What is the treatment for a plantaris tendon rupture?

Treatment of Plantaris Tendon Rupture

Conservative management with relative rest, ice therapy, and progressive rehabilitation is the recommended treatment for plantaris tendon rupture, as it typically heals well without surgical intervention. 1

Diagnosis

Accurate diagnosis is essential before initiating treatment:

• Physical examination should include at least two of the following tests:

  • Palpation for a gap or defect in the posterior calf
  • Thompson/Simonds squeeze test
  • Assessment of ankle plantar flexion strength
  • Evaluation of passive ankle dorsiflexion 2

• Imaging considerations:

  • Plain radiography should be performed first to rule out bony abnormalities
  • MRI is the preferred advanced imaging with 95% sensitivity and specificity for definitive diagnosis
  • Ultrasound is an alternative with good specificity (94%) but lower sensitivity (58%) 3

Treatment Algorithm

Initial Management (0-7 days)

• Relative rest: Reduce activities that cause pain but avoid complete immobilization to prevent muscle atrophy 3
• RICE protocol:
  • Rest: Limit weight-bearing activities that cause pain
  • Ice: Apply for 10 minutes through a wet towel for acute pain relief
  • Compression: Use elastic bandage to reduce swelling
  • Elevation: Keep the leg elevated when possible 3, 1
• Pain management: NSAIDs (oral or topical) for pain control and anti-inflammatory effect 3

Rehabilitation Phase (1-4 weeks)

• Progressive exercises:

  • Begin with gentle tensile loading exercises to stimulate collagen production
  • Advance to eccentric strengthening exercises for the posterior calf muscles
  • Include stretching exercises for the posterior thigh muscles 3, 4

• Functional progression:

  • Gradually increase weight-bearing activities as pain allows
  • Implement balance and proprioceptive training
  • Monitor for pain response during activity progression 4

Return to Activity Phase (4-6 weeks)

• Sport-specific training:
  • Implement sport-specific exercises when basic rehabilitation is completed
  • Gradually increase intensity and duration of activities 4
• Return to full activity when:
  • Full pain-free range of motion is achieved
  • Normal strength is restored compared to the unaffected side
  • Functional testing shows return to baseline performance 4

Special Considerations

Differential Diagnosis

• Plantaris rupture can mimic deep vein thrombosis (DVT) on imaging, requiring careful differentiation 1
• When Achilles tendon rupture occurs, an intact plantaris can still cause some plantar flexion, potentially creating a confusing clinical picture 1

Monitoring and Follow-up

• Regular assessment of pain and function throughout rehabilitation
• Follow-up imaging may be considered for persistent symptoms 3

Common Pitfalls to Avoid

• Misdiagnosis as simple calf strain or DVT 1
• Overly aggressive early rehabilitation that may exacerbate symptoms 3
• Prolonged immobilization leading to muscle atrophy 3
• Injecting corticosteroids directly into the tendon substance (if considered for pain management) 3

The plantaris tendon is considered vestigial and its rupture typically has minimal functional consequences, allowing for good outcomes with conservative management in most cases 1, 5.