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 diagnose a potential fracture and displacement, especially when the growth plate is not visible on initial x-ray. 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 important in athletes and adolescents 1. The study highlights that MRI can directly visualize the growth plate injury, detect bone marrow edema, and evaluate associated soft tissue injuries, including ligament damage that X-rays cannot show.
When considering the diagnosis of a Salter-Harris type 1 fracture, it is essential to note that initial X-rays may miss these injuries since they occur through the physis without displacing bone fragments, making the growth plate appear normal or "invisible" on X-ray despite the injury 1. MRI, on the other hand, provides superior assessment of physeal injuries, can detect early signs of growth arrest, and helps guide appropriate treatment decisions. This is particularly important in adolescents near skeletal maturity where growth plate injuries can lead to complications if missed or improperly managed.
Key benefits of using MRI in this context include:
- Direct visualization of the growth plate injury
- Detection of bone marrow edema
- Evaluation of associated soft tissue injuries, including ligament damage
- Superior assessment of physeal injuries compared to X-rays
- Ability to detect early signs of growth arrest and guide treatment decisions 1.
From the Research
Diagnostic Imaging Modalities
To diagnose a potential fracture and displacement in a 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, the following diagnostic imaging modalities can be considered:
- Spaced x-rays: This modality may not be sufficient to diagnose a Salter-Harris type 1 fracture, as the growth plate is not visible on initial x-ray 2, 3.
- Magnetic Resonance Imaging (MRI): MRI is a more sensitive modality for diagnosing Salter-Harris type 1 fractures, as it can detect injuries to the growth plate and surrounding tissues 2, 3.
Advantages of MRI
The advantages of using MRI to diagnose Salter-Harris type 1 fractures include:
- High sensitivity for detecting growth plate injuries 2, 3.
- Ability to detect ligamentous sprains and bony contusions, which are common in children with radiograph-negative lateral ankle injuries 2, 3.
- Non-invasive and does not involve ionizing radiation 2, 3.
Case Studies
Several case studies have demonstrated the effectiveness of MRI in diagnosing Salter-Harris type 1 fractures:
- A study of 18 patients with suspected Salter-Harris type 1 fractures of the distal fibula found that none of the patients had evidence of fibular growth plate injury on MR imaging, but instead had ligamentous sprains and bony contusions 2.
- A study of 135 children with radiograph-negative lateral ankle injuries found that only 4 (3.0%) had MRI-confirmed Salter-Harris type 1 fractures of the distal fibula, while 108 (80.0%) had ligament injuries and 27 (22.0%) had isolated bone contusions 3.
- A case report of a 16-year-old boy with a Salter-Harris type 1 injury of the proximal tibial physis demonstrated the effectiveness of early closed reduction and fixation in achieving excellent long-term results 4.
- A case report of a patient with a self-inflicted Salter-Harris type 1 fracture of the distal femur highlighted the importance of considering epiphyseal fractures in pediatric patients with uncertain limb swelling 5.
- A study of two cases of displaced Salter-Harris type 1 distal fibula fractures demonstrated the effectiveness of operative treatment in achieving excellent outcomes 6.