What is the most appropriate next step for a 3-year-old boy who refuses to bear weight after a trampoline incident, with no known fall or injury, and has a normal pulse in the affected extremity, but is fussy with movement of his leg at the knee?

From the Guidelines

The most appropriate next step for this 3-year-old boy is to obtain plain radiographs of the lower extremities, specifically limited tibial/fibula radiographs, to evaluate for a toddler's fracture or other bone injury. The child's refusal to bear weight after a trampoline incident, despite no known fall or injury, and fussiness with movement of his leg at the knee, suggests a possible fracture. According to the American College of Radiology Appropriateness Criteria 1, in children under 4 years of age, initial evaluation with limited tibial/fibula radiographs is suggested rather than total extremity radiographs. This approach is recommended because spiral tibial fractures are the most common fractures found in children under 4 years of age presenting with nonlocalized limp or refusal to bear weight.

Some key points to consider in this case include:

• The child's age and presentation are consistent with a toddler's fracture, which may not be immediately visible on initial x-rays 1.
• The presence of a normal pulse in the affected extremity is reassuring, but does not rule out a fracture.
• The fussiness with knee movement indicates pain and possible underlying injury.
• If initial imaging is normal but symptoms persist, follow-up radiographs or radiographs of areas besides the tibia/fibula may be useful, as approximately 10% of tibial fractures were only visible on follow-up radiographs and not initial imaging 1.

While waiting for medical attention, the leg should be immobilized and the child can receive weight-appropriate doses of ibuprofen or acetaminophen for pain relief. However, obtaining plain radiographs of the lower extremities is the most critical next step to evaluate for a possible fracture and guide further management.

From the Research

Assessment and Diagnosis

The 3-year-old boy's presentation to the ED with refusal to bear weight after a trampoline incident, despite no known fall or injury, warrants a thorough assessment to determine the cause of his symptoms. The boy's ability to playfully move his toes and the presence of a normal pulse in the affected extremity are positive signs. However, his fussiness with movement of his leg at the knee suggests potential injury or trauma to the knee or lower extremity.

Diagnostic Considerations

Given the clinical presentation, the following diagnostic considerations are relevant:

• The study by 2 highlights the importance of imaging in diagnosing lower extremity stress fracture injuries, which could be a potential cause of the boy's symptoms.
• The study by 3 compares the diagnostic accuracy of point-of-care ultrasonography and X-ray in diagnosing bony injuries of the knee, suggesting that X-ray is the most appropriate initial imaging modality.
• The study by 4 emphasizes the importance of X-ray before manipulation of ankle injuries, which may be relevant to the boy's knee injury.

Next Steps

Based on the available evidence, the most appropriate next step would be to perform an X-ray of the affected leg to rule out any bony injuries or fractures. This is supported by the study by 3, which suggests that X-ray is a reliable imaging modality for diagnosing knee fractures. Additionally, the study by 2 highlights the importance of imaging in diagnosing lower extremity injuries, and X-ray is a commonly used initial imaging modality.

Key Points

• X-ray is a reliable imaging modality for diagnosing knee fractures and other bony injuries.
• Imaging should be performed before any manipulation of the affected limb to avoid potential complications.
• The boy's symptoms and clinical presentation suggest a potential knee or lower extremity injury, which warrants further evaluation with X-ray.