Plantar Fasciitis

The plantar fascia is a thickened fibrous aponeurosis that originates from the medial tubercle of the calcaneus, runs forward to insert into the deep, short transverse ligaments of the metatarsal heads, dividing into 5 digital bands at the metatarsophalangeal joints[6] and continuing forward to form the fibrous flexor sheathes on the plantar aspect of the toes. Small plantar nerves are invested in and around the plantar fascia, acting to register and mediate pain.

The plantar fascia is made up of 3 distinct parts: the medial, central, and lateral bands. The central plantar fascia is the thickest and strongest section, and this segment is also the most likely to be involved with plantar fasciitis. In normal circumstances, the plantar fascia acts like a windlass mechanism to provide tension and support through the arch.[7] It functions as a tension bridge in the foot, providing both static support and dynamic shock absorption.[8]

Biomechanical dysfunction of the foot is the most common etiology of plantar fasciitis; however, infectious, neoplastic, arthritic, neurologic, traumatic, and other systemic conditions can prove causative. The pathology is traditionally believed to be secondary to the development of microtrauma (microtears), with resulting damage at the calcaneal-fascial interface secondary to repetitive stressing of the arch with weight bearing.[9, 10, 11]

Excessive stretching of the plantar fascia can result in microtrauma of this structure either along its course or where it inserts onto the medial calcaneal tuberosity. This microtrauma, if repetitive, can result in chronic degeneration of the plantar fascia fibers. The loading of the degenerative and healing tissue at the plantar fascia may cause significant plantar pain, particularly with the first few steps after sleep or other periods of inactivity.

The term fasciitis may, in fact, be something of a misnomer, because the disease is actually a degenerative process that occurs with or without inflammatory changes, which may include fibroblastic proliferation. This has been proven from biopsies of fascia from people undergoing surgery for plantar fascia release.

Studies have introduced the etiologic concept of fasciosis as the inciting pathology. Fasciosis, like tendinosis, is defined as a chronic degenerative condition that is characterized histologically by fibroblastic hypertrophy, absence of inflammatory cells, disorganized collagen, and chaotic vascular hyperplasia with zones of avascularity.[12, 13, 14]

These changes suggest a noninflammatory condition and dysfunctional vasculature, which may be seen on ultrasound.[15] With reduced vascularity and a compromise in nutritional blood flow through the impaired fascia, it becomes difficult for cells to synthesize the extracellular matrix necessary for repairing and remodeling.[16]

Biomechanics of running

During running, the vertical forces in the foot at foot strike may reach 2-3 times an individual’s body weight.[17] The plantar fascia and longitudinal arch are also part of the foot’s shock absorption mechanism. During the heel-off phase of gait, tension increases on the plantar fascia, which acts as a storage of potential energy. During toe-off, the plantar fascia passively contracts, converting the potential energy into kinetic energy and imparting greater foot acceleration

The cause of plantar fasciitis is often unclear and may be multifactorial. Because of the high incidence in runners, it is best postulated to be caused by repetitive microtrauma. Possible risk factors include obesity, occupations requiring prolonged standing and weight-bearing, and heel spurs.[18] Other risk factors may be broadly classified as either extrinsic (training errors and equipment) or intrinsic (functional, structural, or degenerative).

Extrinsic risk factors

Training errors are among the major causes of plantar fasciitis. Athletes usually have a history of an increase in distance, intensity, or duration of activity. The addition of speed workouts, plyometrics, and hill workouts are particularly high-risk behaviors for the development of plantar fasciitis. Running indoors on poorly cushioned surfaces is also a risk factor.

Appropriate equipment is important. Athletes and others who spend prolonged time on their feet should wear an appropriate shoe type for their foot type and activity (see Treatment).[19] Athletic shoes rapidly lose cushioning properties.[20] Athletes who use shoe-sole repair materials are especially at risk if they do not change shoes often. Athletes who train in lightweight and minimally cushioned shoes (instead of heavier training flats) are also at higher risk of developing plantar fasciitis.

Intrinsic risk factors

Structural risk factors include pes planus, overpronation, pes cavus, leg-length discrepancy, excessive lateral tibial torsion, excessive femoral anteversion, and higher body mass index (BMI).[19, 21, 22, 3, 23]

Athletes with pes planus (low-arched) or pes cavus (high-arched) feet have increased stress placed on the plantar fascia with foot strike.[20] Pronation is a normal motion during walking and running, providing foot-to-ground surface accommodation and impact absorption by allowing the foot to unlock and become a flexible structure. Overpronation, on the other hand, can lead to increased tension on the plantar fascia.

Leg-length discrepancy, excessive lateral tibial torsion, and excessive femoral anteversion can lead to an alteration of running biomechanics, which may increase plantar fascia stress.

As regards functional risk factors, tightness in the hamstrings, gastrocnemius soleus, and the Achilles tendon are considered risk factors for plantar fasciitis.[24] Reduced dorsiflexion has been shown to be an important risk factor for this condition.[18] Weakness of the gastrocnemius, soleus, and intrinsic foot muscles is also considered a risk factor for plantar fasciitis.

Aging and heel fat pad atrophy are 2 degenerative risk factors for plantar fasciitis.

A survey of US professional football, baseball, and basketball team physicians and trainers found that plantar fasciitis was among the 5 most common foot and ankle injuries observed in professional athletes.[25] It is estimated that approximately 1 million patient visits per year are due to plantar fasciitis.[18] Plantar fasciitis accounts for about 10% of runner-related injuries and 11-15% of all foot symptoms requiring professional care. It is thought to occur in 10% of the general population as well. It may present bilaterally in a third of cases.

Age-, sex-, and race-related demographics

The exact incidence and prevalence by age of plantar fasciitis is unknown, but the condition is seen in adults essentially of all ages. A peak incidence may occur in women aged 40-60 years. An increased incidence exists in patients with certain spondyloarthropathies (eg, ankylosing spondylitis), which often present in patients aged 20-40 years.

