Plantar fasciitis

Plantar fasciitis
Synonyms	plantar fasciosis, plantar fasciopathy, jogger's heel
Classification and external resources
Specialty	Orthopedics, sports medicine, plastic surgery, podiatry
ICD-10	M72.2
ICD-9-CM	728.71
DiseasesDB	10114
MedlinePlus	007021
eMedicine	pmr/107 orthoped/142
Patient UK	Plantar fasciitis
MeSH	D036981

Plantar fasciitis is a disorder that results in pain in the heel and bottom of the foot.^[1] The pain is usually most severe with the first steps of the day or following a period of rest.^[2] Pain is also frequently brought on by bending the foot and toes up towards the shin and may be worsened by a tight Achilles tendon.^[2][3] The condition typically comes on slowly.^[3] In about a third of people both legs are affected.^[1] Typically there are no fevers or night sweats.^[3]

The causes of plantar fasciitis are not entirely clear. Risk factors include overuse such as from long periods of standing, an increase in exercise, and obesity.^[1] It is also associated with inward rolling of the foot and a lifestyle that involves little exercise.^[1][2] While heel spurs are frequently found it is unclear if they have a role in causing the condition. Plantar fasciitis is a disorder of the insertion site of the ligament on the bone characterized by micro tears, breakdown of collagen, and scarring.^[1] As inflammation plays a lesser role, many feel the condition should be renamed plantar fasciosis.^[1][4] The diagnosis is typically based on signs and symptoms with ultrasound sometimes used to help.^[1] Other conditions with similar symptoms include osteoarthritis, ankylosing spondylitis, heel pad syndrome, and reactive arthritis.^[5][6]

Most cases of plantar fasciitis resolve with time and conservative methods of treatment.^[2][7] Usually for the first few weeks people are advised to rest, change their activities, take pain medications, and stretch. If this is not sufficient physiotherapy, orthotics, splinting, or steroid injections may be options. If other measures do not work extracorporeal shockwave therapy or surgery may be tried.^[2]

Between 4% and 7% of people have heel pain at any given time and about 80% of these cases are due to plantar fasciitis.^[1][5] Approximately 10% of people have the disorder at some point during their life.^[8] It becomes more common with age. It is unclear if one sex is more affected than the other.^[1]

Signs and symptoms

When plantar fasciitis occurs, the pain is typically sharp^[9] and usually unilateral (70% of cases).^[7] Heel pain is worsened by bearing weight on the heel after long periods of rest.^[10] Individuals with plantar fasciitis often report their symptoms are most intense during their first steps after getting out of bed or after prolonged periods of sitting.^[2] Improvement of symptoms is usually seen with continued walking.^[2][6][9] Rare, but reported symptoms include numbness, tingling, swelling, or radiating pain.^[11]

If the plantar fascia continues to be overused in the setting of plantar fasciitis, the plantar fascia can rupture. Typical signs and symptoms of plantar fascia rupture include a clicking or snapping sound, significant local swelling, and acute pain in the sole of the foot.^[9]

Risk factors

Identified risk factors for plantar fasciitis include excessive running, standing on hard surfaces for prolonged periods of time, high arches of the feet, the presence of a leg length inequality, and flat feet. The tendency of flat feet to excessively roll inward during walking or running makes them more susceptible to plantar fasciitis.^[2][10][12] Obesity is seen in 70% of individuals who present with plantar fasciitis and is an independent risk factor.^[3] Studies have suggested a strong association exists between an increased body mass index and the development of plantar fasciitis in the non-athletic population; this association between weight and plantar fasciitis has not been observed in the athletic population.^[7] Achilles tendon tightness and inappropriate footwear have also been identified as significant risk factors.^[13]

Pathophysiology

Drawing of the plantar fascia of the foot

The cause of plantar fasciitis is poorly understood and is thought to likely have several contributing factors.^[13] The plantar fascia is a thick fibrous band of connective tissue that originates from the medial tubercle and anterior aspect of the heel bone. From there, the fascia extends along the sole of the foot before inserting at the base of the toes, and supports the arch of the foot.^[3][10][12]

Originally, plantar fasciitis was believed to be an inflammatory condition of the plantar fascia. However, within the last decade, studies have observed microscopic anatomical changes indicating that plantar fasciitis is actually due to a noninflammatory structural breakdown of the plantar fascia rather than an inflammatory process.^[7][13]

