Can you interpret the MRI of a 35-year-old male with progressive right foot pain localized under the second toe, worsened by walking and toe dorsiflexion, and no clear inciting injury?

Can a PCP Interpret the MRI for This Forefoot Pain?

Yes, as a primary care physician you can and should interpret the MRI for this patient's forefoot pain localized under the second toe, focusing on specific pathologies that match the clinical presentation: plantar plate tear, Morton's neuroma, intermetatarsal bursitis, stress fracture, and Freiberg's infraction.

Why MRI is Appropriate Here

The ACR Appropriateness Criteria 1 explicitly state that MRI is usually appropriate as the next imaging study after negative or equivocal radiographs in patients with chronic forefoot pain. Your patient has progressive pain over 2 months localized under the second toe, worsened by walking and toe dorsiflexion—this clinical picture warrants MRI evaluation.

What to Look for on the MRI

Priority #1: Plantar Plate Tear

• Why this matters most: Pain under the second toe worsened by dorsiflexion is the classic presentation
• MRI findings: Look for discontinuity or increased signal in the plantar plate at the second MTP joint on T2-weighted or STIR sequences
• Accuracy: MRI has 95% sensitivity and 100% specificity for plantar plate tears 1
• Clinical correlation: The second ray is most commonly affected, and your patient's symptoms fit perfectly

Priority #2: Morton's Neuroma

• Location: Check the second-third intermetatarsal space (though third-fourth is more common)
• MRI findings: Dumbbell-shaped mass on coronal images, hypointense on T1, variable on T2
• Sensitivity: 93% for MRI 1
• Note: Recent evidence shows intermetatarsal bursitis (IMB) is actually more common than Morton's neuroma in patients with intermetatarsal pain (53.8% vs 19.2%) 2, so look for fluid-filled bursa as well

Priority #3: Stress Fracture

• Why consider: Gradual onset over months, no clear injury, progressive worsening
• MRI findings: Bone marrow edema in second metatarsal shaft or neck on STIR/T2, with or without cortical break
• Advantage: MRI is far superior to radiographs (which have only 12-56% sensitivity for stress fractures) 1

Priority #4: Freiberg's Infraction

• What it is: Avascular necrosis of the metatarsal head (second most common)
• MRI findings: Subchondral signal changes, flattening of metatarsal head, joint effusion 1

Practical Interpretation Algorithm

Step 1: Examine the plantar plate at the second MTP joint on sagittal and coronal sequences

• Intact and normal thickness = unlikely source
• Tear or thickening with high T2 signal = likely diagnosis

Step 2: Assess the second metatarsal bone marrow on STIR/T2

• Diffuse edema pattern = stress reaction or fracture
• Subchondral changes in head = Freiberg's infraction
• Normal = look elsewhere

Step 3: Check the second-third intermetatarsal space

• Mass-like lesion = Morton's neuroma
• Fluid collection = intermetatarsal bursitis
• Both can cause similar symptoms 2

Step 4: Look for secondary findings

• Joint effusion at second MTP
• Soft tissue edema plantar to second metatarsal head
• Synovitis

Critical Pitfalls to Avoid

1. Don't overcall plantar fasciitis: Your patient has pain under the second toe, not the heel. MRI findings of plantar fasciitis can be seen in asymptomatic patients 1

2. Don't confuse normal bursa with pathology: Normal intermetatarsal bursas can be visible on MRI as small fluid collections 2

3. Correlate with clinical exam: The location of maximal tenderness should match the MRI findings. Pain with second toe dorsiflexion specifically suggests plantar plate pathology

4. Beware of incidental findings: Bone marrow edema can occur in asymptomatic feet 3

When to Refer

• Definite plantar plate tear: Orthopedic or podiatry referral for potential surgical repair if conservative management fails
• Freiberg's infraction: May require surgical debridement in advanced cases
• Stress fracture: Most can be managed conservatively with offloading, but non-union may need referral
• Morton's neuroma: Consider referral if injection therapy fails

Immediate Management While Awaiting MRI Results

Given the clinical picture strongly suggests plantar plate pathology:

• Footwear modification: Rigid-soled shoes or carbon fiber inserts to limit MTP dorsiflexion
• Metatarsal pad: Placed proximal to second metatarsal head to offload pressure
• Avoid flat shoes and Crocs: These allow excessive MTP motion
• The meloxicam trial is reasonable: If inflammation is present, symptoms may improve, but this won't heal a structural tear

The trial of meloxicam (taken 2+ hours away from colestipol to avoid binding) can help differentiate inflammatory from mechanical causes, but don't let symptom improvement with NSAIDs delay definitive imaging—plantar plate tears require specific treatment to prevent progression to dislocation of the second toe.