From the Guidelines
For a 14-year-old male with a suspected Salter-Harris type 1 fracture of the distal fibular physis, MRI is the best diagnostic imaging modality to evaluate potential fracture and displacement, particularly when concerns for injury to the Anterior Talofibular Ligament (ATFL) and Calcaneofibular Ligament (CFL) are present. When evaluating a potential fracture and displacement in a pediatric patient, it is crucial to consider the limitations of plain radiographs in detecting Salter-Harris type 1 fractures, which occur through the growth plate without extending into the metaphysis or epiphysis 1.
Key Considerations
- MRI is the reference standard for ligamentous injury and assessment of stability, particularly important in athletes, and allows for high-resolution evaluation of tendons and ligaments to distinguish between tendinopathy, sprain, and partial or complete tears 1.
- Ligament and tendon injuries can occur without fracture on radiography, and MRI can detect bone marrow edema across the physis, confirming the diagnosis when radiographs appear normal 1.
- The presence of bone bruise and adjacent soft-tissue edema have shown a higher association with acute ligamentous injuries, including those to the ATFL, and tendon abnormalities, even in patients with negative radiographs 1.
Diagnostic Approach
- While plain radiographs with anteroposterior, lateral, and mortise views of the ankle are typically the initial imaging study, they may not be sufficient for detecting Salter-Harris type 1 fractures or ligamentous injuries 1.
- MRI should be performed if clinical findings suggest a physeal injury, as it provides superior visualization of cartilage and soft tissue injuries, including ligament damage to the ATFL and CFL 1.
Conclusion Not Applicable - Answer Continues
This approach prioritizes the need for accurate diagnosis while considering the potential limitations and benefits of different imaging modalities in the context of pediatric patients with suspected Salter-Harris type 1 fractures and ligamentous injuries.
Additional Considerations
- The American College of Radiology (ACR) Appropriateness Criteria recommend MRI for evaluating ligamentous injuries and assessing stability in acute ankle trauma, particularly in athletes 1.
- Ultrasound (US) may be useful in certain scenarios but is not typically considered the first line of imaging for evaluating acute trauma to the ankle with positive Ottawa Ankle Rules (OAR) 1.
From the Research
Diagnostic Imaging Modalities
To evaluate a potential fracture and displacement in a 14-year-old male with a suspected Salter-Harris type 1 fracture of the distal fibular physis, the best diagnostic imaging modality can be considered based on the following points:
- MRI is a sensitive tool for diagnosing Salter-Harris type I fractures, especially when radiographs are normal or inconclusive 2.
- A study found that none of the included patients had evidence of Salter-Harris type I fracture of the distal fibula on MRI, highlighting the high false-positive rate of clinically suspected Salter-Harris type I fractures 2.
- CT examination with multiplanar reconstruction can be used in pre-operative assessment of distal femur growth plate fracture, but its use in distal fibular physis fractures is not well-established 3.
Considerations for Injury to the Anterior Talofibular Ligament (ATFL) and Calcaneofibular Ligament (CFL)
When evaluating the potential injury to the ATFL and CFL, consider the following:
- Ligamentous lesions, bone contusion, or joint effusion are common findings in children with ankle injuries, rather than Salter-Harris type I fractures 2.
- The diagnosis and treatment of distal fibular Salter-Harris I fractures may vary between emergency physicians and orthopedic physicians, highlighting the importance of referral for orthopedic evaluation 4.
- Open reduction and internal fixation may be necessary for displaced Salter-Harris type I distal fibula fractures, especially when there is concern for premature physeal closure, fibular growth disturbance, syndesmotic instability, or medial (deltoid ligament) injury 5, 6.