How should I interpret a non‑contrast ankle MRI showing mild Achilles peritendinitis and a low‑grade deltoid ligament sprain in a patient with three weeks of persistent right ankle pain and heel tenderness after a motor‑vehicle collision?

Interpretation of Your Ankle MRI Findings

Your MRI reveals two distinct soft-tissue injuries from the motor vehicle collision: mild Achilles peritendinitis and a low-grade deltoid ligament sprain, both of which are common post-traumatic injuries that typically respond well to conservative management without requiring surgical intervention. 1

Understanding Your Specific Findings

Achilles Peritendinitis

• The "mild soft tissue edema along Achilles tendon" indicates inflammation of the tissue surrounding the tendon (peritendinitis), not a tear of the tendon itself. 2
• The edema extending through subcutaneous fat along the dorsal calcaneus is consistent with inflammatory changes from repetitive stress or acute trauma. 2
• This finding suggests the tendon structure remains intact, which is prognostically favorable. 3

Deltoid Ligament Sprain

• The "mild signal in deltoid ligament" represents a Grade 1 sprain (stretching without complete fiber disruption). 4, 5
• The deltoid ligament is the primary medial ankle stabilizer, and low-grade sprains typically heal with conservative treatment. 4
• MRI is highly accurate for detecting these ligamentous injuries that would be invisible on plain radiographs. 1, 6

Why MRI Was the Right Test

MRI without contrast is the reference standard for evaluating persistent ankle pain after trauma when radiographs are negative or inconclusive, as it detects both occult fractures and soft-tissue injuries with superior sensitivity. 1

• In your case at 3 weeks post-injury, persistent pain warranted MRI evaluation to exclude occult fractures, bone contusions, cartilage injury, and characterize soft-tissue damage. 1
• Studies show MRI detects bone marrow edema patterns and soft-tissue injuries in 93.5% of patients with persistent post-traumatic joint pain and negative radiographs. 6
• The absence of bone marrow edema or fracture line on your MRI effectively rules out occult fracture, which is critical information. 1, 6

Clinical Management Algorithm

Immediate Treatment (Weeks 3-8)

Supervised physical therapy is the cornerstone of management and should be initiated immediately, as it reduces recurrence by 62% and accelerates recovery by approximately 4.2 days compared to immobilization. 7, 8

• Specific exercises to request from PT:

  • Proprioceptive training with ankle disk or balance board 7
  • Gastrocnemius-soleus stretching and strengthening 2
  • Graded eccentric loading exercises 7
  • Coordination and stability exercises 8

• Adjunctive measures:

  • Semi-rigid or lace-up ankle brace during weight-bearing activities 7, 8
  • Cryotherapy 20-30 minutes, 3-4 times daily (ice and water in damp cloth) 8
  • Elevation above heart level when resting 8
  • NSAIDs for pain control 2
  • Heel lifts (¼ to ½ inch) to reduce Achilles tension 2

Follow-up Timeline

• Re-evaluate at 6-8 weeks to assess response to physical therapy. 7
• Expected improvement timeline: partial ligament injuries typically show significant improvement within 6-8 weeks with proper supervised therapy. 8

Red Flags Requiring Earlier Return

Return immediately if any of the following develop: 7

• Increased swelling or inability to bear weight
• New mechanical symptoms (locking, catching, giving way)
• Failure to progress in physical therapy
• Significantly worsening pain

When to Consider Repeat Imaging

Repeat MRI is NOT indicated unless: 7

• New trauma occurs
• Symptoms significantly worsen despite appropriate therapy
• Clinical suspicion develops for osteochondral lesion (persistent mechanical symptoms)
• No improvement after 6-8 weeks of supervised physical therapy 7

Important Caveats

• Avoid prolonged immobilization: Early functional treatment with controlled motion produces superior outcomes compared to casting or prolonged rest. 7, 8
• Cryotherapy alone is insufficient: Ice provides minimal benefit for pain, swelling, or function when used as the sole treatment modality. 7
• Supervised PT is superior to home exercises: Unsupervised training has significantly worse outcomes than supervised physical therapy programs. 8
• The calcification mentioned in your heel tenderness may represent chronic changes or early healing response, but the absence of fracture on MRI is reassuring. 1

Prognosis

With appropriate supervised physical therapy and functional bracing, you should expect:

• Return to normal activities within 6-8 weeks for these mild injuries 8
• 62% reduction in recurrence risk with proper exercise therapy 8
• Return to work approximately 7 days sooner with functional treatment versus immobilization 8