Plantar Fasciitis

The plantar fascia is a thick, fibrous band of connective tissue which originates at the calcaneum and runs along the sole of the foot like a fan, to be attached 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 stabilizes the metatarsal joints during impact with the ground. It acts as a shock absorber for the entire leg. It helps to lift the longitudinal arch of the foot to prepare it for the 'take-off' phase of the gait cycle.
The fascia is a sturdy structure but the degree of stress that it takes makes it susceptibility to injury. The fascia takes a force equal to almost 3 times body weight passing through the foot with each step. On running, this typically happens about 90 times a minute. Damage tends to occur near the heel, where stress on the fibres is greatest, and where the fascia is the thinnest. It broadens as it extends toward the toes.
There is often an association with calcaneal spurs. These are depositions of calcium where the fascia suffers most damage. This damage is usually in the form of micro-tears. Pain is mostly at the base of the heel. Spurs are most commonly on the medial side at the origin of the fascia from the calcaneum. Spurs are the result of the process and not the cause of the pain.

• It is a common problem.
• Women are affected twice as often as men.
• About 5 to 10% of running injuries are fasciitis.

Risk factors

• Most sports involve some degree of running and jumping so that basketball players, tennis players, step-aerobics participants, and dancers are all susceptible to plantar problems.
• Non-athletic people who spend much of each day on their feet are at risk.
• It may appear in someone who suddenly becomes active after a long period of indolence.
• Running on hard ground increases risk as does an increase in hill training.
• Worn out trainers increase risk as they lose their shock absorption properties.
• Obesity increases risk. This is unsurprising as the stress through the fascia is dependent upon body weight.
• Other mechanical risk factors include flat feet, high arch and pregnancy. The last is associated with a temporary and physiological gain in weight whilst hormones cause relaxation of ligaments, predisposing to flat feet.

• The principle complaint is 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?
  • It 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.
• Ask about running or jogging. Ask about sport.
• Ask about footwear and when it was last replaced.
• Ask about previous trauma to the foot, perhaps from falls, road traffic accidents, or injuries at work.

• Look at the foot. Note any obvious deformities, skin changes, or congenital conditions. Flat feet produce callus other than on the heel and under the 1st and 5th metatarsal heads.
• There is often tightness of the Achilles tendon.
• 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.
• Palpate the back of the heel and ankle to exclude retrocalcaneal bursitis or Achilles tendonitis.
• Referred pain, as in radiculopathy at S1 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.
• The tarsal tunnel syndrome can be tested by percussing over the tarsal tunnel behind the medial malleolus. There is no pain with plantar fasciitis.
• 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.

The important differential diagnoses have been covered in the physical examination by procedures to exclude them.

• Retrocalcaneal bursitis or Achilles tendonitis
• S1 radiculopathy or referred pain
• Tarsal tunnel syndrome
• Morton's metatarsalgia
• Stress fracture of calcaneum

• No blood tests are helpful.
• Weighing and measuring the patient may reinforce that the BMI needs attention and obesity is a contributory factor.
• X-ray should not be performed as a matter of routine but may be indicated if there has been no response to a month or two of therapy and injection is considered. A lateral view shows a calcified spur on the anteroinferior aspect of the calcaneus. It is the result, not the cause of the condition. X-ray may also help to exclude stress fracture although they can also be missed.

There may be an association with seronegative arthropathies as well as flat feet and high arches.

Injection of a calcaneal spur is not the first approach but is fairly low in the order of management.

General Advice

This means identification of risk factors and advice to avoid them.

• Loss of weight if obese.
• Correction of pes planus if present.
• Advice to run on a softer surface or to replace worn out trainers.
• Better footwear if a long day on the feet is an issue. A raised heel and arch support may help.
• If 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 some such low impact exercise.

Physical Therapy

Stretching exercises are often advised for both the plantar fascia and the Achilles tendon. Forced dorsiflexion of the ankle and toes stretches both. Deep massage of the sole of the foot stretches the plantar fascia.The patient may do this or another person.
Ice may be applied after exercise. A physiotherapist may recommend ultrasound, phonophoresis, or iontophoresis, to assist pain relief and reduction of inflammation.
An arch support for flat feet will correct abnormal forces.
Exercises may be orientated to stretching or to strengthening. The Internet and further reading references by Anderson and Reynolds is recommended for containing explicit instructions for exercises to help the condition.

Other Modalities

• The prescription of NSAIDs may be useful.
• A heel pad made of silicone, rubber, gel or felt may be useful. They can be purchased at many pharmacies.
• There is a place for steroid injection if other treatments have failed.
• A meta-analysis of shockwave therapy has shown it to be a safe and effective treatment that may be preferable to steroid injection.¹ However, NICE expressed concern about the possibility of rupture of the Achilles tendon.² A Cochrane review.³ was firmly of the opinion that it is useless for tennis elbow.
• Botulinum toxin A injections also seem to produce benefit in the short term.⁴

Corticosteroid Injection

It is usual to delay steroid injection until around 6 weeks of physical treatment have proved ineffective. The technique involves pushing a needle through some very tough skin and it is so painful that it should not be undertaken lightly.

A mixture of steroid and local anaesthetic is usually used. A volume of around 5ml is usually injected using a 21-gauge (green hub) needle as a smaller one may fail to penetrate the tough skin.
• Palpate the most anterior aspect of the medial plantar calcaneal tubercle and insert the needle at this site.
• Advance the needle until it reaches the most anterior (distal) aspect of the plantar medial calcaneal tuberosity.
• When the proximal (anterior) edge of the heel spur has been identified, advance the needle immediately anterior to this spot.
• Avoid injecting into the superficial layers of the subcutaneous tissue, as steroid injection can cause fat necrosis and atrophy, resulting in a loss in the shock absorption of the plantar heel.

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.⁵

Inaccurate placement of steroid injection can cause fat pad necrosis and reduce shock absorption.

Most patients respond to physical treatment but it often needs to be energetic.

• Runners should have appropriate shoes
• A change in training schedules may be required at an early stage
• Suitable work shoes should be worn.

The level of evidence on which to base advice is generally poor. RCTs of various modalities have been few or absent and often underpowered, especially to detect adverse effects. A Cochrane review⁶ concluded:

• There is limited evidence upon which to base clinical practice.
• Steroid injections are a popular method of treatment but only seem to be useful in the short term and only to a small degree.
• Other frequently employed treatments have not been established in RCTs.
• Treatments bring marginal gains over no treatment and control therapies such as stretching exercises.
• Orthoses should be cautiously prescribed for patients who stand for long periods.
• There is limited evidence that stretching exercises and heel pads are associated with better outcomes than custom made orthoses in people who stand for more than eight hours per day.
• Well designed and conducted randomised trials are required.

Clinical Evidence⁷ was also very negative about benefits and levels of evidence. The author of Clinical Evidence was also the first author of the Cochrane review.