From the Guidelines
For a suspected Salter-Harris type I fracture of the distal fibula physis in a 14-year-old male with a lateral ankle injury where the growth plate is not visible on initial x-ray, I recommend immobilization with a short leg cast or removable walking boot for 3-4 weeks. Initial management should include rest, ice, compression, and elevation (RICE protocol) as suggested by general management principles for ankle injuries 1. Despite normal x-rays, clinical suspicion should guide treatment as physeal injuries may not be radiographically apparent, especially considering that radiographs have a sensitivity of 92% to 99% for detecting ankle fractures, but may not always show growth plate injuries 1. Follow-up imaging in 7-10 days may reveal periosteal new bone formation confirming the diagnosis. After immobilization, gradual return to activities with physical therapy focusing on range of motion, strengthening, and proprioception exercises is recommended. These fractures typically have excellent outcomes with proper management, but require appropriate treatment to prevent growth disturbances. If symptoms persist or worsen, advanced imaging such as MRI may be necessary to evaluate the physis more thoroughly, as MRI is the reference standard for ligamentous injury and assessment of stability, and can help exclude Salter 1 fractures in the pediatric population 1. Parents should be counseled about the importance of completing the full treatment course to ensure proper healing of the growth plate. Key considerations in the management include:
- Clinical suspicion guiding treatment due to potential radiographic occult fractures
- The role of follow-up imaging for confirmation of the diagnosis
- The importance of proper immobilization and rehabilitation to prevent long-term morbidity and ensure the best possible outcome in terms of quality of life.
From the Research
Diagnosis of Suspected Salter-Harris Type 1 Fracture
- The diagnosis of a suspected Salter-Harris type 1 fracture of the distal fibula physis in a 14-year-old male with a lateral ankle injury, where the growth plate is not visible on initial X-ray, can be challenging 2.
- The Salter-Harris classification system aids in estimating both the prognosis and the potential for growth disturbance, and classifies growth plate fractures into five groups, including type I, fracture through the growth plate 2.
- However, studies have shown that the clinical diagnosis of Salter-Harris type 1 fracture of the distal fibula (SH1DF) is often incorrect, and that most children with radiograph-negative lateral ankle injuries actually have ligament injuries (sprains) or bone contusions rather than growth plate fractures 3, 4, 5.
- Magnetic Resonance Imaging (MRI) can be used to confirm the diagnosis of SH1DF, and has been shown to be more accurate than clinical diagnosis alone 3, 4, 5.
- In one study, none of the 18 patients with clinically suspected SH1DF had evidence of fibular growth plate injury on MRI, and instead had ligamentous sprains, bony contusions, or other abnormalities 5.
- Another study found that only 3.0% of children with radiograph-negative lateral ankle injuries had MRI-confirmed SH1DF, and that most children had ligament injuries or bone contusions 4.
Imaging and Diagnosis
- Initial X-rays may not show the growth plate, and further imaging such as MRI may be necessary to confirm the diagnosis 3, 4, 5.
- MRI can help to identify ligamentous sprains, bony contusions, and other abnormalities that may be present in children with radiograph-negative lateral ankle injuries 3, 4, 5.
- The use of MRI can help to reduce the risk of overtreatment and minimize the inconveniences and costs associated with unnecessary immobilization and orthopedic follow-up 4.