on the initial evaluation.

The primary aim of the feasibility portion of the study is to determine acceptability of the PsUS study training to obtain adequate elbow images. The primary aim of the active study is to compare the initial test performance characteristics of PSUS performed by bedside physicians compared to standard radiography in the diagnosis of pediatric elbow fractures.

Inclusion Criteria:

For Feasibility phase: children between the ages of 1-16 years olds

For Active phase: children between the ages of 1-16 years olds with isolated, acute (less than 48 hrs) elbow pain in the setting of adequate history of trauma

Exclusion Criteria:

Both phases:

• Children <1 or >16 years old
• Those with open fractures, gross deformities, multiple traumatic injuries, distal neurovascular compromise, unstable vital signs or hemodynamic instability, altered mental status, history of skeletal abnormalities, or past elbow fracture as well as wards of the state or those unable to provide consent
• Patients who have a confirmed diagnosis of fracture at an outside institutions prior to arrival to the ED will also be excluded

This study does not plan to share information with other researchers

1 ED visit (single day).

Given time restraints of the study, slow recruitment and pandemic-related fluctuations in pediatric ED visits, the active portion of the study was not successful in enrolling the sample goal of 70. As a result, the sample size was too small to perform additional statistical tests given poor power.