Due to this shift in thought about the underlying mechanisms in plantar fasciitis, many in the academic community have stated the condition should be renamed plantar fasciosis.^[6] The structural breakdown of the plantar fascia is believed to be the result of repetitive microtrauma (small tears).^[11][12] Microscopic examination of the plantar fascia often shows myxomatous degeneration, connective tissue calcium deposits, and disorganized collagen fibers.^[4]

Disruptions in the plantar fascia's normal mechanical movement during standing and walking (known as the Windlass mechanism) are thought to contribute to the development of plantar fasciitis by placing excess strain on the calcaneal tuberosity.^[13] Other studies have also suggested that plantar fasciitis is not actually due to inflamed plantar fascia, but may be a tendon injury involving the flexor digitorum brevis muscle located immediately deep to the plantar fascia.^[12]

Diagnosis

Achilles tendon tightness is a risk factor for plantar fasciitis. It can lead to decreased dorsiflexion of the foot.

Heel bone with heel spur (red arrow)

Thickened plantar fascia in ultrasound

Plantar fasciitis is usually diagnosed by a health care provider after consideration of a person's presenting history, risk factors, and clinical examination.^[2][14][15] Tenderness to palpation along the inner aspect of the heel bone on the sole of the foot may be elicited during the physical examination.^[2][10] The foot may have limited dorsiflexion due to tightness of the calf muscles or the Achilles tendon.^[7] Dorsiflexion of the foot may elicit the pain due to stretching of the plantar fascia with this motion.^[2][11] Diagnostic imaging studies are not usually needed to diagnose plantar fasciitis.^[7] However, in certain cases a physician may decide imaging studies (such as X-rays, diagnostic ultrasound or MRI) are warranted to rule out serious causes of foot pain.

Other diagnoses that are typically considered include fractures, tumors, or systemic disease if plantar fasciitis pain fails to respond appropriately to conservative medical treatments.^[2][10] Bilateral heel pain or heel pain in the context of a systemic illness may indicate a need for a more in-depth diagnostic investigation. Diagnostic tests such as a CBC or serological markers of inflammation, infection, or autoimmune disease such as C-reactive protein, erythrocyte sedimentation rate, anti-nuclear antibodies, rheumatoid factor, HLA-B27, uric acid, or Lyme disease antibodies may also be obtained.^[5] Neurological deficits may prompt an investigation with electromyography to evaluate for damage to the nerves or muscles.^[11]

An incidental finding associated with this condition is a heel spur, a small bony calcification on the calcaneus (heel bone), which can be found in up to 50% of those with plantar fasciitis.^[6] In such cases, it is the underlying plantar fasciitis that produces the heel pain, and not the spur itself.^[12] The condition is responsible for the creation of the spur though the clinical significance of heel spurs in plantar fasciitis remains unclear.^[11]

Imaging

Medical imaging is not routinely needed as it is expensive and does not typically change how plantar fasciitis is managed.^[13] When the diagnosis is not clinically apparent, lateral view x-rays of the ankle are the recommended imaging modality to assess for other causes of heel pain such as stress fractures or bone spur development.^[7]

Normally the plantar fascia has three fascicles with the central fascicle thickest at 4 mm, the lateral fascicle at 2 mm and the medial at less than a millimeter in thickness.^[16] In theory, the likeliness of fasciitis increases with increasing thickness of plantar fascia at the calcaneal insertion, with thickness of more than 4.5 mm being somewhat useful on ultrasound and 4 mm on MRI.^[17] Findings on imaging such as plantar aponeurosis thickening, however, may be absent in symptomatic individuals or present in asymptomatic individuals thereby limiting the utility of such observations.^[12]

3-phase bone scan is a sensitive modality to detect active plantar fasciitis. Furthermore, 3-phase bone scan can be used to monitor response to therapy, as demonstrated by decreased uptake after corticosteroid injections.^[18]

Differential diagnosis

The differential diagnosis for heel pain is extensive and includes pathological entities including, but not limited to the following: calcaneal stress fracture, calcaneal bursitis, osteoarthritis, spinal stenosis involving the nerve roots of lumbar spinal nerve 5 (L5) or sacral spinal nerve 1 (S1), calcaneal fat pad syndrome, hypothyroidism, seronegative spondyloparthopathies such as reactive arthritis, ankylosing spondylitis, or rheumatoid arthritis (more likely if pain is present in both heels),^[5] plantar fascia rupture, and compression neuropathies such as tarsal tunnel syndrome or impingement of the medial calcaneal nerve.^[3][5][7]

