Plantar Fasciitis

 

Introduction:

Plantar fasciitis is an extremely common and often disabling condition of the foot. It occurs in around 10% of the population, in all ages, but is more common into the 40’s and 50’s, with a female preponderance

 

Etiology:

The plantar fascia is a robust ligament that makes up the arch of the foot. Plantar fasciitis is a degenerative condition. As the plantar fascia wears it becomes more prone to injury, either from overuse, causing micro tears, or from a single traumatic mechanism. As with most tendinopathy the natural history is favorable for improvement, but the time frames may be prolonged, not uncommonly running into 12-18 months. Statistically 70% of patients with plantar fasciitis will be better in 6 months and 90% in 12 months, irrespective of treatment.

 

Diagnosis:

Historically plantar fasciitis presents as well localized pain on the medial aspect of the anterior calcaneus. It is classically worse first thing in the morning, walking after sitting and with prolonged time on feet. It may come about after a change in exercise volume, or often simply spending more time on feet.

Clinically the patient will have direct tenderness over the medial calcaneal facet. There may be associated foot hyperpronation, calf inflexibility or stiffness in the sub-talar joint.

 

Investigation

The diagnosis of plantar fasciitis is considered to be clinical. Plain X-rays commonly show a plantar spur. Whilst there is an association between the spur and plantar fasciitis, it is not directly causal. X-ray is important to rule out other conditions such as a calcaneal stress fracture, sub-talar arthritis or a tumor. Ultrasound is not mandatory, and generally shows a thickening or swelling of the plantar fascia. Likewise, MRI can be helpful in confirming plantar fascia degeneration and swelling and excluding other conditions in recalcitrant cases such as sub-talar joint synovitis.

In chronic or bilateral plantar fasciitis in the younger patient inflammatory enthesopathy should be considered. A blood screen may be required including an ESR, CRP, ANA and a HLA-B27.

 

Treatment:

The treatment of plantar fasciitis is symptomatic and expectant. Initial symptom relief may be achieved with simply getting off the foot and resting from offending activities such as running or exercise walking. Simple analgesics or anti-inflammatories may be helpful for pain relief. Heel cushions or pads such as Tulis heel cups may relieve pain. Calf stretching is essential and up to 80% of patients will improve with this measure alone. It needs to be a prolonged stretch, dropping the heels off a step for 2-3 minutes twice daily. Likewise icing and massage may be combined by rolling the foot over a frozen bottle 1-2 times during the day. Footwear should be appropriate and weight loss is ideal.

If these measures are unhelpful then further treatment may include wearing a splint at night, such as a Strassburg sock, to prevent calf tightening overnight. Orthotic prescription has been proven to help plantar fasciitis by improving hyper-pronation. Physiotherapy can also help by improving calf and plantar fascia flexibility and sub-talar mobility. Intrinsic muscle strengthening is also beneficial. If the pain is significant then trial of a walking boot for 6 weeks may be appropriate.

 

Fig 1. Strassburg Sock

If these measures are unhelpful, or the patient has severe pain, it may be reasonable to consider injection therapy. Historically cortisone has been shown to be helpful for pain relief for up to 6 weeks in around 70% of patients. Serial injections may be reasonable to reduce pain in more severe cases. More recently PRPP injections (an injection of a platelet concentrate of the patients own blood around the insertion point to stimulate a healing response) have been shown to have benefit in chronic plantar fasciitis. Extra-corporeal shock wave therapy (ESWT) may also have a role to play in the treatment of chronic plantar fasciitis. Surgical release of the plantar fascia is seldom indicated, but is an alternative if all other measures have failed.

 

Key Points

• Plantar fasciitis is a common degenerative ligament condition of the foot
• It presents with localized heel pain, classically worse first thing in the morning and with prolonged time on feet
• The prognosis is favorable in most patients, but the times frames for resolution may be prolonged
• Simple treatments such as calf stretching, ice massage and heel cushions are helpful in most cases

Resistant plantar fasciitis may require night splinting, boot immobilization or consideration of injection therapy