From the Guidelines
The best way to diagnose a suspected Salter-Harris type 1 fracture of the distal fibula physis in a 14-year-old male is to obtain an MRI of the ankle, as it is the reference standard for ligamentous injury and assessment of stability, and can help exclude Salter 1 fractures in the pediatric population. When the growth plate is not visible on X-ray and there is tenderness to palpation at the lateral malleoli, anterior talofibular ligament (ATFL), and calcaneofibular ligament (CFL), an MRI is particularly useful as it can directly visualize the cartilaginous physis and detect bone marrow edema that indicates injury 1. Some key points to consider in this diagnosis include:
- MRI is the gold standard for evaluating growth plate injuries and ligamentous injuries, allowing for distinction between tendinopathy, sprain, and partial or complete tears 1
- The presence of bone bruise and adjacent soft-tissue edema have shown a higher association with acute ligamentous injuries and tendon abnormalities, even in patients with negative radiographs 1
- MRI can provide a comprehensive evaluation of both the growth plate and soft tissue structures, which is critical in athletes for treatment planning and return to sport assessment 1
- Other imaging options, such as CT scanning and ultrasound, have limitations, including radiation exposure and operator dependence, respectively In the interim, the ankle should be immobilized in a removable boot or splint, with weight-bearing as tolerated if pain allows, to prevent further injury and promote healing. Prompt diagnosis is important as missed physeal injuries can lead to growth disturbances, though distal fibular physeal injuries generally have good outcomes with appropriate management.
From the Research
Diagnosis of Suspected Salter-Harris Type 1 Fracture
To diagnose a suspected Salter-Harris type 1 fracture of the distal fibula physis in a 14-year-old male with a right lateral ankle injury, the following steps can be considered:
- The patient's symptoms, such as tenderness to palpation (TP) at the lateral malleoli, anterior talofibular ligament (ATFL), and calcaneofibular ligament (CFL), should be evaluated 2, 3.
- Since the growth plate is not visible on X-ray, magnetic resonance imaging (MRI) can be used to confirm the diagnosis of a Salter-Harris type 1 fracture 3, 4.
- MRI can also help identify other potential injuries, such as ligamentous sprains, bone contusions, or joint effusions, which may be present in the absence of a Salter-Harris type 1 fracture 2, 3, 4.
Importance of MRI in Diagnosis
MRI is a crucial diagnostic tool in cases where a Salter-Harris type 1 fracture is suspected but not visible on X-ray. Studies have shown that MRI can help identify the true nature of the injury, which may not always be a Salter-Harris type 1 fracture 3, 4.
- In one study, none of the patients with a clinically suspected Salter-Harris type 1 fracture of the distal fibula had evidence of this injury on MRI 3.
- Another study found that only 3.0% of children with a clinically suspected Salter-Harris type 1 fracture of the distal fibula had MRI-confirmed evidence of this injury 4.
Potential Injuries in the Absence of a Salter-Harris Type 1 Fracture
In the absence of a Salter-Harris type 1 fracture, other potential injuries that may be present include:
- Ligamentous sprains: These are common in children with lateral ankle injuries and can be identified on MRI 3, 4.
- Bone contusions: These can also be identified on MRI and may be present in the absence of a Salter-Harris type 1 fracture 3, 4.
- Joint effusions: These can be present in cases of ligamentous sprains or other injuries, and can be identified on MRI 2, 3.