Women are affected by plantar fasciitis twice as often as men. In young people, the condition occurs equally in both sexes. Race and ethnicity play no role in the incidence of plantar fasciitis.

About 80% of plantar fasciitis cases resolve spontaneously by 12 months; 5% of patients end up undergoing surgery for plantar fascia release because all conservative measures have failed.

For athletes in particular, the slow resolution of plantar fasciitis can be a highly frustrating problem. These individuals should be cautioned not to expect overnight resolution, especially if they have more chronic pain or if they continue their activities.[26] . Generally, the pain resolves with conservative treatment.[26, 27]

Although no mortality is associated with this condition, significant morbidity may occur. Patients may experience progressive plantar pain, leading to limping (antalgic gait) and restriction of activities such as walking and running. In addition, changes in weight-bearing patterns resulting from the foot pain may lead to associated secondary injury to the hip and knee joints.

Complications

In rare cases, the plantar fascia may rupture spontaneously. The risk of such a rupture is greatly increased by a history of treatment with a corticosteroid injection.[28]  Long-term sequelae of rupture occur in approximately 50% of the patients who have a plantar fascia rupture.[28, 29]  Moreover, longitudinal arch strain accounts for over 50% of the chronic complications of plantar fascia rupture.[28, 29]

Corticosteroid injection into the superficial fat pad may cause fat pad necrosis, due to loss of the shock absorption normally provided by the superficial fat pad, with subsequent pain during the early part of stance phase with ambulation. This development could create a significant disability in the event of a worker’s compensation case.

Potential complications include flattening of the longitudinal arch and heel hypoesthesia, as well as the potential complications that are associated with plantar fascia rupture. Longitudinal arch strain appears to account for over 50% of the chronic complications.[28, 29]

Patients should be informed that improvement often takes many weeks or months and requires considerable effort to maintain a heel-cord stretching program or to wear a night splint. They should also be taught proper performance of a home exercise program involving stretching the plantar fascia.

The following recommendations are appropriate:

• Wear shoes with adequate arch support and cushioned heels; discard old running shoes and wear new ones; rotate work shoes daily

• Avoid long periods of standing

• Lose weight

• Stretch the plantar fascia and warm up the lower extremity before participating in exercise

• For increased flexibility, stretch the plantar fascia and the calf after exercise

• Do not exercise on hard surfaces

• Avoid walking barefooted on hard surfaces

• Avoid high-impact sports that require a great deal of jumping (eg, aerobics and volleyball)

• Apply ice for 20 minutes after repetitive impact-loading activities and at the end of the day

• Limit repetitive impact-loading activities such as running to every other day, and consider rest or cross-training for nonrunning days

The sine qua non of plantar fasciitis is a history of intense sharp heel pain with the first couple of steps in the morning or after other long periods without weight-bearing.[8] Pain is experienced primarily on the plantar surface of the foot at the anterior aspect of the calcaneus, but it may radiate proximally in more severe cases. A limp may be present, and patients may prefer to walk on their toes. Associated paresthesias, nocturnal pain, or systemic symptoms should raise suspicion of other causes of heel pain (ie, neoplastic, infectious, neurologic causes).

Initially, the pain decreases with ambulation or athletic warmup, but then increases throughout the day as activity increases. In more severe cases, patients complain of heel pain after periods of prolonged sitting. A dull ache may be felt in the heel at the end of the day, especially after extensive walking or standing. In addition to pain, patients may complain of stiffness in the foot and localized swelling in the heel.

An important element in the history is the period preceding the start of plantar fasciitis. Patients may report that before the onset of pain, they had increased the amount or intensity of activity including, but not limited to, running or walking. They may have also started exercising on a different type of surface or may have recently changed footwear (eg, started a barefoot style running program). They may have sustained previous trauma to the foot (eg, falls, motor vehicle accidents, work-related injuries).

Any precipitating factors should be identified if possible. Ask the patient what makes the pain worse and what makes it better.

• Most patients report that the pain usually is most severe during the first few steps after prolonged inactivity, such as sleeping or sitting

• Patients may report that symptoms typically are relieved by unloading the affected foot (via sitting, elevation, or other means)

• Pain may be worsened by walking barefoot on hard surfaces or by walking up stairs

• In athletes, the pain may be particularly aggravated by sprinting

• Patients who are generally on their feet all day report that the symptoms may actually worsen by the end of the day

If this condition occurred in the course of the patient’s employment, then it may be considered a worker’s compensation issue. The physician should obtain a thorough history of the onset of the pain, any previous diagnostic assessment and/or treatments, and current functional capacities. This history is important for potential medicolegal purposes, such as impairment ratings.

The pain of plantar fasciitis can usually be reproduced by palpating the plantar-medial calcaneal tubercle at the site of plantar fascial insertion to the heel bone.[9] Less frequently, the pain will localize directly below the heel bone or even in the midsubstance of the plantar arch. In more severe cases, pain may be reproduced by palpation over the proximal portion of the plantar fascia.

A tight Achilles tendon (as in talipes equinus) is commonly a secondary finding and usually contributes to the pathology[9, 30] ; ankle dorsiflexion may be limited as a result.[31] Other findings may include various deformities, skin changes, and flat-foot or pes planus foot type, overpronation, pes cavus or high-arched foot type, leg-length discrepancy, excessive lateral tibial torsion, and excessive femoral anteversion.

Other maneuvers that may reproduce the pain of plantar fasciitis include passive dorsiflexion of the toes, which is sometimes called the windlass test, and having the patient stand on the tiptoes and toe-walk. In a study by De Garceau et al, having the patient bear weight during the windlass test (see the image below) increased the sensitivity of the test from 13.6% to 31.8%.[32]

Weight-bearing windlass test.

To ensure that the patient is not presenting with retrocalcaneal bursitis or Achilles tendonitis, the clinician also should palpate the posterior aspect of the heel and ankle to look for tenderness.

