EASY Algorithm Trial (Elbow Trauma Assessment Using Sonography in Children and Youth) Diagnostic Accuracy and Safety of Point-of-care Ultrasound as a Screening Tool for Suspected Elbow Fractures in Children Aged 5 to 15 Years: a Multicenter Prospective Cohort Study

Sensitivity of sonographic joint effusion examination following a standardized procedure and uniform training of the physicians performing the examination in the detection of radiologically confirmed elbow fractures, as assessed by blinded experts.

The total time for performing and evaluating the ultrasound examination is measured.

The time that patients and their relatives spend additionally in the emergency room due to X-ray imaging is measured. The time at which the family leaves the treatment room after the ultrasound is noted. Then the time at which the family re-enters the treatment room after the X-ray is performed is noted. The difference is the additional time patients spend in the emergency room due to X-ray imaging.

The radiation dose of the initial radiological imaging (dose area product) is recorded.

The exact fracture type determined by the attending physician in the emergency department.

In the case of a fracture diagnosed by X-ray, the initial treatment is recorded.

If the initial X-ray image shows no fracture, the initial symptomatic treatment is recorded. If there is initially no radiographic evidence of a fracture, a telephone follow-up and file review will be conducted after 6 weeks. Any changes in treatment during the 6 weeks following the initial presentation will be recorded.

The exact fracture pattern of the X-ray images as determined by blinded experts.

Radiographic posterior fat pad signs on the initial X-ray images taken during the initial presentation at the emergency room, which are assessed by blinded experts.

The sonographic images from the elbow joint sonography are subsequently re-evaluated by blinded physicians in order to examine interrater variability.

If no fracture is initially visible on the initial X-ray, a follow-up telephone call is made after 6 weeks. The child's pain is assessed using the PROMIS® Numeric Rating Scale v1.0 - Parent Proxy Pain Intensity 1a. This is a single-item scale for assessing average pain intensity from the parent's perspective (parent proxy), which has been validated for the 5 to 17 age group. The child's average pain intensity is recorded on a numerical scale from 0 ("no pain") to 10 ("the most severe pain imaginable"), taking into account the period of the last seven days.

If no fracture is initially visible on the initial X-ray, a follow-up telephone call is made after 6 weeks: The function of the child's upper extremity is assessed using the PROMIS® Parent Proxy Short Form v2.0 - Upper Extremity questionnaire. This is an official, validated short form derived from the PROMIS® item bank for upper extremity function from the parent's perspective (parent proxy). It assesses the limitations of children (aged 5-17 years) in relation to everyday activities that involve the upper extremities. The eight items are rated on a five-point Likert scale ranging from "No difficulty" to "Could not do." The final result is represented by the T-score-a standardized value with a mean of 50 and a standard deviation of 10.

After six weeks, the patient file is reviewed for possible re-examination at the study center. In the event of a re-examination, the date, symptoms, and, if applicable, any X-ray imaging, fracture type, and treatment are documented.

In addition, the parents are contacted by telephone after six weeks and asked about a possible appointment at an external clinic or doctor's office. If such a referral has taken place, the findings and any changes in treatment are recorded. If a bone fracture has been diagnosed for the first time in an external facility due to the same trauma, the X-ray images and findings are requested to be sent to the local study center so that they can be integrated into the patient file.

Potential confounders of the patients include age, sex assigned at birth, gender identity, pre-existing conditions, location of the accident (in daycare/school or outside of these settings), accident mechanism, swelling of the affected elbow, hematoma of the affected elbow, other fractures caused by the same trauma, and the time interval since the trauma.

Potential confounders of the attending physician in the emergency room, who is performing the sonography include previous experience with ultrasound imaging of fractures, the physician's area of expertise, and level of training.