Plantar fasciitis

What is plantar fasciitis?

Plantar fasciitis continues to be widely used for the clinical syndrome of undersurface heel pain. However, the use of 'itis' denotes an inflammatory disorder. This is a misnomer as the pathology is not the result of excessive inflammation. Pathological changes are degenerative (but partially reversible) in nature, probably due to repetitive trauma¹ .

The plantar fascia is a thick, fibrous band of connective tissue. Its origin is the medial plantar tubercle of the calcaneum. It runs along the sole of the foot like a fan, being attached at its other end to the base of each of the toes. It is a tough, resilient structure that has a number of critical functions during running and walking:

• It stabilises the metatarsal joints during impact with the ground.

• It acts as a shock absorber for the entire leg.

• It forms the longitudinal arch of the foot and helps to lift the arch to prepare it for the 'take-off' phase of the gait cycle.

Plantar fasciitis pathophysiology

Plantar fascia and Achilles tendon

By Ryxi10, via Wikimedia Commons

• The plantar fascia is a sturdy structure but the degree of stress that it takes makes it susceptible to injury. A force equal to almost three times the body's weight passes through the foot with each step. On running, this typically happens about 90 times a minute.

• Plantar fasciitis is thought to be a traction and overuse injury. Damage to the plantar fascia is usually in the form of micro-tears. Plantar fasciitis is a degenerative rather than an inflammatory process² .

• Damage tends to occur near the heel, where stress on the fibres is greatest and where the fascia is the thinnest. The fascia broadens as it extends toward the toes.

• Plantar fasciitis is often associated with calcaneal spurs. These are depositions of calcium where the fascia suffers most damage. Spurs are most commonly on the medial side at the origin of the fascia from the calcaneum. Spurs are the result of the process of plantar fasciitis and not the cause of the pain.

• Plantar fasciitis can present bilaterally.

Epidemiology

Plantar fasciitis is common in runners but can also affect sedentary people³ .

Plantar fasciitis risk factors⁴

• Intrinsic:

  • Pes planus.

  • Pes cavus.

  • Over-pronation.

  • Leg-length discrepancy.

  • Excessive lateral tibial torsion.

  • Excessive femoral anteversion.

  • Being overweight.

  • Gastrocnemius and soleus muscles tightness.

  • Achilles tendon tightness.

  • Gastrocnemius, soleus and intrinsic foot muscles weakness.

  • Ageing of the heel fat pad.

  • Atrophy of the heel fat pad.

  • Plantar fascia stiffness.

• Extrinsic:

  • Overuse.

  • Mechanical stresses and micro-tearing.

  • Incorrect training: a too-fast increase in the distance, intensity, duration or frequency of activities that involve repetitive impact loading of the feet.

  • Inadequate or inappropriate footwear.

History

• The principal complaint is heel/plantar pain. Most often this is 1 or 2 cm distal to the medial calcaneal tuberosity.

• Ask about the onset of the symptoms and any precipitating, aggravating or relieving factors. What brings it on? What makes it worse?
  

  • Plantar fasciitis is often at its most severe during the first few steps after prolonged inactivity, such as sleeping or sitting.

  • Sitting with the foot elevated usually relieves the pain.

  • For those who are on their feet all day, pain is worst at the end of the day.

  • Walking barefoot, on toes, or up stairs can precipitate pain.

• Ask about running or jogging and other sports.

• Ask about footwear and when it was last replaced.

• Ask about previous trauma to the foot.

Examination

• Look at the foot. Note any obvious deformities, skin changes, or congenital conditions. Look for pes planus or pes cavus.

• There is often tightness of the Achilles tendon and ankle dorsiflexion may be limited.

• Palpate the plantar surface over the medial calcaneal tuberosity and along the course of the plantar fascia, pressing quite hard. The reproduction of the pain is the most important physical sign to confirm the diagnosis.

• Pain may be reproduced by asking the patient to stand on their toes or by passive dorsiflexion of the toes.

• Palpate the back of the heel and ankle to exclude Achilles tendonitis.

• Subcalcaneal bursitis produces a tender swelling underneath the calcaneum. It is not aggravated by dorsiflexing the toes. There is usually little or no swelling in plantar fasciitis.

• Referred pain from an S1/S2 lesion should be excluded. Perform the straight leg raising test as for examination of the back. Check the ankle tendon reflex (S1) and calf strength. This is easily performed by asking the patient to walk on toes or stand on one leg and raise the heel off the floor. These tests should be normal.

• Exclude tarsal tunnel syndrome: the posterior tibial nerve passes under the flexor retinaculum which runs between the medial malleolus and the calcaneum. Percuss over the nerve below and posterior to the medial malleolus. This can reproduce pain, numbness and burning on the medial side of the foot, ankle or calf if there is tarsal tunnel syndrome.

• Press together the heads of the 2nd and 3rd metatarsals and then the 3rd and 4th. Reproduction of the pain suggests Morton's neuroma, with entrapment of the common digital nerve between the metatarsal heads.

• A stress fracture of the calcaneum will cause tenderness over the calcaneum rather than anterior to it.

Differential diagnosis

See also the separate Painful Foot and Foot Fractures and Dislocations articles.

