What diagnostic imaging is usually unnecessary for a child suspected of having a radial head subluxation?

In cases of suspected radial head subluxation in children, standard x-rays are generally unnecessary for diagnosis. This condition, commonly known as "nursemaid's elbow," typically occurs due to a sudden pull on the child's arm, causing the radial head to slip out of its normal position. The clinical diagnosis is often made based solely on the child's history, the mechanism of injury, and the physical examination findings—such as pain and reluctance to use the affected arm.

Standard x-rays could be used to rule out other injuries in circumstances where there might be suspicion of a fracture, but they are not required to confirm radial head subluxation itself, as the condition does not usually result in any bony abnormalities that would be visible on x-rays.

In contrast, MRI and CT scans are more specialized imaging techniques that provide detailed information on soft tissues and could be considered for more complex cases or when there is suspicion of associated injuries. Ultrasound may sometimes be used for soft tissue evaluation but is not routinely required for diagnosing simple cases of radial head subluxation. Therefore, it is the standard x-ray that is most often unnecessary in these situations.