Plantar Fasciitis: Why the Heel Hurts and How to Resolve It

What Is Plantar Fasciitis?

Plantar fasciitis is the most common cause of heel pain, resulting from repetitive overload of the plantar fascia — a thick band of connective tissue that connects the heel bone (calcaneus) to the toes, supporting the longitudinal arch of the foot.

Although the term "fasciitis" suggests inflammation, histopathologic studies show that the chronic condition predominantly involves collagen degeneration (fasciosis) rather than active inflammation. Inflammatory processes occur mainly in the early phases.

The most characteristic symptom is heel pain with the first steps in the morning or after prolonged periods of rest. This pain tends to improve with movement but may return after prolonged standing.

Epidemiology

Plantar fasciitis accounts for approximately 80% of heel pain cases. An estimated 1 in 10 people will develop the condition during their lifetime. It is particularly common in runners and professionals who spend long hours standing.

Well-established risk factors include elevated BMI (above 30 kg/m²), flat or excessively cavus foot, Achilles tendon shortening, work requiring more than 8 hours of standing, inadequate footwear, and sudden increases in training volume in runners.

Pathophysiology

The plantar fascia is a structure of dense connective tissue, composed mainly of type I collagen fibers. It originates from the medial process of the calcaneal tuberosity and inserts into the base of the proximal phalanges of the toes, forming five digital bands.

Windlass Mechanism

The plantar fascia functions as a "winch" (windlass mechanism): during the propulsion phase of gait, toe dorsiflexion tensions the fascia, raising the longitudinal arch and turning the foot into a rigid propulsion lever. This mechanism is essential for normal gait biomechanics.

Repetitive overload of this mechanism causes microtears at the insertion of the fascia on the calcaneus. In the chronic phase, collagen degeneration occurs with disorganization of fibers, neovascularization, and angiofibroblastic hyperplasia — a process similar to tendinopathy.

Why Does It Hurt in the Morning?

During sleep, the foot rests in slight plantar flexion. In this position, the fascia shortens and microtears begin healing. On the first morning step, body weight abruptly tensions these healing areas, causing new microtears and acute pain.

After a few minutes of walking, the fascia gradually elongates and pain subsides. However, after prolonged standing or excessive activity, accumulated mechanical stress brings the pain back.

Symptoms

The clinical picture of plantar fasciitis is quite characteristic, making diagnosis straightforward in most cases.

Diagnosis

The diagnosis of plantar fasciitis is essentially clinical, based on a typical history and physical examination. Imaging studies are necessary only to rule out other causes of heel pain or in atypical cases.

On physical examination, palpation of the medial calcaneal tuberosity (the fascia's insertion point) reproduces the pain. The passive toe dorsiflexion with weight-bearing test (windlass test) also provokes symptoms.

Achilles Tendinopathy

Achilles tendinopathy is the second most common cause of heel pain and is easily confused with plantar fasciitis when the tendon insertion is involved (insertional tendinopathy). Anatomical location is the main distinguishing feature: in plantar fasciitis, pain is on the plantar surface of the calcaneus, whereas in Achilles tendinopathy pain is on the posterior surface — at the tendon insertion or in the tendon body, 2-6 cm above the insertion (non-insertional form).

Tendon ultrasound confirms the diagnosis by showing thickening, hypoechogenicity, and possible neovascularization on Doppler. The Thompson test (calf compression without plantar flexion) assesses tendon integrity. Treatment of Achilles tendinopathy relies on eccentric exercises of the gastrocnemius-soleus complex, with careful load progression to avoid rupture.

Tarsal Tunnel Syndrome

Tarsal tunnel syndrome results from compression of the posterior tibial nerve in the tunnel formed by the ankle's medial flexor retinaculum. It manifests with burning, tingling, and numbness on the sole of the foot and toes, and may be confused with the plantar pain of fasciitis. The clinical distinction lies in the neuropathic character of the pain (burning, paresthesias) versus the mechanical character of fasciitis (pain with weight-bearing and the first step).

