Accuracy of Sonography in Elbow Trauma

Objective:

The primary objective is to compare the diagnostic accuracy of POCUS and XR with respect to diagnosing fractures of the elbow after an indirect elbow trauma in the ED setting and to investigate the rate of agreement between the two modalities.

The primary outcome is the difference in diagnostic accuracy between the two modalities with respect to diagnosing a radial head fracture and the degree of agreement between the two modalities.

Secondary outcomes are the difference in diagnostic accuracy between the two modalities and the rate of agreement with respect to the other fracture types, to the decisions "any fracture", and to the decision "any fracture other than radial head".

Experimental Intervention (medical device) POCUS: The ultrasound examination of the injured elbow includes seven standard settings. The probe is placed on the joint in four ventral and in three posterior positions. If hemarthrosis is detected, this is always suspicious of a possible intra-articular fracture. Even the smallest amounts of blood can be detected sonographically.

The surfaces of the bones involved in the joint (humerus, ulna, radius) are accurately displayed in all seven sonography settings. Disrupted bone surface indicates a fracture.

POCUS will be performed according to the local SOP.

Control Intervention (standard/routine/comparator) XR: The conventional radiograph of the injured elbow consists of three standard views: ap, lateral and Norman oblique. This X-ray examination is the most commonly performed technique to date to diagnose an injured elbow.

CBCT (Cone Beam Computed Tomography): The injured elbow is placed in an almost most extended position in the CBCT tube. For this purpose, the affected arm is placed and fixed on a carbon-splint. The examination time is about 40 seconds XR will be performed according to the standard procedures of the ED of the MIK. The same holds for CBCT.

Any of the three diagnostic procedures applied can be discontinued in the case of patient discomfort, harm, or risk of harm according to the standard procedures of the MIK.

Compliance of the staff of the ED with performing the three modalities is supported by SOPs and internal training.

In the case of withdrawal of a patient, the reasons are recorded on the CRF. The data of these patients will not be included in the statistical analysis. The data will not be deleted in the data management system. Patients who withdraw themselves are offered a chat with the PI and further consultations.

Patients included in the trial will follow the standard management at the MIK. There are only two changes:

• a CBCT is performed in addition after having performed both POCUS and XR, if there are no positive findings on POCUS or XR.
• an additional blinded evaluation of all CBCTs will be done by one independent rater.

CBCT will be ordered by the staff of the ED in all patients and may be preliminary evaluated. However, these evaluations will not be documented as part of this study. They are also not accessible for the staff at the Radiology Department in the routine evaluation of the XRs.

Inclusion criteria

• Informed Consent signed by the subject
• Suspicion for an indirect elbow trauma as part of the routine management at the ED of the MIK.

Exclusion criteria

• Age below 18
• Patients who are lacking capacity of judgment
• Patients with (temporary) cognitive impairment which makes an understanding of the patient information unlikely
• Patients with limited knowledge of German or English which makes an understanding of the patient information unlikely
• Patients with contraindications for US, XR or CT.
• Lack of informed consent