Plantar Fasciitis: Inflammation or Degeneration of the Fascia?

Plantar fasciitis is a common condition among runners and athletes, characterized by pain in the heel and along the arch of the foot. Traditionally, plantar fasciitis has been thought of as an inflammatory condition due to its suffix "-itis," which implies inflammation. However, recent research suggests that the pain might stem more from degeneration of the fascia than from inflammation itself. Understanding whether plantar fasciitis is driven by inflammation or degeneration can shape more effective treatment approaches.

What is Plantar Fasciitis?

Plantar fasciitis refers to pain caused by injury to the plantar fascia, a thick, fibrous band of connective tissue that runs from the heel bone (calcaneus) to the base of the toes. This structure is responsible for supporting the arch of the foot and absorbing shock during activities like running or walking. When the plantar fascia becomes overloaded due to factors like poor biomechanics, overuse, or tight calf muscles, it can lead to microtears, causing pain near the heel.

Inflammation vs. Degeneration: What’s Really Happening?

For many years, plantar fasciitis was primarily considered an inflammatory condition. However, recent histological studies (examinations of tissue under a microscope) have challenged this assumption. Instead of classic signs of inflammation (e.g., immune cell infiltration, swelling), these studies have revealed more evidence of degeneration within the fascia.

1. Degenerative Changes in the Fascia Histological research shows that in many cases of chronic plantar fasciitis, the tissue appears degenerated rather than inflamed. A study by Lemont et al. (2003) analyzed 50 cases of chronic plantar fasciitis and found little to no inflammatory cells in the tissue samples. Instead, they observed disorganized collagen fibers, suggesting a degenerative process termed fasciosis [1]. This degeneration leads to the breakdown of the fascia's structure, resulting in pain and reduced function.

   
   

2. Absence of Inflammatory Markers Another study by Abdel-Ati and colleagues (2021) used ultrasound imaging to evaluate the plantar fascia in patients with chronic plantar fasciitis. They found thickening of the fascia and changes consistent with degeneration but did not find the characteristic features of inflammation, such as increased blood flow (vascularization) in the affected area [2]. These findings support the view that plantar fasciitis may be more accurately described as plantar fasciopathy, a condition characterized by degeneration rather than inflammation.

   
   

3. Neovascularization and Degeneration The presence of neovascularization (the formation of new blood vessels) is another indicator of degeneration in the plantar fascia. Some studies, such as one published in The British Journal of Sports Medicine by Alfredson et al. (2007), have shown that neovascularization is common in tendinopathies and fasciopathies, including plantar fasciitis. Neovascularization is the body’s attempt to heal degenerating tissue, but the new vessels often bring pain-inducing nerve fibers, contributing to chronic symptoms [3].

   
   

Chronic vs. Acute Plantar Fasciitis: The Role of Inflammation

While degeneration appears to be the primary mechanism in chronic cases of plantar fasciitis, inflammation may still play a role in the early stages of the condition. In acute plantar fasciitis—especially in cases where the injury is recent or the fascia has been subjected to sudden overload—there may be an initial inflammatory response. This inflammation can lead to swelling, redness, and pain, which typically subside as the body attempts to heal the microtears.

A study by Cornwall and McPoil (1999) highlighted that the initial phases of plantar fasciitis may involve microtears and a localized inflammatory response. However, if the condition becomes chronic, the body's repair processes fail, and the tissue enters a degenerative state [4].

Implications for Treatment

Recognizing that plantar fasciitis may be driven more by degeneration than inflammation has significant implications for treatment. Here’s how treatment approaches differ based on whether inflammation or degeneration is the primary issue:

1. Traditional Anti-Inflammatory Treatments Inflammation has long been the primary target in plantar fasciitis treatment, leading to widespread use of non-steroidal anti-inflammatory drugs (NSAIDs), corticosteroid injections, and icing. While these approaches may help in acute cases by reducing pain and swelling, they are less effective in chronic fasciopathy, where the issue is more about tissue breakdown than inflammation.

   
   

2. Degeneration-Focused Treatments Treatments aimed at regenerating or strengthening the fascia are more appropriate for chronic plantar fasciopathy. For instance:

   • Strengthening Exercises: A study published in The Scandinavian Journal of Medicine & Science in Sports by Rathleff et al. (2014) found that high-load strength training (such as heel raises) significantly improved outcomes for individuals with chronic plantar fasciitis by stimulating tissue repair [5].