• Achilles tendonitis.

• Subcalcaneal bursitis.

• S1 radiculopathy or referred pain.

• Tarsal tunnel syndrome.

• Morton's neuroma.

• Sever's disease (children and adolescents).

• Stress fracture of calcaneum.

Very rarely:

• Fibrosarcoma.

• Metastases.

• Foreign body.

• Paget's disease of bone.

• Osteomyelitis.

• Tuberculosis.

• Gout.

Investigations

The diagnosis is essentially clinical. However, imaging may be required to exclude other possible underlying conditions⁵ .

• Blood tests are not helpful.

• Weighing and measuring the patient may reinforce that the BMI needs attention if obesity is a contributory factor.

• X-ray: should not be performed as a matter of routine but may be indicated if you suspect another diagnosis. A lateral view may show soft tissue calcifications or a calcified spur on the anterior aspect of the calcaneus. X-ray may also help to exclude stress fracture, although stress fractures may not always be evident.

• Ultrasound: this may show a thicker heel aponeurosis in plantar fasciitis⁶ .

• Bone scans and MRI: these have also been used in diagnosis.

Plantar fasciitis treatment and management

There is no one treatment with very strong evidence of efficacy; however, there are several treatment options with moderate levels of evidence, including stretching, orthotics, shock-wave therapy and injections. Plantar fasciitis treatments should be offered in sequence, depending on the individual patient's circumstances and likelihood of response¹ .

General advice

• Resting of the foot as much as possible.

• Loss of weight if obese.

• Correction of pes planus if present.

• Advice to run on a softer surface.

• A laced sports shoe gives good support. Update shoes regularly.

• If the patient is an athlete, discuss training schedules. Cardiovascular fitness may be built by a shift, even temporarily, to swimming, cycling, a step machine in a gym or other low-impact exercise.

• Non-steroidal anti-inflammatory drugs and ice may be useful.

• Patients should be counselled that with any conservative management plan they should not expect to note a significant improvement in symptoms before 6-8 weeks² .

Physiotherapy and stretching exercises

• Stretching exercises are often advised for the plantar fascia, calf muscles and the Achilles tendon. Again, hard evidence for their use is lacking⁷ . However, benefit has been shown in some studies⁸ . The patient may be taught to do these exercises independently.

• Deep massage of the sole of the foot also stretches the plantar fascia.

• A physiotherapist may also recommend ultrasound, laser treatment, or iontophoresis with dexamethasone to assist pain relief and reduce inflammation. Again, evidence for these treatments is limited.

Orthotics, splinting and casting

• A heel and arch support may help. However, a review showed that even though there is some evidence to support the use of foot orthoses in the prevention of lower-limb overuse injuries, there is limited evidence for their use in the treatment⁹ . Another study showed that they had short-term but not long-term treatment benefits¹⁰ . A Cochrane review suggested that there was silver level evidence for their use¹¹ . Various pads and shoe inserts can be bought to cushion and raise the heel and give good arch support. Inserts should be worn in both shoes, even if pain is only in one foot.

• Night splints to keep the ankle dorsiflexed and the toes extended can help to stretch the plantar fascia and may induce faster healing.

Corticosteroid injection

The evidence for steroid injection shows that it may provide some short-term benefit for plantar fasciitis but the evidence for its effectiveness in the long term is lacking¹² . Counsel the patient accordingly.

The technique

• A posterior tibial nerve block before injection has been suggested to reduce pain of the injection.

• Ultrasound guidance has been used to facilitate accurate injection^{13 14} .

• Plantar fascia rupture may also be a complication of steroid injection.

• Use a maximum of three injections in six months.

Other modalities

• Extracorporeal shock-wave therapy: a meta-analysis has shown this to be a safe and effective treatment which may be preferable to steroid injection¹⁵ . However, the National Institute for Health and Care Excellence (NICE) states that, although the evidence on extracorporeal shock-wave therapy for refractory plantar fasciitis raises no major safety concerns, current evidence on its efficacy is inconsistent¹⁶ .

• Botulinum toxin A injections: may produce some benefit in the short term¹⁷ .

• Autologous blood injection: the idea is that growth factors promote healing of the plantar fascia by stimulating fibroblast activity and vascular growth. There is currently a lack of long-term evidence for this technique¹⁸ . In one study it was shown to be effective in lowering pain and tenderness in chronic plantar fasciitis but corticosteroid injections were found to be superior in terms of speed and probably extent of improvement¹⁹ .

• Radiotherapy has been shown to provide effective pain relief²⁰ .

• Surgery: endoscopic fasciotomy may be required in patients who continue to have pain that limits activity and function despite exhausting non-operative treatment options³ .

Plantar fasciitis prognosis

• Pain may be long-standing and can last for some years. However, plantar fasciitis generally resolves over time and with minimally invasive management¹ .

• 80% show spontaneous response within 12 months.

Plantar fasciitis prevention

• Regularly changing footwear used for running and walking.

• Wearing shoes with good cushioning in the heels and good arch support.

• Losing weight if overweight.

• Avoiding exercising on a hard surface.

• Regular stretching exercises for the plantar fascia and Achilles tendon.