The plantar fascia is a thick layer of connective tissue that originates from the heel and fans out to the underside of each toe. It provides support to the arch of the foot and serves as a shock absorber during activities like running and walking that require extension of the toes. As the toes extend, the plantar fascia tightens and elevates the arch of the foot.
When a person suffers from plantar fasciitis, the bottom of the foot gets irritated and swells.
Obesity, sudden weight gain, prolonged standing or weight-bearing and overtraining in runners are risk factors for plantar fasciitis. All these activities place increased, repetitive tensile forces on the plantar fascia.
Other risk factors include flat feet and reduced dorsiflexion (upward flexion of ankle) because of improper distribution of load on the fascia.
Heel spurs are found in 50 percent of those with plantar fasciitis, although the mechanism with which they produce fascial damage is unclear. Systemic diseases such as diabetes mellitus and rheumatic disease have also been linked to plantar fasciitis as they lead to changes in the muscular and bony structure of the feet.
Plantar fasciitis is a degenerative condition that results from repetitive stress that causes micro-tears in the fascia. If these tears occur frequently, the body loses its ability to heal itself, so a chronic state of inflammation ensues. The hallmark symptom of plantar fasciitis is heel or arch pain in the sole of the foot. This pain is often worse at the beginning of the aggravating activity and lessens as the foot warms up. With severe plantar fasciitis, pain may be also be worse at the end of the day.
Diagnosis of plantar fasciitis is made based on the patient's symptoms and a physical examination by a clinician. Tenderness experienced by the patient may be reproduced by the clinician with flexion of the toes and ankle as well as upward and palpating the length of the fascia.
Plain X-rays may be taken to rule out the presence of heel spurs and other causes of inferior heel pain — like a stress fracture or a bone malformation. Magnetic Resonance Imaging should be taken to rule out soft tissue disease in cases of intractable plantar fasciitis that doesn't get better after conservative management.
Plantar fasciitis is a condition that can take six – 18 months to resolve. Treatment begins with conservative management such as weight reduction and avoiding activities that irritate the foot. Mechanical support for the foot can be achieved through arch supports, heel cups, night splints and orthotics that can relieve pressure off the plantar fascia. Stretching and strengthening are also important aspects of the treatment. Stretching the soleus and gastrocneumius muscles and the plantar fascia can be accomplished with the stair and ball-rolling stretches along with cross-friction massage. Strengthening exercises improve the muscles of the foot.
Ice and anti-inflammatory medications can help manage foot pain. Longer-lasting anti-inflammatory medication such as corticosteroid injections may be used for chronic heel pain. Multiple injections, however, can increase the risk of fascial weakness or rupturing, lead to fat pad atrophy and infection of the heel bone. Although these side effects can be prevented, steroid injections are reserved for persistent cases.
Reviewed by health care specialists at UCSF Medical Center.