The plantar fascia is a thick layer of connective tissue that originates from the heel (calcaneus) 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 that require extension of the toes (e.g., running, walking). As the toes extend, the plantar fascia tightens and elevates the arch of the foot.
Plantar fasciitis is a degenerative condition that results from repetitive stress that cause micro-tears in the fascia. If these tears occur frequently enough to overcome the body’s ability to heal itself, 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.
Obesity, sudden weight gain, prolonged standing / weight-bearing, and overtraining in runners are risk factors for plantar fasciitis as they all 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% 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 implicated as they lead to changes in the muscular and bony structure of the feet.
Diagnosis of plantar fasciitis is made on the basis of the symptoms described above and physical examination by a clinician. Local tenderness experienced by the patient is best reproduced by the clinician with flexion of the toes and ankle upward and palpating the length of the fascia.
Plain x-rays should be undertaken to rule out the presence of heel spurs and other causes of inferior heel pain (e.g., calcaneal stress fracture, bone malformations). MRIs (magnetic resonance imaging) should be undertaken to rule out soft tissue disease in cases of intractable plantar fasciitis after conservative management.
Plantar fasciitis is a self-limited condition but can take 6-18 months to resolve. Treatment begins with conservative management. This includes weight reduction and avoidance of aggravating activities. Mechanical support of the foot through the arch support, heel cups, night splints and orthotics optimally position the foot to relieve pressure off the plantar fascia. Stretching and strengthening are important aspects of the treatment. Stretching of the soleus and gastrocneumius muscles and the plantar fascia can be accomplished with the stair stretches, ball-rolling stretches, and cross-friction massage (shown below). Strengthening exercises improve the intrinsic muscles of the foot.
Acute management of pain may be accomplished with ice and anti-inflammatory medications (e.g., ibuprofen). Longer-lasting anti-inflammatory medication may be used in the form of corticosteroid injections for chronic heel pain. However, multiple injections include the risk of fascial weakness and rupture, fat pad atrophy, infection of the heel bone. Thus, although these side effects can be prevented with good technique and avoidance of impact activities, steroid injections are reserved forpersistent cases.
In the most severe cases, surgery may be undertaken to incise and release the pressure off the fascia. Newer forms of therapy, such as sound wave therapy (extracorporeal shock-wave therapy) and botulinum toxin, may be more widely available in the future but currently have limited evidence of efficacy.