Reproduction of pain in the forefoot by compressing together the metatarsal heads of the second and third or the third and fourth toes suggests the presence of a Morton neuroma and is not a typical finding in plantar fasciitis. Morton neuroma is due to the entrapment of the common digital nerve between the metatarsal heads.

A full musculoskeletal examination, including range of motion of hind-foot joints and medial-to-lateral squeeze of the calcaneus, aids further in diagnosis. Pain with compression is more frequently seen in stress fracture.

Tarsal tunnel syndrome can be ruled out by percussing over the tarsal tunnel behind the medial malleolus. This test produces no pain in patients with plantar fasciitis. To rule out an S1 radiculopathy, perform the straight leg raise test, the Achilles tendon reflex, and calf strength assessment with toe-walking, or 1-legged heel raises. In patients with plantar fasciitis, the results of all of these tests are within the reference range.

The vascular examination includes palpation of the foot and ankle pulses. The Perthes test can be used to determine whether tortuous varicosities are contributing to the medial heel pain. In this test, a blood pressure cuff is inflated just proximal to the ankle at a pressure just below the patient’s systolic pressure, causing engorgement of symptomatic varicosities that may be entrapping the tibial nerve or causing claudication-type symptoms.

Usually, laboratory studies are not needed in the workup of plantar fasciitis. However, laboratory tests may be used to investigate other causes of heel pain if suspected.

Radiographs typically are not necessary for diagnosing plantar fasciitis. However, to rule out a bony tumor or fracture, always consider obtaining at least a plain radiograph before administering a corticosteroid injection.

Imaging studies may be helpful in defining the extent of the condition or in establishing the diagnosis if another disorder is suspected as the cause of the patient’s heel pain.[33] Ultrasound may be useful in following treatment response in chronic cases.[34]

No specific laboratory studies are needed to confirm the diagnosis of plantar fasciitis, unless there is a suspicion of an alternative cause, such as if there is a bilateral presentation that appears in association with some seronegative spondyloarthropathies. In such cases, the standard hematologic and chemistry studies may include, but are not limited to, a complete blood count (CBC), determination of the erythrocyte sedimentation rate (ESR), a complete metabolic panel, and rapid plasma reagin and rheumatoid factor studies.

Plain radiographs may reveal a plantar heel spur, which delineates the presence of abnormal stresses across the plantar fascia for at least 6 months.[30] Over time, the spur forms in a manner consistent with Wolff’s law—that is, “form follows function.” It is not the cause of the symptoms but, rather, a sequela of the process; thus, it does not require specific treatment or removal. About 50% of symptomatic patients and 20% of asymptomatic patients have heel spurs.[35, 36, 3] ; however, many patients with plantar fasciitis have no heel spur.

The heel spur is best seen on the lateral view, located at the anteroinferior aspect of the calcaneus. Radiographic films of the foot should be obtained before corticosteroid injection, as well as in any patient who continues to have symptoms despite 1-2 months of conservative, nonsurgical treatment (to ensure that a tumor or fracture has not been missed). Standing lateral radiographs may help in assessing the possibility of stress fractures of the calcaneus (a rare condition) in patients with pain at rest.

Magnetic resonance imaging

Reserve magnetic resonance imaging (MRI) for the rare cases in which imaging studies are needed to confirm plantar fasciitis or partial and complete plantar fascia rupture. Plantar fascia thickening and surrounding edema can also be detected on MRI.

Ultrasonography

Ultrasonography, though rarely used, can aid in the diagnosis of plantar fasciitis, much as MRI can. A marked increase in the thickness of the fascia (eg, from the normal 2-4 mm to 5-7 mm) may be noted. Other signs seen on ultrasonography include hypoechogenicity and edema of the fascia where it inserts into the calcaneus, as well as loss of definition between the fascia and the surrounding soft tissue. A more recent study has suggested that the finding of biconvexity on ultrasound may predict less response to treatment with mechanical support of the plantar fascia.[37] This study also found that increased thickness of the plantar fascia did not correlate well initially and especially as symptoms resolved. Another study found that although the presence of thickened plantar fascia and/or heel spurs tended to be associated with plantar fasciitis, these findings were also present in many asymptomatic individuals.[38]  

Bone scanning

Three-phase bone scanning is helpful for patients in whom there is a suggestion of a stress fracture of the calcaneus despite negative findings from plain radiography. In plantar fasciitis, a bone scan often shows increased uptake over the medial calcaneal tuberosity as a result of the local inflammation. This finding should not be confused with that of a stress fracture showing increased uptake elsewhere in the calcaneus. Bone scans are also used to evaluate for tumors and infection.

Computed tomography

If stress fracture remains a significant consideration despite negative radiographic findings, further imaging studies could include computed tomography (CT).

Electromyography

Electromyography (EMG) is useful to evaluate for possible neurologic entrapment syndromes.

Understanding the etiology of the problem and directing treatment accordingly is the key to successful treatment of plantar fasciitis. Close attention must be paid during the history and physical examination to ensure that other potential causes of heel pain are not missed. An organized, evidence-based, stepwise approach to treatment will help achieve good outcomes. Also essential is educating the patient about the expected time of recovery.

Plantar fasciitis is typically a self-limited condition, and studies have reported a resolution incidence of up to 90% with nonsurgical measures.[26, 39, 36, 40, 41, 42] However, patients have differing degrees of pathology and varying types of body habitus and lifestyle and will therefore respond differently to various treatments. Even with individualized care, some patients respond quickly, and others exhaust all conservative measures before relief is achieved.

The major component contributing to discomfort is the irritation occurring secondary to the disease process, rather than a spur or other mechanical factor. Traditional therapeutic efforts have been directed at decreasing the presumed inflammation. These treatments include icing, nonsteroidal anti-inflammatory drugs (NSAIDs), rest and activity modification, corticosteroids, botulinum toxin type A, splinting, shoe modifications, and orthoses.

Other treatment techniques have been directed at resolving the degeneration caused by the disease process. In general, these techniques are designed to create an acute inflammatory reaction with the goal of restarting the healing process. These techniques include autologous blood injection, platelet-rich plasma (PRP) injection, nitroglycerin patches, extracorporeal shock-wave therapy (ESWT), and surgical procedures. Formal physical therapy can include components that target both goals.

