From the Guidelines
Radiologists and pediatric orthopedic surgeons may interpret ankle MRIs differently due to their distinct training and clinical perspectives, with the radiologist's diagnosis of a Salter-Harris type I growth plate fracture potentially being more accurate than the orthopedic specialist's diagnosis of a bone bruise, as MRI is the reference standard for ligamentous injury and assessment of stability 1.
When interpreting ankle MRIs, radiologists and pediatric orthopedic surgeons bring different areas of expertise to the table. The radiologist's diagnosis of a Salter-Harris type I growth plate fracture is based on the imaging findings, which can be subtle, showing only widening of the growth plate without obvious bone displacement. On the other hand, the orthopedic specialist's diagnosis of a bone bruise may be influenced by their clinical examination findings, patient symptoms, and direct assessment of ankle stability, which radiologists don't have access to when interpreting images.
Some key points to consider in this scenario include:
- MRI is the reference standard for ligamentous injury and assessment of stability, particularly important in athletes 1
- Ligament and tendon injuries can occur without fracture on radiography, and the presence of bone bruise and adjacent soft-tissue edema have shown a higher association with acute ligamentous injuries and tendon abnormalities 1
- MRI can also help exclude Salter 1 fractures in the pediatric population, which may appear similar to bone bruises on imaging 1
- The orthopedic surgeon's specialized experience with pediatric bone injuries and clinical presentation may weigh more heavily than imaging alone in their diagnosis
Given the potential for differing interpretations, it is essential to consider the radiologist's diagnosis of a Salter-Harris type I growth plate fracture as the more accurate diagnosis, as it is based on the reference standard for ligamentous injury and assessment of stability 1. This difference in diagnosis could impact treatment decisions, as fractures might require immobilization while bone bruises may be managed with less restrictive approaches. When faced with differing interpretations, additional imaging or follow-up studies might be warranted to clarify the diagnosis.
From the Research
Differences in Interpretation
- Radiologists and pediatric orthopedic surgeons may interpret ankle MRIs differently due to varying levels of expertise and familiarity with growth plate injuries 2, 3.
- The Salter-Harris classification system is used to estimate the prognosis and potential for growth disturbance in growth plate injuries, but its application may vary between radiologists and orthopedic surgeons 2.
Diagnosis of Salter-Harris I Fracture
- A Salter-Harris I fracture is a fracture through the growth plate, but recent studies suggest that sprains may be more common than previously thought in children with radiograph-negative lateral ankle injuries 3, 4.
- MRI evidence has shown that many cases diagnosed as Salter-Harris I fractures may actually be ligamentous sprains or bony contusions 3, 4.
Role of MRI in Diagnosis
- MRI can provide direct visualization of cartilage and improve the evaluation of growth plate injury, allowing for the detection of occult fractures and alteration of Salter-Harris staging 5.
- MRI can also result in a change in patient management, particularly when diagnostic uncertainty persists following the evaluation of conventional radiographs 5.
Clinical Implications
- The diagnosis of a Salter-Harris I fracture may lead to immobilization and orthopedic follow-up, while a diagnosis of a bone bruise or ligamentous sprain may result in a different treatment approach 3, 4.
- Understanding the unique anatomy of the skeletally immature ankle and the mechanism of injury is critical to the diagnosis and treatment of physeal fractures of the distal tibia and fibula 6.