What is the recommended MRI protocol for an elderly male with chronic right knee pain, without a history of injury, and negative X-ray, ultrasound, and CT scans?

MRI Protocol for Elderly Male with Chronic Knee Pain

Order an MRI of the right knee without IV contrast, as this is the standard and appropriate imaging study for chronic knee pain when initial radiographs are negative or show only joint effusion. 1, 2, 3

Standard MRI Protocol

MRI without intravenous contrast is the recommended examination for evaluating chronic knee pain in this clinical scenario. 1 This protocol effectively identifies:

• Bone marrow lesions (BMLs) that correlate with knee pain, particularly in elderly males 1, 2
• Subchondral insufficiency fractures, which are common in elderly patients and often appear normal on initial radiographs 1
• Articular cartilage abnormalities using standard sequences or quantitative T2 mapping 1, 2
• Meniscal pathology, though tears are often incidental findings in patients over 70 years 1
• Joint effusion extent and synovitis 1
• Popliteal cyst presence or rupture 1

Why Non-Contrast MRI Is Sufficient

The American College of Radiology explicitly states that MRI without IV contrast is more sensitive than radiography and is usually the next indicated examination when initial radiographs are normal or reveal only joint effusion. 1 Non-contrast sequences adequately visualize all relevant pathology in this age group, including:

• Subchondral cysts 1
• Stress fractures 1
• Tendon pathology 3
• Osteochondritis dissecans and loose bodies 1, 3

When to Consider Adding Contrast

Do NOT order contrast-enhanced MRI initially. 1 Contrast should only be added if the non-contrast study reveals findings requiring further characterization of specific inflammatory conditions:

• Hoffa's disease (enhancing synovitis >2mm in Hoffa's fat correlating with peripatellar pain) 1, 2
• Deep infrapatellar bursitis 1, 2
• Patellofemoral friction syndrome 1, 2
• Adhesive capsulitis 1, 2
• Pigmented villonodular synovitis requiring extent quantification 1, 2, 3

Critical Clinical Context for Elderly Males

In elderly males specifically, bone marrow lesions on MRI are strongly associated with knee pain, especially with family history of osteoarthritis. 1 Recent research demonstrates that MRI alters management in approximately 24% of patients over 60 years with chronic knee pain, with the highest yield (70%) in patients with minimal osteoarthritis (Kellgren-Lawrence grade 0-1). 4

Subchondral insufficiency fractures are particularly important to identify as they commonly involve the medial femoral condyle in middle-aged to elderly patients and can progress to articular collapse requiring total knee arthroplasty if unrecognized. 1

Common Pitfalls to Avoid

• Never order MRI without recent radiographs (within the past year), as approximately 20% of chronic knee pain patients inappropriately receive MRI without prior radiographs 1
• Do not order MRI with contrast as the initial study unless there is specific clinical suspicion for inflammatory synovial pathology 1, 2
• Recognize that meniscal tears in patients over 70 years are often asymptomatic incidental findings and may not explain the pain 1
• Consider hip radiographs if knee imaging is unremarkable, as referred pain from hip pathology must be excluded in elderly patients with negative knee studies 1

Alternative Considerations

MR arthrography is NOT indicated for this patient, as it is reserved for patients with prior meniscal surgery, known chondral lesions, or suspected loose bodies. 2, 3

CT arthrography could be considered if MRI is contraindicated, as it can evaluate menisci and articular cartilage with sensitivities and specificities of 86-100%. 1