It is important to note that these treatment modalities are to be used in combination, as components of a multimodal therapeutic approach. Such an approach can be challenging, in that it places high expectations on the patient with respect to responsibility, consistency, and compliance. If these expectations are met, the chances of success are good.

Traditional treatment algorithms usually begin with 6 weeks of consistent and daily icing, stretching, NSAID therapy, strapping and taping, and over-the-counter (OTC) orthoses. Counseling as to activity modification, as well as choice of shoe gear, is important. After 6 weeks, recalcitrant cases should be treated additionally with a night splint and, possibly, an injection, along with the initial regimen for another 6 weeks.

If pain persists, referral to a foot and ankle specialist should be considered. Injection therapy, immobilization in a cast or walker boot, physical therapy, and custom orthotics can be employed under more controlled supervision. For severe recalcitrant cases, surgical intervention may ultimately be required.

A study looked to determine whether initial clinical findings could help predict patient response to conservative treatment primarily consisting of supportive footwear and stretching. The study reported that patients with severe ankle equinus were nearly four times more likely to experience a favorable response to treatment centered on home Achilles tendon stretching and supportive therapy.[43]

Ice is a first-line anti-inflammatory treatment for plantar fasciitis, especially for athletes. Icing should be performed after completing exercise, stretching, and strengthening, and this treatment can be applied via ice massage, ice bath, or ice pack, as follows:

• For ice massage, the patient freezes water in a small paper or polystyrene cup and then rubs the ice over the painful heel, using a circular motion and moderate pressure for 5-10 minutes.

• For an ice bath, a shallow pad is filled with water and ice, and the patient soaks the heel for 10-15 minutes; to prevent cold injuries, neoprene toe covers should be used, or the toes should be kept out of the ice water

• For an ice pack, crushed ice is placed in a plastic bag wrapped in a towel, then applied for 15-20 minutes; the use of crushed ice allows the pack to be molded to the foot, thereby increasing the contact area (a bag of prepackaged frozen corn kernels wrapped in a towel is a good alternative)

Rest is critical to the treatment of plantar fasciitis. This includes activity modification or a level of relative rest; complete rest may not be practical, particularly for more active individuals and for those whose jobs require standing. Alternative exercises or avoidance of inciting activities will increase the success rate of pain relief and of patient compliance. In patients with severe pain, a period of casting or immobilization in a walker boot may be necessary. In one study, 25% of patients considered rest to be the most effective form of treatment.[26]

Athletes with plantar fasciitis may return to activities as limited by their symptoms. However, they must modify activities that can aggravate plantar fasciitis (eg, walking, running, and jumping); such modifications may be as simple as decreasing the amount, frequency, or intensity of the inciting activity or activities. Athletes are more compliant with a decreased level of activity if they are allowed to increase other nonaggravating activities.[44]

The physician might need to plan a strict activities regimen because many athletes tend to ignore pain during activity. Generally, athletes should start at 50% of their usual distance or time with a gradual increase of activity by approximately 10% per week.

The following recommendations are appropriate for runners:

• Replacing worn-out shoes and selecting appropriate shoes are also important; runners should replace shoes every 250-500 miles (400-800 km) to maintain optimum shoe cushioning[20]

• Runners who overpronate and who have pes planus should select motion-control shoes, which typically feature a straight-lasted, board-lasted, or combination-lasted construction; an external heel counter; a wider flare; and extra medial support.[20]

• Runners who have pes cavus should select shoes that have greater cushioning properties

• All distance runners should practice in training flats that are better cushioned, reserving the lighter and less well-cushioned racing flats for competition.

• Runners whom are considering starting barefoot running style programs should be cautioned to start these runs at lengths and intensities as if they are beginning runners.

NSAIDs

Anti-inflammatory medications are frequently used to treat plantar fasciitis. Although there is controversy as to whether NSAIDs actually assist in the physiologic healing process, these agents can be useful as an adjunct for controlling pain while the individual’s plantar fasciitis is being treated with stretching, strengthening, and relative rest.[26, 45]

In one study, 79% of patients were successfully treated with NSAIDs.[26] The key to NSAID therapy is consistent, daily dosing throughout the acute phase of treatment. Risks such as gastrointestinal (GI) sequelae, gastric pain, and renal damage have been well documented.[46] Use NSAIDs with caution in elderly patients, monitoring for the most common adverse effects and for any drug interactions. Oral NSAIDs should be avoided during pregnancy.

Corticosteroids

Corticosteroids can be administered either orally or via injections. Oral preparations, such as a methylprednisolone dose pack, are distributed systemically and can be used in the acute phase in conjunction with, or in place of, NSAIDs.

Corticosteroid injections, on the other hand, involve local, concentrated administration and are generally reserved as a tertiary level of treatment after failure of other primary conservative measures (eg, stretching, shoe inserts, or orthoses) in severe recalcitrant cases.[47, 48, 49] Whether or not injected corticosteroids alter the long-term pathology of chronic inflammation, many patients experience acute symptomatic improvement.[45, 50, 51] One study found that ultrasound (US)-guided steroid injection provided short-term relief from pain in plantar fasciitis for up to 4 weeks and improvement in plantar fascia swelling for up to 12 weeks.[52, 53] Whether or not the use of ultrasound guidance improves outcome of corticosteroid injections is unknown at this time.[54, 55, 56] A single-blinded, randomized, controlled trial of 90 patients found that at 2-year follow-up a combination of injected corticosteroid and physical therapy was superior to either of the treatments alone.[53]

Before steroids are injected, potential causes of heel pain other than plantar fasciitis should also be considered, and a plain radiograph of the foot or calcaneus should always be obtained.

