From the Guidelines
Yes, obtaining spaced X-rays in addition to an MRI is recommended for this 14-year-old male with a suspected Salter-Harris type 1 fracture of the distal fibular physis. The MRI is the reference standard for ligamentous injury and assessment of stability, particularly important for evaluating injuries to the Anterior Talofibular Ligament (ATFL) and Calcaneofibular Ligament (CFL), as it allows for high-resolution evaluation of tendons and ligaments to distinguish between tendinopathy, sprain, and partial or complete tears 1. However, spaced X-rays at 2-3 weeks post-injury can reveal periosteal new bone formation or physeal widening that may not have been visible on the initial X-ray, confirming the diagnosis of a Salter-Harris injury.
Key points to consider in this case include:
- The importance of MRI in assessing ligamentous injuries, which can occur without fracture on radiography 1
- The potential for MRI to help exclude Salter 1 fractures in the pediatric population 1
- The value of spaced X-rays in monitoring proper healing and alignment, and detecting potential complications such as premature growth arrest 1
- The complementary information provided by both imaging modalities, with MRI offering immediate detailed assessment of bone and soft tissue injuries, and spaced X-rays providing a cost-effective way to monitor healing progression and long-term outcomes in this skeletally immature patient.
Given the potential for ligamentous injuries to occur without fracture on radiography, and the importance of monitoring healing progression and long-term outcomes in a skeletally immature patient, the combination of MRI and spaced X-rays is the most appropriate approach. This approach prioritizes the patient's morbidity, mortality, and quality of life by ensuring accurate diagnosis and monitoring of the injury, and allowing for timely intervention if complications arise.
From the Research
Need for Spaced X-rays in Addition to MRI
- The provided studies do not directly address the need for spaced x-rays in addition to an MRI for a 14-year-old male with a suspected Salter-Harris type 1 fracture of the distal fibular physis 2, 3, 4, 5, 6.
- However, it is mentioned that physeal injuries may not be initially obvious in children who present with periarticular trauma, and a high index of suspicion is important for diagnosis 2.
- The Salter-Harris classification of growth plate injuries aids in estimating both the prognosis and the potential for growth disturbance 3.
- In some cases, MRI is advocated to better delineate the fracture as the potential complications can be limb threatening 6.
Diagnosis and Management of Salter-Harris Fractures
- Salter-Harris I & Salter-Harris II growth plate fractures are commonly managed by closed manipulation, reduction & immobilization 2.
- Physeal fractures can have many complications such as malunion, bar formation, acceleration of growth of physis, posttraumatic arthritis, ligament laxity and shortening of the bone 2.
- The key to well-healing fractures is successful anatomic reduction and patients must have regular follow-up for these injuries 2.
- In cases where the growth plate is not visible on initial x-ray, further testing such as MRI may be necessary to better diagnose the injury 6.
Concern for Injury to the Anterior Talofibular Ligament (ATFL) and Calcaneofibular Ligament (CFL)
- The provided studies do not specifically address the concern for injury to the ATFL and CFL in the context of a Salter-Harris type 1 fracture of the distal fibular physis.
- However, it is mentioned that differential diagnosis for a Salter-Harris fracture includes a ligamentous sprain, acute osteomyelitis, or an extraphyseal fracture such as a Torus fracture 2.