From the Guidelines
MRI is the preferred imaging modality for suspected Salter-Harris type 1 fractures of the distal fibular physis, as spaced X-rays are unlikely to provide additional information. In this 14-year-old male with a suspected Salter-Harris type 1 fracture of the distal fibular physis, where the growth plate is not visible on initial x-ray, and there is concern for injury to the Anterior Talofibular Ligament (ATFL) and Calcaneofibular Ligament (CFL), an MRI will provide a comprehensive evaluation of both bone and soft tissue structures.
Key Points to Consider
- MRI can directly visualize physeal injury, ligamentous damage, and any associated cartilage or soft tissue injuries that X-rays cannot detect 1.
- While follow-up X-rays might eventually show periosteal reaction or callus formation if a fracture is present, this would only be visible weeks after the injury and wouldn't provide the immediate diagnostic information needed for proper treatment planning.
- MRI can detect bone bruising and stress reactions that would never appear on X-rays, which is crucial for guiding treatment and minimizing the risk of growth disturbances or chronic ankle instability 1.
- The American College of Radiology recommends MRI as the reference standard for ligamentous injury and assessment of stability, particularly in athletes 1.
Imaging Modalities
- Radiography is indicated as the initial imaging study, but it has limitations in detecting certain types of fractures and soft tissue injuries 1.
- Ultrasound may be useful but is not typically considered the first line of imaging for the evaluation of acute trauma to the ankle with positive OAR criteria 1.
Clinical Considerations
- Early and accurate diagnosis with MRI is important to guide appropriate treatment and minimize the risk of growth disturbances or chronic ankle instability in adolescent patients with suspected growth plate injuries.
- The presence of bone bruise and adjacent soft-tissue edema has shown a higher association with acute ligamentous injuries and tendon abnormalities, which can be detected by MRI 1.
From the Research
Imaging for Suspected Salter-Harris Type 1 Fracture
- Spaced x-rays may not show anything that an MRI does not in a 14-year-old male with a suspected Salter-Harris type 1 fracture of the distal fibular physis, as the growth plate is not visible on initial x-ray 2, 3.
- MRI is more sensitive than x-rays in detecting injuries to the growth plate and surrounding soft tissues, including the Anterior Talofibular Ligament (ATFL) and Calcaneofibular Ligament (CFL) 4, 5.
Diagnosis and Treatment of Salter-Harris Type 1 Fracture
- Salter-Harris type 1 fractures are classified as fractures through the growth plate, and most such fractures heal without permanent deformity 2.
- However, some Salter-Harris type 1 fractures may be complicated by growth arrest and subsequent deformity, especially if not managed properly 3, 5.
- Displaced Salter-Harris type 1 distal fibula fractures may require operative treatment to achieve anatomic reduction and prevent premature physeal closure, fibular growth disturbance, syndesmotic instability, and medial (deltoid ligament) injury 6.
Importance of Imaging in Diagnosis and Treatment
- Radiographic images are essential for prompt diagnosis and to minimize negative health outcomes in patients with Salter-Harris fractures 5.
- MRI can provide additional information on the extent of the injury and guide treatment decisions, especially in cases where the growth plate is not visible on initial x-ray 4, 5.