Understanding the Difference Between Tendinosis and Tendonitis in the Foot and Ankle

If you're experiencing foot or ankle pain, particularly around the tendons, you've likely heard the terms tendonitis and tendinosis. While these two conditions affect tendons and may present with similar symptoms, they are fundamentally different in their causes, pathology, and treatment approaches. Understanding these differences is crucial for appropriate management and recovery.

What Are Tendonitis and Tendinosis?

Tendonitis:
  - Also known as acute tendinitis.
  - Refers to inflammation of a tendon caused by sudden injury, overuse, or strain.
  - Typically develops over days or weeks.
  - Common symptoms include pain, swelling, warmth, and tenderness around the affected tendon.
  - The inflammatory response involving increased blood flow and inflammatory cells.

- Tendinosis:
  - Also called chronic tendinopathy.
  - Represents a degenerative process within the tendon tissue due to repetitive stress and micro-tears.
  - Usually develops over months or even years.
  - Symptoms include persistent pain, stiffness, and sometimes a thickened or nodular appearance of the tendon.
  - No active inflammation is present; instead, there are degenerative changes.

Key Differences in Pathology

Tendonitis:

Nature: Inflammatory

Histology: inflammatory cells, edema

Onset: Sudden, rapid

Tendinosis:

Nature: Degenerative/chronic

Histology: Collagen degeneration, fiber disorganization, lack of inflammatory cells

Onset: Gradual and chronic

Common Causes and Risk Factors

Tendonitis:
  - Sudden increase in activity or intensity.
  - Overuse, improper footwear.
  - Acute trauma.

Tendinosis:
  - Repetitive microtrauma.
  - Overuse without adequate rest.
  - Age-related degeneration.
  - Poor biomechanics or alignment issues.

Common Tendons Affected in the Foot and Ankle

- Achilles tendon.
- Posterior tibial tendon.
- Peroneal tendons.
- Extensor tendons.

Note: Both conditions can affect these tendons, but their management differs.


Diagnosis

Diagnosis involves clinical examination and imaging:

Physical Exam:
  - Tenderness, swelling, and pain on movement.
  - Point tenderness over the tendon.

Imaging:
  - Ultrasound:
    - Can detect inflammation (tendonitis) or degenerative changes (tendinosis).
  - MRI:
    - Provides detailed assessment of tissue integrity.

Treatment Approaches

Tendonitis:
  - Rest and activity modification.
  - Ice application to reduce inflammation.
  - Non-steroidal anti-inflammatory drugs (NSAIDs).
  - Physical therapy focusing on gentle stretching and strengthening.
  - Sometimes corticosteroid injections (with caution).

Tendinosis:
  - Rest and avoiding aggravating activities.
  - Eccentric exercises to promote collagen remodeling.
  - Physical therapy emphasizing load management.
  - Nutritional support with supplements like collagen if appropriate.
  - Less responsive to NSAIDs; focus on regenerative therapies.

When to Seek Medical Advice

Persistent foot or ankle pain that lasts more than a few days, worsens, or interferes with daily activities warrants consultation with a podiatrist. Proper diagnosis ensures targeted treatment—whether anti-inflammatory measures for tendonitis or regenerative strategies for tendinosis.

Conclusion

Understanding whether you are dealing with a tendonitis or tendinosis can significantly influence your treatment plan and prognosis. While tendonitis involves active inflammation and often responds well to anti-inflammatory treatments, tendinosis is a degenerative condition requiring different therapeutic strategies focused on tissue regeneration. 

If you're experiencing persistent tendon pain in your foot or ankle, schedule an appointment with Dr. Gireesh Reddy or Dr. Sirisha Pokala at Restore Foot & Ankle Specialists by calling (469) 573-3427 or by booking an appointment online.