From the Research
A Salter-Harris type I fracture is difficult to diagnose on MRI primarily because it involves a clean separation through the growth plate (physis) without extending into the adjacent bone, and the growth plate's normal appearance on MRI can mask subtle disruptions within it. This type of fracture presents a diagnostic challenge on MRI because the growth plate itself is already a distinct structure with different signal characteristics from surrounding bone, making subtle disruptions within it hard to detect 1. The growth plate normally appears as a high signal intensity band on T2-weighted images, and when fractured, there may be minimal displacement or edema that can be easily overlooked. Additionally, the normal undulating appearance of the growth plate and its variable thickness throughout development can mask subtle abnormalities. MRI is generally more sensitive for detecting bone marrow edema and soft tissue injuries rather than the clean separations characteristic of Salter-Harris I fractures.
Some key points to consider when diagnosing Salter-Harris type I fractures on MRI include:
- The growth plate's normal appearance on MRI can make it difficult to detect subtle disruptions within it 1
- Minimal displacement or edema may be present in Salter-Harris type I fractures, making them hard to detect on MRI
- Clinical examination findings such as point tenderness over the growth plate, combined with plain radiographs (especially stress views or comparison views with the uninjured side) are often more reliable for diagnosis
- Follow-up imaging after 7-10 days may reveal periosteal new bone formation that confirms the diagnosis retrospectively. However, a more recent study from 2024 highlights the importance of prompt initiation of physical rehabilitation following such injuries, and the use of MRI to identify concomitant injuries such as ACL tears 2.
It's also important to note that the diagnosis of Salter-Harris type I fractures can be influenced by the presence of concomitant injuries, such as ligamentous sprains and bony contusions, which can be detected on MRI 1. In fact, a study from 2010 found that in cases of suspected Salter-Harris type I fractures, MRI often identified ligamentous sprains and/or bony contusions instead of the fracture itself 1. Therefore, a comprehensive diagnostic approach that includes clinical examination, plain radiographs, and MRI is necessary to accurately diagnose Salter-Harris type I fractures.