A corticosteroid injection may be given through a plantar or a medial approach, with or without ultrasound guidance, typically in conjunction with a local anesthetic. The basic technique may be briefly summarized as follows:

• Use a 22-gauge, 1.5-in. (3.8-cm) needle containing a mixture of 4 mL of local anesthetic (eg, lidocaine) and 1 mL (40 mg) of corticosteroid (eg, methylprednisolone)

• 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 within the superficial layers of the subcutaneous tissue, because corticosteroid injection into the superficial fat pad can cause fat necrosis and atrophy, which reduce the shock-absorbing capacity of the plantar heel

Studies have reported success rates of 70% or better.[39, 57]  Corticosteroid injections have been shown to improve symptoms at 1 month but not at 6 months. It is recommended not to give more than 3 steroid injections within a year.

A randomized, controlled study demonstrated that intralesional corticosteroid injection is more efficacious and more cost-effective than low-energy ESWT in the treatment of plantar fasciitis that has persisted for more than 6 weeks.[58]

In a preliminary report, a posterior tibial nerve block prior to steroid injection was shown to decrease the pain from injection and to improve compliance with treatment, without any complications.[59]

Trials of ultrasound-guided steroid injection have shown its potential efficacy. This approach has been shown to produce a good clinical response when palpation-guided injection is unsuccessful.[57] Accurate injection under ultrasonographic guidance may also minimize adverse effects from the injection.[60]

A study of 25 patients who received corticosteroid injections for plantar fasciitis showed that patients received symptomatic relief as measured by tenderness threshold and a visual analog scale (VAS).[60] Although this benefit was obtained whether the injection was performed with imaging (ultrasound) guidance or with palpation alone, patients receiving image-guided injections had a lower rate of recurrence of heel pain. Thus, although injection is helpful with or without imaging guidance, the use of imaging may provide additional benefit.

Overall, it would appear that while cortisone is effective in providing short term pain relief, ultimately there is no significant difference in outcome from other treatments.[61, 62]

The general risks involved with the use of corticosteroids include skin atrophy, skin hypopigmentation, soft-tissue atrophy, infection, bleeding, and failure to work. A steroid flare-up, which consists of increased pain for up to several days, may occur in up to 2% of individuals who use corticosteroids.[50]

Potential risks of corticosteroid injection include plantar fascia rupture, which was found in almost 10% of patients after plantar fascia injection in one case series,[28] and fat pad atrophy.[28, 29] Long-term sequelae were found in approximately 50% of patients with plantar fascia rupture.[28]

Improper placement of a corticosteroid injection for plantar fasciitis can result in necrosis and atrophy of the plantar fat pad at the heel. This complication may result in significant pain and a decreased activity level for the patient.

Bleeding or bruising generally is expected only in patients who have bleeding disorders or are taking anticoagulants. Infection at the injection site is rare, but possible. In addition to the sterile technique for the procedure itself, patients need to maintain good foot hygiene after the injection. Allergic reactions to the injected medications are rare, but possible.

Intravascular injection could potentially cause cardiac dysfunction as a consequence of the inherent toxicity of local anesthetic agents. Peripheral nerve dysfunction is possible if the local anesthetic is injected either close to or within the medial plantar nerve or the calcaneal branch of the tibial nerve.

In diabetic patients, transient elevation of blood glucose levels may occur after corticosteroid injection. Corticosteroid injection can be performed during pregnancy, although safety for use during pregnancy has not been established. With pediatric patients, obtain informed consent from the parent or legal guardian before proceeding with examination or any injection.

Patients should be informed that the symptomatic improvement from the corticosteroid usually does not begin to take effect until a few days after the injection. They may experience a transient, mild increase in symptoms when the effect of the short-term local anesthetic has ended, but the long-term corticosteroid effect has not yet begun.

Finally, they should be educated to watch for any signs or symptoms of local infection at the injection site, while maintaining good skin hygiene.

Botulinum toxin type A

Several short-term, randomized, controlled, double-blind studies found that botulinum toxin type A injection appeared to yield significant improvements in pain relief and overall foot function.[63, 64, 65, 66] One of these studies found that ultrasound-guided injection of botulinum toxin type A did not induce the complication of fat pad atrophy and was successful at improving the maximal center of pressure loading in the foot.[64] A double-blind, randomized, controlled study of 50 patients with plantar fasciitis compared the injection of botulinum toxin type A to saline injection and found that there was significant improvement in VAS pain scores and plantar fascia thickness at both the 3-week and the 3-month follow-up visits.[64] A 6-month, randomized, controlled, double-blind study that compared botulinum toxin type A injection to corticosteroid injection in 36 patients found a more rapid and sustained response in the botulinum toxin–injected group.[65]

Autologous blood and plasma

Injection of autologous blood into the plantar fascia origin is thought to stimulate an acute inflammatory reaction, providing factors that stimulate fibroblast activity and vascular growth and thereby lead to reinitiation of the healing process. This treatment has been shown to be effective in limited studies of chronic inflammatory musculotendinous conditions.[67, 68, 69]

There is some evidence to suggest that platelet-rich plasma (PRP) may be beneficial in the treatment of chronic plantar fasciitis.[70, 71, 72, 73, 61] Most of the studies that compared corticosteroid injection with either autologous blood or PRP injections appear to show that while corticosteroids may provide better short-term relief, autologous blood and PRP injections have better long-term results.[52, 74, 75, 76, 77, 78, 79, 52, 80, 81] On the other hand, studies concluded that the results of PRP were only equivalent to corticosteroid injection[82] or placebo.[83]

Cryopreserved human amniotic membrane

One newer, experimental treatment involves the injection of cryopreserved human amniotic membrane. This fetal tissue is believed to contain growth factors, cytokines, and matrix components, which promote soft tissue healing. A randomized, controlled, double-blind, pilot study of 23 patients found equivalent results to the control group, which had been injected with corticosteroid, at the 12-week follow-up.[84]

Prolotherapy

Although the technique of prolotherapy injection has been used for many decades, research is scant. A more recent double-blinded, randomized, controlled study of 65 patients showed good relief at 7- and 15-week follow-up visits.[85]

ESWT has been proposed as a treatment option for plantar fasciitis. The therapy bombards the tissue with high-pressure sound waves with its mechanism of action being to (1) stimulate blood flow for a beneficial immune response, (2) reinjure tissue to stimulate healing, and (3) shut down the neuronal pain pathways through the pulses hitting the affected nerves.

