The bone fracture is usually diagnosed using an X-ray examination (the method of choice). However, in the case of the youngest patients (children and adolescents), it carries a potential risk of X-ray radiation exposure. What is important, an X-ray examination often fails to detect occult fractures or the early stages of a fracture with or without bone fusion. The literature emphasizes that from 2 to 36% of fractures may be unnoticed on X-ray images (false negative results). Therefore, additional possibilities are sought to improve the initial diagnosis.

It was shown that ultrasound could be used instead of the conventional imaging. The most important advantages of the usg are the absence of radiation exposure and greater availability. Moreover, the evaluator is able to show neovascularization during usg examination, which is important in bone healing process.

The aim of this study is (1) to validate the ultrasound imaging method for the fracture management; (2) to use an ultrasound imaging to assess the bone fracture and healing process during 8 weeks post injury.

This study consists of 50 patients aged 10-18 years old. The forearm fracture will be diagnosed using an X-ray imaging as well as an ultrasound imaging in the first 3 days post injury (initial study). It is planned to assess the healing process after 2, 4, 6 and/or 8 weeks post injury (comparative study).

The physiological fracture healing is based on the proper facilitation of regeneration and proliferation process. The bone fracture is usually diagnosed using an X-ray examination. However, an ultrasound imaging could be used instead of the conventional imaging. It is important in the case of the youngest patients. In these cases, the Hubner protocol/algorithm is often used. The patients with suspected fracture are advised to perform an ultrasound examination. Only after the confirmation of a suspected fracture, an X-ray examination should be performed.

Bone structure show typical characteristics, which make an ultrasonography an attractive medical diagnostic tool. Highly dense tissues such as bone reflect echoes and, therefore, appear bright white on an ultrasound (reflection from the cortical surface of the bone). This allows bone to be clearly distinguished from the surrounding soft tissues.

It was shown that ultrasound is a good diagnostic tool to assess the fracture healing process. The advantage of usg is that it is non-invasive, does not use ionizing radiation and is performed in a real-time.

The first study about the ultrasound in the diagnosis of fracture was carried out in 1988 in a group of 41 newborns with suspected clavicle fractures after complicated delivery. In all cases, the collarbone fracture was easily identifiable by an ultrasound in the first few days after the injury. Moreover, these data correlated with the conventional X-ray imaging.

It was also shown that the ultrasound method in pediatric patients can be used to visualize fractures, e.g. of the ribs or the sternum. In the acute phase, disturbances in the cortical layer of the bone as well as recent hematoma are easily observed. In the later phase, the formation of a callus (callus hypertrophy) could be diagnosed.

The aim of this study is (1) to validate the ultrasound imaging method using variables such as repeatability, interclass correlation coefficient (Qw), relative standard deviation (rSD) etc.; (2) to use an ultrasound imaging to assess the bone fracture and healing process during 8 weeks post injury.

This study consists of 50 patients aged 10-18 years old. The forearm fracture will be diagnosed using an X-ray imaging as well as an ultrasound imaging in the first 3 days post injury (initial study). It is planned to assess the proper healing process after 2, 4, 6 and/or 8 weeks post injury (comparative study).

Ultrasound examination:

• the measurement of the humerus in two different projections (a-p and lateral). The distance from the acromion localized on the shoulder blade will be measured in order to repeat the examination in the same area.
• radial bone examination in two different projections (a-p and lateral). The distance from the radiocarpal joint space will be measured in order to repeat the examination in the same area.
• additionally, POWER Doppler assessment of callus neovascularization will be performed (each recording of the Doppler frame parameters for a given patient in order to repeat the examination at subsequent controls)

Experimental Design:

The fracture diagnosis is planned to be performed on the day of the injury, or at an interval of no more than 2-3 days post the injury as an initial examination and approx. during 8 weeks after the injury as a comparative examination (during the first control in an orthopedic clinic after 14 days, 4 weeks, 6 weeks and/or 8 weeks).

All the procedures performed in this study involving human participants will conform to the ethical guidelines of the 1975 Declaration of Helsinki (and its later amendments or comparable ethical standards, revised in 2013) and follow the Adapted Physical Activity (APA) Ethics Standard.

The protocol was approved by the Ethics Committee of Stanislaw Popowski Regional Specialized Children's Hospital in Olsztyn, Poland (number of approval: 6 ZE//2020/WSSD; date of approval: 22 May 2020).

The experiment will be conducted with the understanding of each subject. All subjects as well as their parents will give written informed consent before children's participation in this study.

Inclusion Criteria:

• the proximal end of the humerus and the distal end of the radius bones fractures
• voluntary participation and consent to participate in the study signed by the parent and patient
• declaration of participation in an X-ray and ultrasound examination during all 8 weeks post-injury
• no medical contraindications to participate in the study program

Exclusion Criteria:

• previous injuries of a similar body area
• plaster immobilization
• fractures referred for surgery

50 patients admitted to the Orhopaedics and Trauma Ward of Prof. dr Stanislaw Popowski Regional Specialized Children's Hospital in Olsztyn, Poland with trauma to the upper extremity (from the proximal of the wrist to distal of the glenohumeral joint with evidence of pain, tenderness or swelling of the limb). Patients will be devided into two groups of radius or humerus bone (RadiusFracture and HumerusFracture groups). All patients will be recruited starting from July 2020. In all patients, first ultrasound and then standard plain radiography will be performed.