Should an MRI with or without contrast be ordered for an acute nondisplaced patellar fracture with soft tissue swelling and suprapatellar joint effusion?

From the Guidelines

For a patient with an acute nondisplaced patellar fracture with soft tissue swelling and suprapatellar joint effusion, I recommend ordering an MRI without contrast. This recommendation is based on the American College of Radiology's (ACR) appropriateness criteria for acute trauma to the knee, which suggests that MRI knee without IV contrast is usually appropriate as the next imaging study after radiographs did not show fracture, for the evaluation of suspected occult knee fractures or internal derangement after a fall or acute twisting trauma to the knee 1. The non-contrast MRI will provide excellent visualization of bone marrow edema, fracture lines, cartilage integrity, and any associated soft tissue injuries such as ligament or tendon damage.

Some key points to consider in this clinical scenario include:

• The presence of soft tissue swelling and suprapatellar joint effusion, which can be adequately visualized on a non-contrast MRI
• The ability of non-contrast MRI to demonstrate joint effusion and soft tissue swelling without the need for contrast enhancement
• The potential complications associated with contrast administration, such as allergic reactions or concerns about gadolinium retention, which can be avoided with a non-contrast study

In this case, the primary concern is the acute traumatic fracture, and the non-contrast MRI provides the necessary diagnostic information to guide treatment decisions. Contrast would be more appropriate if there were concerns about infection, tumor, or synovial pathology, which are not the primary concerns in this clinical scenario. Therefore, an MRI without contrast is the most appropriate imaging study for this patient.

From the Research

Diagnosis and Imaging for Patella Fractures

• For a patient with an acute nondisplaced fracture involving the patella, soft tissue swelling, and suprapatellar joint effusion, the primary concern is to assess the extent of the injury and determine the appropriate treatment plan.
• The provided studies do not directly address the use of MRI with or without contrast for diagnosing patella fractures. However, they do discuss the importance of accurate diagnosis and treatment planning for patella fractures.

Treatment Planning for Patella Fractures

• According to 2, treatment for patella fractures can be conservative or surgical, depending on the type of fracture. Undisplaced fractures with an intact extensor mechanism can be treated nonoperatively.
• Surgical treatment is recommended for fractures that disrupt the extensor mechanism or have more than 2 to 3 mm of step-off and more than 1 to 4 mm of displacement 3, 2.

Role of Imaging in Patella Fractures

• Computed tomography (CT) of the knee can provide a better understanding of the fracture complexity and modify treatment plans 2.
• Magnetic Resonance Imaging (MRI) can be useful in detecting soft tissue injuries, such as medial patellofemoral ligament (MPFL) tears and chondral damage, which are common after acute patellar dislocation 4.
• However, there is no direct evidence to suggest that MRI with or without contrast is necessary for diagnosing acute nondisplaced patella fractures with soft tissue swelling and suprapatellar joint effusion.

Soft Tissue Injuries and Patella Fractures

• Soft tissue swelling and suprapatellar joint effusion can be associated with patella fractures, and accurate diagnosis is crucial for treatment planning 5, 6.
• The presence of suprapatellar plicae can lead to joint compartmentalization and distention of the suprapatellar bursa, manifesting as a soft-tissue mass 6.