Although ESWT has not been definitively shown to be effective, it has been approved by the US Food and Drug Administration (FDA) for the treatment of plantar fasciitis and tennis elbow. ESWT is noninvasive, has few adverse effects, and is associated with a good recovery time in patients with chronic plantar fasciitis; however, it is not covered by most insurance plans.

In 2013, two meta-analyses concluded that ESWT could be a safe and effective nonsurgical treatment for plantar fasciitis.[86, 87] Some studies show favorable results with ESWT but recommend that it be used only after other noninvasive, proven measures have failed.[88] Although multiple studies have shown success rates of 50-90%,[89, 90, 91, 92, 93, 61, 94] overall, study results have been mixed.[95, 96, 88, 97, 98, 47, 48, 99, 100, 101, 102]

One study used low-frequency electrical stimulation to safely treat pain and increase functional activity levels in patients with plantar fasciitis.[103, 104]

Another study showed that ESWT induces an immediate analgesic and anti-inflammatory effect, as well as long-term tissue regeneration. ESWT has been observed to increase blood flow in the treated area, and preliminary data indicate increased endothelial nitric oxide levels as the mechanism. After 4-8 weeks of treatment, ESWT was also found to increase neoangiogenesis in the tendons of dogs; further research in this area is needed.[105]

Focused ESWT seems to be superior to radial ESWT.[106] However, a study that compared shockwave treatment with conventional physiotherapy for treating plantar fasciitis showed that whereas shockwave treatment yielded earlier pain reduction and functional improvement, it was no more effective than conventional physiotherapy 3 months after the end of treatment.[107]

In 2013, three different meta-analysis studies concluded that ESWT was effective compared to placebo.[108, 109, 110]

A pilot study suggests that intracorporeal pneumatic shock treatment (IPST) may be used in patients with chronic plantar fasciitis that does not respond to conservative management. IPST may be considered before surgery when ESWT devices are not available. A randomized, double-blind, prospective clinical pilot study showed that IPST is safe and effective; however, the exact mechanism is unknown and thus warrants further research.[111]

Laser therapy is a newer technique that has not been well studied. Theoretically, low-level lasers are supposed to stimulate metabolism via the inflammatory pathways. A meta-analysis of 6 randomized controlled trials suggests that low-level laser therapy might provide short-term pain relief.[112]

Night splints

Most people naturally sleep with their feet in a plantar-flexed position, which causes the plantar fascia to be shortened. Night splints maintain a neutral 90° foot-leg angle and provide constant passive stretching of the Achilles tendon and plantar fascia.[113] Their effectiveness is believed to derive from the rest and healing provided by the constant stretching. In addition, the passive stretching helps prevent microtrauma at the plantar fascia–bone interface with the first steps out of bed in the morning.

A night splint can be molded from either plaster or fiberglass casting material, or a prefabricated and commercially produced plastic brace can be used (see the image below).

Night splint, designed to prevent shortening of Achilles tendon and plantar fascia at night.

A number of studies have shown that a high percentage of patients using night splints had improvement of their plantar fasciitis.[114, 115, 116, 117, 118, 119, 120] Regarding the difficulty of patient compliance with night splints, a prospective trial showed that the comfort afforded by the night splint resulted in 95% patient compliance.[118] Some studies suggest that the splints are especially useful in individuals who have had symptoms of plantar fasciitis for longer than 12 months.[114, 115, 116, 117]

Casts or splints holding the ankle in neutral to slight dorsiflexion have been investigated, although their efficacy remains to be determined.

Shoe modifications and orthotics

A supportive heel counter and stiff midsole are important components of any shoe for those experiencing heel pain. Fashionable shoe wear often does not provide sufficient support for the arch and further exacerbates the problem. Better cushioned footwear may also decrease symptoms of plantar fasciitis.[121] A randomized, double-blind study comparing patients' sandals with and without arch support found significant improvement in pain and function in the group with the arch supports.[122] In general, lace-up shoe gear is recommended to maximize support. In one study,[26]  14% of patients credited change in shoe gear as the best treatment.

Shoe inserts (see the images below) can be used with existing shoes. Orthoses may be purchased over the counter or can be custom made. In general, over-the-counter (OTC) and custom-made orthoses appear to be equally effective in treating plantar fasciitis.[123, 124, 125, 126, 113, 127, 120] However, one randomized, controlled trial found that ethylene vinyl acetate (EVA) prefabricated inserts may be more beneficial than custom-made ones in uncomplicated plantar fasciitis.[128] One randomized, prospective study found that more supportive orthotics resulted in better pain relief when compared with softer, non-supportive orthotics[129] ; on the other hand, another found both hard and soft orthotics provided equal relief.[130]

A systematic review and meta-analysis by Whittaker et al that included 19 trials (1660 participants) reported that in the medium term (7 to 12 weeks), there was moderate-quality evidence that foot orthoses are effective at reducing plantar heel pain in adults. In the short and longer term (0 to 6 weeks and 13 to 52 weeks), there was low-quality evidence that foot orthoses reduce pain or improve function.[131]

Example of arch support with cushioned heel. These are available in three-quarter or full lengths to fit in shoe.

Orthosis

Patients with low arches experience increased stress on the plantar fascia with foot strike and have a decreased ability to absorb the forces that are generated by foot strike.[20] Mechanical corrections for pes planus include taping of the arches, OTC arch supports, and custom orthotic devices. Studies have found significant benefit to these conservative treatments when they are used in appropriate patients.[26, 132, 127, 133, 120, 130]

Low-dye strapping with athletic tape (see the image below) can be used as a definitive treatment or as a trial to determine whether the expense of arch supports or orthotics is worthwhile. Taping may be more cost-effective for the acute onset of plantar fasciitis, whereas OTC arch supports and orthotics may be more cost-effective for chronic or recurrent cases of plantar fasciitis and for the prevention of injuries. Heel pads are widely used, but they are generally useful only for shock absorption and do not provide support or structural control.[134] A meta-analysis concluded that kinesiotaping was no more effective than standard taping techniques.[135]

Low-dye taping method. This technique provides support for plantar fascia and helps reduce excessive pronation.

