From the Guidelines
Spaced X-rays are the recommended initial imaging modality for diagnosing a suspected Salter-Harris fracture of the distal fibular physis in a 14-year-old male with a right lateral ankle injury, as they provide adequate diagnostic information while being less costly and involving less radiation than other imaging modalities. According to the American College of Radiology Appropriateness Criteria, radiographs are indicated as the initial imaging study in patients who meet the Ottawa Ankle Rules (OAR) criteria, with a sensitivity of 92-99% for detecting ankle fractures 1. The typical radiographic protocol includes three standard views: anteroposterior, lateral, and mortise views, which can help identify fractures and assess stability.
In the context of pediatric ankle injuries, spaced X-rays can reveal subtle fractures and ligamentous injuries that might not be visible on standard views. While MRI offers superior soft tissue visualization, it is typically reserved for cases where X-rays are inconclusive or when there's concern for complex ligamentous injury or osteochondral lesions. The use of weight-bearing radiographs, if possible, can provide important information on fracture stability, which is crucial in the treatment of malleolar fractures 1.
Key considerations in the diagnosis of Salter-Harris fractures include:
- The Ottawa Ankle Rules (OAR) criteria, which can help identify patients who require imaging
- The use of standard radiographic views, including anteroposterior, lateral, and mortise views
- The potential for spaced X-rays to reveal subtle fractures and ligamentous injuries
- The importance of assessing fracture stability, particularly in cases where weight-bearing radiographs are possible
- The role of MRI in cases where X-rays are inconclusive or when there's concern for complex ligamentous injury or osteochondral lesions.
Overall, spaced X-rays represent a reasonable and cost-effective approach for diagnosing suspected Salter-Harris fractures of the distal fibular physis in pediatric patients, as they can provide adequate diagnostic information while minimizing radiation exposure and cost 1.
From the Research
Diagnosis of Salter-Harris Fracture
- Spaced x-rays are recommended over Magnetic Resonance Imaging (MRI) for diagnosing a suspected Salter-Harris fracture of the distal fibular physis in a 14-year-old male with a right lateral ankle injury due to the following reasons:
Comparison of Imaging Modalities
- A study by 2 found that Salter-Harris I fractures of the distal fibula are rare in children with radiograph-negative lateral ankle injuries, and these children most commonly have ligament injuries (sprains), sometimes associated with radiographically occult avulsion fractures.
- Another study by 3 reported that the most common injuries of the pediatric ankle are ATFL sprain and osteochondral avulsions, rather than Salter-Harris fractures.
Limitations of MRI
- While MRI can be useful in detecting occult fractures, a study by 4 found that plain x-rays can be deceptive in detecting fracture displacement, and MRI or CT scans may be necessary to accurately assess the extent of the injury.
- However, in the context of a suspected Salter-Harris fracture of the distal fibular physis, spaced x-rays may be sufficient for initial diagnosis, and MRI may not be necessary unless there are concerns about occult fractures or ligament injuries.
Clinical Considerations
- A study by 5 highlighted the importance of timely diagnosis and management of ankle injuries in adolescents to optimize outcomes and avoid complications.
- Another study by 6 found that open reduction and internal fixation can be an effective treatment for displaced Salter-Harris type II fractures of the distal tibia, but premature physeal closure is a common complication.