The pathomechanics of plantar fasciitis

Abstract

Plantar fasciitis is a musculoskeletal disorder primarily affecting the fascial
enthesis. Although poorly understood, the development of plantar fasciitis is
thought to have a mechanical origin. In particular, pes planus foot types and
lower-limb biomechanics that result in a lowered medial longitudinal arch are
thought to create excessive tensile strain within the fascia, producing microscopic
tears and chronic inflammation. However, contrary to clinical doctrine, histological
evidence does not support this concept, with inflammation rarely observed in
chronic plantar fasciitis. Similarly, scientific support for the role of arch mechanics
in the development of plantar fasciitis is equivocal, despite an abundance of anecdotal evidence indicating a causal link between arch function and heel pain.
This may, in part, reflect the difficulty in measuring arch mechanics in vivo.
However, it may also indicate that tensile failure is not a predominant feature in
the pathomechanics of plantar fasciitis. Alternative mechanisms including
‘stress-shielding’, vascular and metabolic disturbances, the formation of free
radicals, hyperthermia and genetic factors have also been linked to degenerative
change in connective tissues. Further research is needed to ascertain the importance
of such factors in the development of plantar fasciitis.