OTC arch supports usually last a full athletic season; custom orthotic devices should last many seasons. OTC arch supports are especially useful in athletes with acute plantar fasciitis and mild pes planus, particularly adolescents whose rapid foot growth may necessitate the purchase of 1 or more new pairs of arch supports per season.

Custom orthotic devices are designed to control biomechanical risk factors such as pes planus, valgus heel alignment, and leg-length discrepancies. Athletes treated with orthotic devices usually require semirigid, three-quarter to full-length orthotic devices with longitudinal arch support to control overpronation and metatarsal head motion, especially of the first metatarsal head.[136] The main disadvantage to the use of orthotic devices is the cost, which ranges from $75 to $300 or more; frequently, these devices are not covered by insurance. Studies have suggested that over-the-counter insoles are often as effective as these custom orthotics[137] or are not needed at all.[138]

As a second level of treatment, formal physical therapy can help get the patient obtain long-term pain relief if he or she is unable to do so on his or her own. Contrast baths, ultrasonography, and iontophoresis may be used as adjuncts. In one study, iontophoresis was found to increase the speed of resolution of plantar fasciitis, though it had no effect on long-term outcome.[139]

For convenience, physical therapy programs may be divided into stretching, strengthening, and maintenance phases.

Stretching

The initial physical therapy program for plantar fasciitis emphasizes stretching of the calf and foot. Although the exact benefits are unknown,[140] one study found that 83% of patients treated with stretching exercises experienced successful relief.[26] Accordingly, stretching of the Achilles tendon has become a key component in the resolution of heel pain.

Wall stretching (the runner’s stretch) with the knee in both the extended and flexed positions, stair stretching, and towel stretching are all commonly employed. To perform a wall stretch, the patient stands 3 feet from a wall, placing the hands on the wall. Keeping the toes pointed straight and the heel on the ground, the patient leans the hips toward the wall, then holds this position for 30-40 seconds (see the image below).[8]

Calf stretch.

Stretches targeted at the plantar fascia (see the image below) are particularly important. A level 2 clinical trial led by DiGiovanni et al studied the effect of passive dorsiflexion on the toes with simultaneous stretching of the Achilles tendon.[141] Recruiting the extension of the toes and subsequently engaging the windlass mechanism increased the effectiveness of the traditional stretching regimen, as well as subsequent symptom relief.

Plantar fascia stretching exercise.

Strengthening

A strengthening program that emphasizes intrinsic foot muscle strengthening has also proved beneficial.[27] . Exercises to strengthen the intrinsic muscles include towel curls, marble (or coin) pickups, and toe taps.[8]

For a towel curl, the patient sits with the affected foot lying flat on the end of a towel that is placed on a smooth surface, then pulls the towel toward the body by using the toes to curl up the towel while keeping the heel on the floor (see the image below). As the patient’s ability to perform this exercise improves, weight may be added to the far end of the towel to increase the difficulty.

Towel curl.

For marble pickups, the patient places a few marbles on the floor near a cup, picks them up with the toes, and drops them in the cup while keeping the heel on the floor. To provide a greater challenge, coins may be substituted for the marbles.

For toe taps, the patient lifts all the toes off the floor and, while keeping the heel on the floor and the outside 4 toes in the air, repetitively taps just the big toe to the floor (see the image below). Next, the patient reverses the process and repetitively taps the outside 4 toes to the floor while keeping the big toe in the air.

Toe taps.

Maintenance

To minimize the likelihood that plantar fasciitis will recur, athletes should continue on a maintenance program of daily stretching or strengthening at least 2-3 times per week.

In 5-10% of cases of plantar fasciitis, surgery may be required.[40, 39, 41, 142] It is reserved for those in whom a thorough 6-12 months of conservative treatment has failed. Plantar fascia release—performed by sectioning part or all of the fascia via an open or endoscopic procedure—has been the mainstay of treatment.[143, 144] However, partial and, especially, total release of the plantar fascia results in instability of the medial column of the foot, along with lateral column overload and pain.[145]

Overall, surgical release has a 70-90% success rate in treating patients with this condition.[146, 147, 148, 149, 150, 151, 152] A study by Bazaz and Ferkel found that endoscopic plantar fascia release provided significantly improved outcomes for patients, specifically those with less severe symptoms.[153]

Potential complications of surgical intervention include flattening of the longitudinal arch and heel hypoesthesia, in additions to the complications associated with plantar fascia rupture and corticosteroid injections. Longitudinal arch strain appears to account for over 50% of the chronic complications.[28, 29]

Percutaneous partialfasciotomy

In a series of 55 patients, percutaneous variation of medial fascial release appeared to have similar long-term pain outcomes to open fasciotomy with quicker return to activity.[154]

Cryosurgery

Cryosurgery is a relatively new technique in which a small cryoprobe is inserted percutaneously and used to destroy pathologic tissue or cells at temperatures reaching -70° C. A prospective study of 61 cases suggests that this modality is an effective treatment for plantar fasciitis after failed conservative management.[155] A larger study of study of 137 feet reported a 77% success rate with cryosurgery at 2-year follow-up.[156]

Bipolar radiofrequency microdebridement

Another relatively new percutaneous technique is Topaz bipolar radiofrequency microdebridement, which applies a bipolar radiofrequency pulse to the plantar fascia. In comparison to traditional surgical interventions, this new technology has been yielding equivalent results, with the advantages of decreased morbidity, earlier pain relief, lack of wound infection, absence of lateral column pain, and earlier time to weight-bearing.

