Plantar Fasciitis

OVERVIEW

Plantar fasciitis is a common cause of heel pain in adults. The pain is usually caused by collagen deterioration at the origin of the plantar fascia at the medial tubercle of the calcaneus. This deterioration is similar to the chronic necrosis of tendonosis, which features loss of collagen continuity, increases in ground substance (matrix of connective tissue) and vascularity, and the presence of fibro-blasts rather than the inflammatory cells commonly seen with the acute inflammation of tendonitis. The cause of the degeneration is repetitive micro-tears of the plantar fascia that overcome the body's capacity to repair itself.

The classic sign of plantar fasciitis is that the worst pain occurs with the first few steps in the morning, but not every patient will have this symptom. Patients often notice pain at the initiation of activity that

Lessens or resolves as they warm up. The pain may also occur with prolonged standing and is sometimes accompanied by stiffness. In more acute cases, the pain will also worsen toward the end of the day.

The plantar fascia is a thickened fibrous aponeurosis that originates from the medial tubercle of the calcaneus and runs forward to form the longitudinal foot arch. The function of the plantar fascia is to provide static support of the longitudinal arch and dynamic shock absorption. Individuals with pes planus (low arches or flat feet) or pes cavus (high arches) are at increased risk for developing plantar fasciitis.

Other anatomic risks include over-pronation (when the feet roll inward too much), discrepancy in leg length, extreme lateral tibial torsion and excessive femoral ante-version. Functional risk factors include rigidity and weakness in the gastrocnemius, soleus, Achilles tendon and intrinsic foot muscles. However, overuse rather than anatomy is the most common cause of plantar fasciitis in athletes. A history of an increase in weight-bearing activities is common, especially those involving running, which causes micro-trauma to the plantar fascia and exceeds the body's capacity to recover. Plantar fasciitis also occurs in elderly adults. In these patients, the problem is usually more bio-mechanical, often related to poor intrinsic muscle strength and poor force attenuation secondary to acquired flat feet and compounded by a decrease in the body's healing ability.

On examination, the patient usually has a point of maximal tenderness at the anteromedial region of the calcaneus. The patient may also have pain along the proximal plantar fascia. The pain may be exacerbated by passive dorsiflexion (foot movement upward produced by the activity of the front part of shin muscles) of the toes when a person stands on the tips of the toes.

Diagnostic testing is rarely indicated for thefirstevaluation and therapy of plantar fasciitis. Plantar fasciitis is often called “heel spurs,” although this terminology is somewhat of a misnomer because 15 to 25 percent of the general population without symptoms have heel spurs and many symptomatic individuals do not. Heel spurs are bony osteophytes that can be visualized on the anterior calcaneus on x-ray. However, diagnostic testing is indicated in cases of atypical plantar fasciitis, in people with heel pain that is suspicious for other causes or in those who are not responding to appropriate treatment.

TREATMENT

In general, plantar fasciitis is a self-limiting condition. Unfortunately, the time until resolution is often 6 to 18 months, which can be frustrating. Rest was cited by 25 percent of patients with plantar fasciitis in one study as the treatment that worked best. Athletes, active adults and persons whose occupations require lots of walking may not be compliant if instructed to stop all activity. Many sports medicine physicians have found that outlining a plan of “relative rest” that substitutes alternative forms of activity for activities that exacerbate the symptoms will increase the chance of compliance with the treatment plan.

It is equally important to correct the problems that place individuals at risk for plantar fasciitis, such as increased amount of weight-bearing activity, increased intensity of activity, hard walking/running surfaces and worn shoes. Early recognition and treatment usually lead to a shorter course of treatment as well as increased probability of success with conservative treatment measures.

ARCH SUPPORTS AND ORTHOTICS

Patients with low arches theoretically have a decreased ability to absorb the forces generated by the impact of foot strike. The three most commonly used mechanical corrections are arch taping, over-the-counter arch supports and custom orthotics. Arch taping and orthotics were found to be significantly better than employment of NSAIDs, cortisone injection or heel cups in one randomized treatment study. Arch taping was cited by 2 percent of patients as the treatment that worked best for plantar fasciitis in another study. A single taping treatment is much less expensive than an over-the-counter arch support or an orthotic.

Taping provides only transient support, with studies showing that as little as 24 minutes of activity can decrease the effectiveness of taping significantly. Arch taping can be used as definitive treatment or as a trial to determine if the expense of arch supports or orthotics is worth the benefit. Taping may be more cost effective for acute onset of plantar fasciitis, and over-the-counter arch supports and orthotics may be more cost-effective for chronic or recurrent cases of plantar fasciitis and for prevention of injuries. In athletes, arches should be re-taped at least for every new game or practice session, whereas an over-the-counter arch support usually lasts a full sports season and a custom orthotic commonly lasts for many seasons.

Over-the-counter arch supports may be useful in patients with acute plantar fasciitis and mild pes planus. The support provided by over-the-counter arch supports is highly variable and depends on the material used to make the support. In general, patients should try to find the most dense material that is soft enough to be comfortable to walk on. Over-the-counter arch supports are especially helpful in the treatment of adolescents whose rapid foot growth may require a new pair of arch supports once or more per season.

Custom orthotics are typically made by taking a plaster cast or an impression of the individual's foot and then constructing an insert specifically designed to control bio-mechanical risk factors such as pes planus, valgus heel alignment and discrepancies in leg length. For patients with plantar fasciitis, the most common prescription is for semi-rigid, three-quarters to full-length orthotics with longitudinal arch support. Two foremost characteristics for successful treatment of plantar fasciitis with orthotics are the need to control over-pronation and metatarsal head motion, especially of the first metatarsal head. In one study, orthotics were cited by 27 percent of patients as the best treatment. The main disadvantage of orthotics is the cost, which may range from $75 to $300 or more and which is commonly not covered by health insurance.

Heel cups are used to decrease the impact on the calcaneus and to theoretically decrease the tension on the plantar fascia by elevating the heel on a soft cushion. Although heel cups have been found to be useful by some physicians and patients, experience shows they are more advantageous in treating patients with fat pad syndrome and heel bruises than patients with plantar fasciitis. In a survey of 400 patients with plantar fasciitis, heel cups were ranked as the least helpful of treatments.


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