Plantar fasciitis. (Fortnightly Review)

Plantar fasciitis is the most common cause of inferior heel pain. Its aetiology is poorly understood by many, which has led to a confusion in terminology.[1] It is said to affect patients between the ages of 8 and 80, but is most common in middle aged women and younger, predominantly male, runners.[2] The role of the doctor in the management of plantar fasciitis is to make an appropriate diagnosis and to allow enough time for the condition to run its course, with the aid of supportive measures. If treatment is begun soon after the onset of symptoms, most patients can be cured within six weeks.[3]

Methods

This article is based largely on our experience and recent concepts that have changed our management of inferior heel pains. Reviews written by experts have been supplemented by selected original articles cited in Medline between 1976 and 1995 and published in high quality journals. We used the following keywords for the Medline search: plantar fasciitis, inferior heel pain, heel spur, calcaneodynia.

Aetiology

The plantar fascia is a strong band of white glistening fibres which has an important function in maintaining the medial longitudinal arch: spontaneous rupture or surgical division of the plantar fascia will lead to a flat foot.[4 5] The plantar fascia arises predominantly from the medial calcaneal tuberosity on the undersurface of the calcaneus, and its main structure fans out to be inserted through several slips into the plantar plates of the metatarso-phalangeal joints, the bases of the proximal phalanges of the toes and the flexor tendon sheaths.

Just after heel strike during the first half of the stance phase of the gait cycle, the tibia turns inward and the foot pronates to allow flattening of the foot. This stretches the plantar fascia. The flattening of the arch allows the foot to accommodate to irregularities in the walking surface and also absorb shock.

If there is a predisposing or aggravating factor (box), the repetitive traction placed on the plantar fascia during walking or running may lead to microtears, which induce a reparative inflammatory response.[6] Biopsy specimens of the inflamed fascia show fibroplastic proliferation and chronic granulomatous tissue.[1 6] A normal plantar fascia has a dorsoplantar thickness of 3 mm; in plantar fasciitis this can be 15mm.[7]

Tightness of the Achilles tendon will predispose to plantar fasciitis because limited dorsiflexion of the foot strains the plantar fascia.[8-11] Furthermore, in plantar fasciitis the foot tends to remain in an equinous position during the night and the fascial tissues contract. In the morning, putting weight on the foot puts the plantar fascia under tension, aggravating the pain. This cycle of heel cord tightness and plantar fasciitis should be interrupted as soon as possible by exercises to stretch the heel cord and by using night splints.

The skin and fat in the heel are specialised for friction and shock absorbency.[12] The skin is thicker on the sole of …