From the Guidelines
Bone bruises are often misdiagnosed as Salter-Harris type I fractures on MRI due to similar imaging characteristics, highlighting the need for careful correlation with clinical findings and consideration of the patient's age and skeletal maturity. The confusion arises because bone bruises show edema and hemorrhage within the bone marrow that can mimic the appearance of a growth plate injury, as noted in studies such as 1. On MRI, both conditions display increased signal intensity on T2-weighted and STIR sequences, particularly near the growth plate. The key difference is that a true Salter-Harris I fracture involves a complete separation through the physis (growth plate), while a bone bruise represents microtrabecular fractures with intact overall bone structure.
Some key points to consider in differentiating between bone bruises and Salter-Harris fractures include:
- Growth plates in children are naturally hyperintense on T2-weighted images, making subtle differences difficult to appreciate 1.
- Limited clinical history provided to radiologists can contribute to misdiagnosis, as both injuries often result from similar mechanisms of trauma.
- Accurate diagnosis requires correlation with clinical findings, consideration of the patient's age and skeletal maturity, and sometimes follow-up imaging to assess healing patterns.
- The use of in-phase and out-of-phase MRI sequences appears to be more reliable in differentiating benign stress fractures from pathologic fractures, which may also be applicable in distinguishing bone bruises from Salter-Harris fractures 1.
Given the potential for misdiagnosis and the importance of accurate diagnosis for guiding treatment, it is essential to approach MRI findings with caution and consider the clinical context, patient demographics, and the potential for both bone bruises and Salter-Harris fractures to present with similar imaging characteristics. This is particularly important in the pediatric population, where Salter-Harris fractures may require immobilization to prevent growth disturbances, while bone bruises typically heal with conservative management 1.
From the Research
Misdiagnosis of Bone Bruises as Salter-Harris Type I Fractures
- A bone bruise is often misdiagnosed as a Salter-Harris type I fracture on an MRI due to the similarity in symptoms and imaging findings 2, 3.
- Studies have shown that the clinical diagnosis of Salter-Harris type I fracture is often incorrect, with MRI identifying ligamentous sprains and/or bony contusions instead 2, 3.
- The high false-positive rate of clinically suspected Salter-Harris type I fractures can be attributed to the fact that bone bruises and ligamentous lesions can present with similar symptoms, such as pain and swelling, making it challenging to diagnose accurately 2, 3.
Imaging Findings
- MRI is a useful tool in diagnosing bone bruises and distinguishing them from Salter-Harris type I fractures 2, 4.
- However, ultrasound may not be sufficient to diagnose Salter-Harris type I fractures, and its sensitivity and specificity are not well established 5.
- The use of MRI can help identify the underlying pathology, such as ligamentous sprains, bony contusions, or joint effusion, which can guide treatment and management 2, 3.
Clinical Implications
- The misdiagnosis of bone bruises as Salter-Harris type I fractures can have significant clinical implications, including unnecessary treatment and delayed recovery 2, 3.
- Accurate diagnosis and treatment of bone bruises and ligamentous lesions can help improve patient outcomes and reduce the risk of complications 2, 3.
- Further studies are needed to establish the diagnostic accuracy of imaging modalities, such as ultrasound, in diagnosing Salter-Harris type I fractures and distinguishing them from bone bruises 5.