In one study, patients achieved an average American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot score of 92 out of a possible 105 at an average of 11 months after operation.[157] In another small study of 31 feet, radiofrequency nerve ablation resulted in significant improvement in VAS scores at 1 week, 1 month, 3 month, and 6 months.[158] Long-term, randomized, double-blind studies are still needed. As with any surgical procedure, the risk-benefit ratio must be determined.

A relatively new option for recalcitrant plantar fasciitis is radiation therapy. Studies of this treatment are relatively limited, but preliminary outcomes are positive. Long-term effects are still unknown.[159, 160]

Education is the single most important means of preventing plantar fasciitis. Instruct athletes with plantar fasciitis to warm up sufficiently before initiating activity, continue stretching programs, and ice down after activity. Patients may need to decrease their running temporarily; later, they may resume their earlier level of activity at the discretion of the physician and physical therapist.

Make sure that sports-minded patients wear appropriate shoes and change to a new pair every 250-500 miles (400-800 km).[20] Alternating between 2 pairs of shoes seems to help some athletes by allowing the cushioning in the shoes to recover more completely between runs. Adequate padding, proper sole stiffness, and appropriate arch support all can help alleviate symptoms.

In cases of occupationally related plantar fasciitis, evaluation of the worker’s shoes and work environment is essential for preventing a recurrence of this musculoskeletal condition.[19]

In general, patients should return for reevaluation no sooner than 2 months after the initial evaluation and implementation of a rehabilitation program since progress is typically slow. Occasionally, patients requiring more aggressive treatment because of severe disruption of their athletic, occupational, or recreational activities may need to be seen more frequently, mainly so that the caregiver can provide reassurance and chart the progress of therapeutic interventions.

At the time of follow-up, assess the therapeutic response to the corticosteroid injection, and evaluate for any complications.

The overall goals of pharmacotherapy in patients with plantar fasciitis are to reduce morbidity and prevent complications. Medications are used primarily to decrease pain and inflammation. The most commonly used medications are oral nonsteroidal anti-inflammatory drugs (NSAIDs) and corticosteroid injections, which may be employed in conjunction with physical therapy.

Class Summary

NSAIDs have analgesic, anti-inflammatory, and antipyretic activities. Their mechanism of action is not known, but they may inhibit cyclooxygenase (COX) activity and prostaglandin synthesis. Other mechanisms may exist as well, such as inhibition of leukotriene synthesis, lysosomal enzyme release, lipoxygenase activity, neutrophil aggregation, and various cell-membrane functions.

NSAIDs can help decrease pain and inflammation in patients with plantar fasciitis. Various oral NSAIDs can be used; there are no particular drugs of choice. The choice of NSAID is largely a matter of convenience (eg, the frequency with which doses must be taken to achieve adequate analgesic and anti-inflammatory effects) and cost.

Ibuprofen (Motrin, I-Prin, Advil, Caldolor)

Ibuprofen is a member of the propionic acid group of NSAIDs. It is available in a low-dose form as an over-the-counter (OTC) medication. It is highly protein-bound, is metabolized in the liver, and is eliminated primarily in the urine.

Ibuprofen is used for analgesia and anti-inflammatory effect and is the drug of choice for patients with mild to moderate pain. It inhibits inflammatory reactions and pain by decreasing prostaglandin synthesis. It may reversibly inhibit platelet function.

Naproxen (Aleve, Anaprox, Naprosyn, Naprelan)

Naproxen is a member of the propionic acid group of NSAIDs. It is available in low-dose form as an OTC medication. It is highly protein-bound, is metabolized in the liver, and is eliminated primarily in the urine. Naproxen may reversibly inhibit platelet function.

Sulindac (Clinoril)

Sulindac decreases COX activity and, in turn, inhibits prostaglandin synthesis. This results in decreased formation of inflammatory mediators.

Celecoxib (Celebrex)

Celecoxib primarily inhibits COX-2. COX-2 is considered an inducible isoenzyme, induced during pain and inflammatory stimuli. Inhibition of COX-1 may contribute to NSAID gastrointestinal (GI) toxicity. At therapeutic concentrations, COX-1 isoenzyme is not inhibited; thus, GI toxicity may be decreased. Seek the lowest dose of celecoxib for each patient.

Meloxicam (Mobic)

Meloxicam decreases COX activity, and this, in turn, inhibits prostaglandin synthesis. These effects decrease the formation of inflammatory mediators.

Ketoprofen

Ketoprofen is used for relief of mild to moderate pain and inflammation. Small dosages are indicated initially in small patients, elderly patients, and patients with renal or liver disease. Doses higher than 75 mg do not increase the therapeutic effects. Administer high doses with caution, and closely observe the patient's response.

Flurbiprofen

Flurbiprofen may inhibit COX, thereby, in turn, inhibiting prostaglandin biosynthesis. These effects may result in analgesic, antipyretic, and anti-inflammatory activities.

Class Summary

In contrast to the widespread systemic distribution achieved with oral administration of an anti-inflammatory drug, local injection of a corticosteroid can achieve focal placement of a potent anti-inflammatory agent at the site of maximal tenderness or inflammation. Various corticosteroid preparations from which to choose. Commonly, the corticosteroid is mixed with a local anesthetic agent before injection. Again, there are various local anesthetic agents from which to choose.

Triamcinolone (Aristospan, Kenalog-10, Kenalog-40)

Triamcinolone is an injectable corticosteroid anti-inflammatory agent used to treat localized areas of inflammation. It has an intermediate duration of action.

Betamethasone sodium (Celestone, Soluspan)

Betamethasone is an injectable corticosteroid anti-inflammatory agent used to treat localized areas of inflammation. It has an intermediate duration of action.

Methylprednisolone (Depo-Medrol, A-Methapred, Medrol)

Methylprednisolone decreases inflammation by suppressing migration of polymorphonuclear leukocytes and reducing capillary permeability. It is commonly given via local injection of bursae or joints to provide a local anti-inflammatory effect while minimizing some of the GI and other risks of systemic medications.