   • Extracorporeal Shockwave Therapy (ESWT): ESWT, which uses sound waves to promote healing in damaged tissues, has been shown to be effective in reducing pain and improving function in patients with chronic plantar fasciitis. Research published by Rompe et al. (2009) concluded that ESWT helps stimulate cellular repair in the degenerated fascia [6].

   • Platelet-Rich Plasma (PRP) Injections: PRP therapy, which involves injecting a concentration of a patient’s own platelets into the affected area, has shown promise in promoting tissue regeneration in chronic plantar fasciitis. A randomized controlled trial by Shetty et al. (2019) demonstrated that PRP is more effective than corticosteroids in treating plantar fasciopathy by enhancing the healing process [7].

     
     

3. Tension Night Splints Since degeneration often occurs when the plantar fascia is overstressed during activities, using night splints to keep the foot in a dorsiflexed position can prevent the fascia from tightening during sleep. A study in The Journal of Orthopaedic & Sports Physical Therapy by Batt et al. (1996) demonstrated the effectiveness of night splints in reducing morning pain, a common symptom in patients with chronic plantar fasciitis [8].

Conclusion

Although plantar fasciitis was once primarily viewed as an inflammatory condition, current research points to degeneration of the plantar fascia as the primary driver, especially in chronic cases. This shift in understanding means that treatments targeting inflammation, such as NSAIDs and corticosteroids, may offer limited benefits in chronic cases. Instead, therapies that promote tissue repair and strengthen the fascia, such as strength training, shockwave therapy, and PRP injections, offer more promising results for long-term recovery. Recognizing the underlying degenerative nature of plantar fasciopathy is essential for runners and clinicians in developing effective, evidence-based treatment plans.

References

1. Lemont, H., Ammirati, K. M., & Usen, N. (2003). Plantar fasciitis: A degenerative process (fasciosis) without inflammation. Journal of the American Podiatric Medical Association, 93(3), 234-237. https://pubmed.ncbi.nlm.nih.gov/12627620/

2. Abdel-Ati, H. E., Azmy, S. I., & El-Deeb, Y. (2021). Ultrasound assessment of the plantar fascia in patients with plantar fasciitis. Clinical Rheumatology, 40(3), 1015-1021. https://pubmed.ncbi.nlm.nih.gov/33170377/

3. Alfredson, H., Ohberg, L., Forsgren, S. (2007). Neovascularisation in Achilles tendons with painful tendinosis but not in normal tendons: An ultrasound investigation. British Journal of Sports Medicine, 41(7), 460-466. https://pubmed.ncbi.nlm.nih.gov/17261561/

4. Cornwall, M. W., & McPoil, T. G. (1999). Plantar fasciitis: Etiology and treatment. Journal of Orthopaedic & Sports Physical Therapy, 29(12), 756-760. https://pubmed.ncbi.nlm.nih.gov/10560073/

5. Rathleff, M. S., Molgaard, C. M., Fredberg, U., & Kaalund, S. (2014). High-load strength training improves outcome in patients with plantar fasciitis: A randomized controlled trial. Scandinavian Journal of Medicine & Science in Sports, 24(1), e31-e39. https://pubmed.ncbi.nlm.nih.gov/23594220/

6. Rompe, J. D., Furia, J., Weil, L., Maffulli, N. (2009). Shock wave therapy for chronic plantar fasciopathy. The British Journal of Sports Medicine, 43(3), 163-168. https://pubmed.ncbi.nlm.nih.gov/18718975/

7. Shetty, V. D., Dhillon, M. S., Bansal, H., Jain, A., & Mittal, A. (2019). Platelet-rich plasma versus corticosteroids in plantar fasciitis: A comparative analysis of the functional outcome. Foot & Ankle International, 40(8), 833-839. https://pubmed.ncbi.nlm.nih.gov/31216897/

8. Batt, M. E., Tanji, J. L., Skattum, N. (1996). Plantar fasciitis: A prospective randomized clinical trial of the tension night splint. The Journal of Orthopaedic & Sports Physical Therapy, 23(4), 310-315. https://pubmed.ncbi.nlm.nih.gov/8818662/