Heel Spurs? Where do these things come from?

Many people claim heel spurs to be an abnormal finding. However, research dating from the early 60’s to late 90’s have reported anywhere from 11-16% of the general population to have some type of heel spur.

It’s debatable if heel spurs are strongly correlated to older age, gender and osteoarthritis. However, the debate linking heel spurs and pain has progressed to treatment involving shock wave therapy, surgical incision and even radiation therapy


The Debate: Traditionally the pathophysiology of spurs forming was based on what was called the longitudinal traction hypothesis.
         

Why the Traction Theory?: It was thought; the plantar fascia’s insertion creates traction and thus develops inflammation. Now from this inflammation reactive ossification is formed in the plantar fascia’s enthesis leading to the formation of a spur. Studies started to support this theory with the link of flatfooted people and heel pain. It was believed having a lower longitudinal arch created tension and thus the pain was created.   

Evidence for a Non Traction Theory: 1) Heel spurs have been found to be located deep to the plantar fascia rather than at its insertion point. Heel spurs have also been shown to be closely related to other muscle insertions such as the quadrates plantae, flexor digitorum brevis and abductor hallucis. Some heel spurs are not even correlated to muscle insertions but rather found within fibrocartilage and loose connective tissue.

2) Excised plantar fascia doesn’t show histological evidence of inflammation

3) Bony trabeculae have not been found to align in a direction of traction

4) Excised spurs have been shown to reform after a surgical released plantar fascia.                                                                                                                                                                                                                The alternative theory:Another theory can be one of vertical compression hypothesis (Kumai & Benjamin) which purposes a heel spur is due to compressive forces rather than traction. They suggest heel spurs are fibrocartiligenous overgrowths that occur in response to a microscopic stress fracture. These overgrowths are simply the calcaneus’s way of protecting itself from micro cracks.  

 

Support: Heel spurs are more common in subjects which are overweight and have decreased elasticity in their fat pads. Furthermore, histological studies on cadavers have shown bony trabeculae of spurs to be vertically aligned as if compensating for a compressive force.     

 

The research: A recent study involving 216 subjects found further support for a compressive hypothesis. Subjects were over the age of 62 and had either a heel or achilles spur. The spurs were found to be correlated to obesity (BMI), osteoarthritis and pain. However, there was no significant correlation found with foot posture (x-ray measures). Obese and OA findings indicate compressive forces may be involved. The lack of foot posture being correlated also strengthens the argument. If traction was the main culprit all those with flatfeet would have been strongly linked.                                                                                                                                                                                                                                                     To rebuttal those studies which also link obesity and a low longitudinal arch this factor may be argued to be more so related to the biomechanical properties of pronation.                                                                                                                                                                                                                                   

  The findings of pain don’t really indicate either theory. This again strengthens the whole controversy of what actually causes the pain from a heel spur. Is it the spur itself or the soft tissue around it?                                                                                                                                                                                                             

What about the anatomy? Studies have found almost any variation of where a heel spur can lie in the foot anatomically. However, the more recent research supports a theory of compression where heel spurs are not always found within the plantar enthesis.  The most recent study inspected 37 spurs in 20 cadavers. Multiple variations were found using different forms of imaging. This study purposed that the cause of a spur isn’t necessarily traction and much more complex then probably previously thought. They found spurs to form when surrounded by loose connective tissue. Furthermore, those spurs aligned with the plantar fascia’s enthesis didn’t always have a bony trabeculae pattern which replicated a cause of traction forces. Some heel spurs had a basket weave like patterns.                                                                                                                              This pattern supports wolfs law regarding bony articulation taking on the form of dynamic stress. In summary, we now have strong implication to believe heel spurs are more so due to compressive forces. The clinical significance of these findings is significant. One has to find the cause of a diagnosis before aiming to treat it. If the traction hypothesis is correct one may aim to limit such forces by releasing the plantar fascia with stretching, aggressive soft tissue therapy of surgical incision. However, if due to compressive forces one may aim to treat the injury like a stress fracture focusing on relative rest and an orthotic designed to decrease forces. Dr. Wayne Button, BSc, D.C

Li, J., & Muehleman, C. (2007). Anatomic relationship of heel spur to surrounding soft tissues: Greater variability than previously reported Clinical Anatomy, 20 (8), 950-955 DOI: 10.1002/ca.20548 Li, J., & Muehleman, C. (2007). Anatomic relationship of heel spur to surrounding soft tissues: Greater variability than previously reported Clinical Anatomy, 20 (8), 950-955 DOI: 10.1002/ca.20548 Menz, H., Zammit, G., Landorf, K., & Munteanu, S. (2008). Plantar calcaneal spurs in older people: longitudinal traction or vertical compression? Journal of Foot and Ankle Research, 1 (1) DOI: 10.1186/1757-1146-1-7