Inferior Heel Pain (Plantar Fasciitis)
S. Brent Brotzman, MD

Clinical Background
Heel pain is best classified by anatomic location (see box following). This section discusses plantar fasciitis (inferior heel pain). Posterior heel pain is discussed in the section on Achilles tendinitis.

Anatomy and Pathomechanics
The plantar fascia is a dense, fibrous connective tissue structure originating from the medial tuberosity of the calcaneus (Fig. 5–18). Of its three portions—medial, lateral, and central bands—the largest is the central portion. The central portion of the fascia originates from the medial process of the calcaneal tuberosity superficial to the origin of the flexor digitorum brevis, quadratus plantae, and abductor hallicus muscle. The fascia extends through the medial longitudinal arch into individual bundles and inserts into each proximal phalanx.

The medial calcaneal nerve supplies sensation to the medial heel. The nerve to the abductor digiti minimi may rarely be compressed by the intrinsic muscles of the foot. Some studies, such as those by Baxter and Thigpen (1984), suggest that nerve entrapment (abductor digiti quinti) does on rare occasions play a role in inferior heel pain (Fig. 5–19).

The plantar fascia is an important static support for the longitudinal arch of the foot. Strain on the longitudinal arch exerts its maximal pull on the plantar fascia, especially its origin on the medial process of the calcaneal tuberosity. The plantar fascia elongates with increased loads to act as a shock absorber, but its ability to elongate is limited (especially with decreasing elasticity common with age). Passive extension of the metatarsophalangeal (MTP) joints pulls the plantar fascia distally and also increases the height of the arch of the foot (Fig. 5–20).

Myth of the Heel Spur
The bony spur at the bottom of the heel does not cause the pain of plantar fasciitis. Rather, this is caused by the inflammation and microtears of the plantar fascia. The spur is actually the origin of the short flexors of the toes. Despite this, the misnomer persists in the lay public and the literature.

Heel spurs have been found in approximately 50% of patients with plantar fasciitis. This exceeds the 15% prevalence of radiographically visualized spurs in normal asymptomatic patients noted by Tanz (1963). However, spur formation is related to progression of age. The symptomatic loss of elasticity of the plantar fascia with the onset of middle age suggests that this subset of patients would be expected to show an increased incidence of spurs noted on radiographs.

Etiology
Inferior (subcalcaneal) pain may well represent a spectrum of pathologic entities including plantar fasciitis, nerve entrapment of the abductor digiti quinti nerve, periostitis, and subcalcaneal bursitis.

Plantar fasciitis is more common in sports that involve running and long-distance walking and is also frequent in dancers, tennis players, basketball players, and nonathletes whose occupations require prolonged weight-bearing. Direct repetitive microtrauma with heel strike to the ligamentous and nerve structures has been implicated, especially in middle-aged, overweight, nonathletic individuals who stand on hard, unyielding surfaces, as well as in long-distance runners.

Some anatomic features seem to make plantar fasciitis more likely. Campbell and Inman (1974) noted that in patients with pes planus, heel pronation increased the tension on the plantar fascia, predisposing the patient to heel pain. Pronation of the subtalar joint everts the calcaneus and lengthens the plantar fascia. A tight gastrocnemius (with increased compensatory pronation) also predisposes patients to plantar fasciitis. Cavus feet with relative rigidity have been noted to place more stress on the loaded plantar fascia. Several studies have shown an association with plantar fasciitis and obesity. However, other researchers have not obtained similar findings.

Bone spurs may be associated with plantar fasciitis, but are not believed to be the cause of it. Many studies show no clear association between spurs and plantar fasciitis. Studies of patients with plantar fasciitis report that 10 to 70% have an associated ipsilateral calcaneal spur; however, most also have a spur on the contralateral asymptomatic foot. Anatomic studies have shown the spur is located at the short flexor origin rather than at the plantar fascia origin, casting further doubt on its role in contributing to heel pain.

Natural History
Although plantar fasciitis can seem quite debilitating during the acute phase, it rarely causes lifelong problems. It is estimated that 90 to 95% of patients who have true plantar fasciitis recover with conservative treatment. However, it may take 6 months to 1 year, and patients often require much encouragement to continue stretching, wearing appropriate and supportive shoes, and avoiding high-impact activities or prolonged standing on hard surfaces. Operative treatment can be very helpful in selected “failed” patients, but the success rate of surgery is only 50 to 85%.

Bilateral Heel Involvement
Bilateral plantar fasciitis symptoms require ruling out systemic disorders such as Reiter’s syndrome, ankylosing spondylitis, gouty arthropathy, and systemic lupus erythematosus. A high index of suspicion for a systemic disorder should accompany bilateral heel pain in a young male aged 15 to 35 years.

Signs and Symptoms
The classic presentation of plantar fasciitis includes a gradual, insidious onset of inferomedial heel pain at the insertion of the plantar fascia (Fig. 5–21). Pain and stiffness are worse with rising in the morning or after prolonged ambulation and may be exacerbated by climbing stairs or doing toe raises. It is rare for patients with plantar fasciitis not to have pain or stiffness with the first few steps in the morning or after a prolonged rest.

Evaluation of Patients with Inferior Heel Pain