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 preferred diagnostic method over spaced X-rays. This recommendation is based on the most recent and highest quality study, which suggests that MRI is the reference standard for assessing stability and ligamentous injury, particularly in athletes 1. MRI provides superior visualization of the growth plate and can detect bone marrow edema and soft tissue injuries that may not be visible on X-rays.
In cases where the growth plate is invisible on initial X-ray, MRI can help exclude Salter 1 fractures in the pediatric population 1. Additionally, MRI can simultaneously evaluate both the physeal injury and associated ligament damage, which is critical for treatment planning and return to sport assessment. While spaced X-rays might eventually show periosteal reaction or callus formation if a fracture is present, this approach delays diagnosis and treatment.
The use of MRI also avoids radiation exposure, which is particularly important in pediatric patients. Treatment decisions for growth plate injuries require accurate diagnosis, as missed Salter-Harris fractures can lead to growth disturbances. Key benefits of MRI in this context include:
- High-resolution evaluation of tendons and ligaments to distinguish between tendinopathy, sprain, and partial or complete tears
- Detection of bone bruise and adjacent soft-tissue edema, which have a higher association with acute ligamentous injuries
- Ability to exclude Salter 1 fractures in the pediatric population
- Simultaneous evaluation of physeal injury and associated ligament damage.
From the Research
Diagnostic Methods for Salter-Harris Type 1 Fracture
The diagnosis of a Salter-Harris type 1 fracture of the distal fibular physis can be challenging, especially when the growth plate is not visible on initial x-ray. The preferred diagnostic method in such cases is Magnetic Resonance Imaging (MRI) rather than spaced x-rays.
Advantages of MRI
- MRI can detect injuries to the growth plate, ligaments, and bones that may not be visible on x-rays 2, 3, 4.
- MRI can help differentiate between Salter-Harris type 1 fractures and other types of injuries, such as ligamentous sprains and bony contusions 2, 3.
- Studies have shown that MRI-confirmed Salter-Harris type 1 fractures are rare in children with radiograph-negative lateral ankle injuries, and most children in this group have ligament injuries or sprains 3, 4.
Limitations of X-rays
- X-rays may not detect growth plate injuries or fractures, especially if the growth plate is not visible 2, 3.
- X-rays may not provide a clear diagnosis in cases where the fracture is not displaced or is only partially visible 5.
Clinical Implications
- The use of MRI can help reduce the risk of misdiagnosis and overtreatment of Salter-Harris type 1 fractures 4.
- MRI can help guide treatment decisions and ensure that children receive appropriate care for their injuries 4.
- The Salter-Harris classification system can aid in estimating the prognosis and potential for growth disturbance in children with growth plate injuries 6.