A positive Tinel sign — paresthesias reproduced when percussing the posterior tibial nerve at the medial ankle — has good diagnostic specificity. Electroneuromyography quantifies the loss of nerve conduction and confirms the diagnosis, and is essential for treatment planning. In cases refractory to conservative treatment, surgical decompression of the tarsal tunnel may be indicated.

Calcaneal Stress Fracture

A calcaneal stress fracture occurs when repetitive microtrauma exceeds the bone's remodeling capacity, and is especially common in runners with sudden increases in training volume, military personnel during basic training, and women with osteoporosis. Pain is diffuse throughout the heel (not localized at the medial plantar insertion as in fasciitis), progressively worsens with weight-bearing, and can be reproduced by the lateral calcaneal compression test — a highly suggestive finding.

Plain radiography may be normal in the first 2-3 weeks. Magnetic resonance imaging is the test of choice, detecting bone edema before the fracture line is visible. Bone scintigraphy is more accessible and highly sensitive, although less specific. Treatment requires offloading for 6-8 weeks, orthotics, and bone mineral density assessment if underlying osteoporosis is suspected.

Fat Pad Atrophy

The plantar fat pad is a specialized cushion of adipose tissue that absorbs impact during gait. With aging, chronic systemic corticosteroid use, or repeated heel corticosteroid injections, this tissue can atrophy, causing diffuse plantar pain when walking. Unlike plantar fasciitis, the pain is neither characteristically a morning pain nor localized at the fascial insertion — it is generalized and worsens throughout the day with weight-bearing.

On physical examination, the bony structures of the calcaneus are prominent through the skin, with visible and palpable reduction of the fat pad. Ultrasound quantifies pad thickness (normal: 10-17 mm). Treatment is conservative, with silicone cushioning insoles and footwear with a thick midsole. This is why repeated corticosteroid injections in plantar fasciitis are discouraged: they can worsen fat pad atrophy and turn a treatable condition into a chronic one.

Morton Neuroma

Morton neuroma is a perineural fibrosis of the plantar interdigital nerve, most often between the 3rd and 4th toes, caused by repetitive compression. It manifests as burning or shock-like pain in the forefoot (between the toes), unlike plantar fasciitis, whose pain predominates in the rearfoot. Paresthesias in the toes adjacent to the affected nerve are typical and guide the diagnosis.

Mulder's sign — pain and a palpable "click" reproduced by laterally compressing the forefoot — has 60-70% diagnostic sensitivity. Ultrasound identifies the lesion in 95% of cases as a hypoechoic nodule between the metatarsal heads. Treatment includes insoles with a metatarsal bar, footwear with a wide toe box, and, in refractory cases, corticosteroid or sclerosing injection, or surgical excision.

Treatments

Conservative treatment is effective in more than 90% of cases, although complete recovery may take several months. The approach should be multimodal, combining different strategies simultaneously.

Essential Stretches

Specific plantar fascia stretching is the exercise with the most evidence. It is performed by crossing the affected leg over the other and pulling the toes into dorsiflexion until the stretch is felt on the sole of the foot. Hold for 30 seconds, repeat 10 times, 3 times per day.

Stretching of the gastrocnemius-soleus complex is equally important. Limited ankle dorsiflexion increases the load on the fascia during gait. Stretches with the knee extended (gastrocnemius) and flexed (soleus) should be performed daily.

Acupuncture as Treatment

Acupuncture has been used as a complementary treatment for plantar fasciitis, with growing evidence of its efficacy. A systematic review published in the journal Acupuncture in Medicine concluded that acupuncture provides significant pain relief in the short and medium term.

Proposed mechanisms include local analgesia through adenosine and endogenous opioid release, modulation of neurogenic inflammation at the fascial insertion, and improved microcirculation, which favors tissue healing.

Dry needling of trigger points in the gastrocnemius and soleus muscles, frequently associated with plantar fasciitis, may complement treatment by reducing muscle tension that overloads the fascia.

Prognosis

Plantar fasciitis is self-limiting in most cases, but recovery can be prolonged. Patience and consistent adherence to treatment are essential.

Myths and Facts

When to Seek Medical Help