A determination about a diagnosis of plantar fasciitis can usually be made based on a person's medical history and physical examination.^[19] In cases in which the physician suspects fracture, infection, or some other serious underlying condition, an x-ray may be used to make a differential diagnosis.^[19] However, and especially for people who stand or walk a lot at work, x-rays should not be used to screen for plantar fasciitis unless imaging is otherwise indicated as using it outside of medical guidelines is unnecessary health care.^[19]

Treatment

Non-surgical

About 90% of plantar fasciitis cases will improve within six months with conservative treatment,^[8] and within a year regardless of treatment.^[2][7] Many treatments have been proposed for plantar fasciitis. Most have not been adequately investigated and there is little evidence to support recommendations for such treatments.^[2] First-line conservative approaches include rest, heat, ice, and calf-strengthening exercises; techniques to stretch the calf muscles, Achilles tendon, and plantar fascia; weight reduction in the overweight or obese; and nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin or ibuprofen.^[6][10][20] NSAIDs are commonly used to treat plantar fasciitis, but fail to resolve the pain in 20% of people.^[10]

Extracorporeal shockwave therapy (ESWT) is an effective treatment modality for plantar fasciitis pain unresponsive to conservative nonsurgical measures for at least three months. Evidence from meta-analyses suggests significant pain relief lasts up to one year after the procedure.^[8][21] However, debate about the therapy's efficacy has persisted.^[4] ESWT can be performed with or without anesthesia though studies have suggested that the therapy is less effective when anesthesia is given.^[22] Complications from ESWT are rare and typically mild when present.^[22] Known complications of ESWT include the development of a mild hematoma or an ecchymosis, redness around the site of the procedure, or migraine.^[22]

Corticosteroid injections are sometimes used for cases of plantar fasciitis refractory to more conservative measures. The injections may be an effective modality for short-term pain relief up to one month, but studies failed to show effective pain relief after three months.^[4] Notable risks of corticosteroid injections for plantar fasciitis include plantar fascia rupture,^[3] skin infection, nerve or muscle injury, or atrophy of the plantar fat pad.^[2][10] Custom orthotic devices have been demonstrated as an effective method to reduce plantar fasciitis pain for up to 12 weeks.^[23] The long-term effectiveness of custom orthotics for plantar fasciitis pain reduction requires additional study.^[24] Orthotic devices and certain taping techniques are proposed to reduce pronation of the foot and therefore reduce load on the plantar fascia resulting in pain improvement.^[12]

Another treatment technique known as plantar iontophoresis involves applying anti-inflammatory substances such as dexamethasone or acetic acid topically to the foot and transmitting these substances through the skin with an electric current.^[10] Moderate evidence exists to support the use of night splints for 1–3 months to relieve plantar fasciitis pain that has persisted for six months.^[7] The night splints are designed to position and maintain the ankle in a neutral position thereby passively stretching the calf and plantar fascia overnight during sleep.^[7] Other treatment approaches may include supportive footwear, arch taping, and physical therapy.^[6]

Surgery

Plantar fasciotomy is often considered after conservative treatment has failed to resolve the issue after six months and is viewed as a last resort.^[2][6] Minimally invasive and endoscopic approaches to plantar fasciotomy exist but require a specialist who is familiar with certain equipment. The availability of these surgical techniques is currently limited.^[5] A 2012 study found 76% of patients who underwent endoscopic plantar fasciotomy had complete relief of their symptoms and had few complications (level IV evidence).^[4] Heel spur removal during plantar fasciotomy has not been found to improve the surgical outcome.^[25] Plantar heel pain may occur for multiple reasons and release of the lateral plantar nerve branch may be performed alongside the plantar fasciotomy in select cases.^[5][25] Possible complications of plantar fasciotomy include nerve injury, instability of the medial longitudinal arch of the foot,^[26] fracture of the calcaneus, prolonged recovery time, infection, rupture of the plantar fascia, and failure to improve the pain.^[2] Coblation surgery has recently been proposed as alternative surgical approaches for the treatment of recalcitrant plantar fasciitis.^[25]

Unproven treatments

Dry needling is being researched for treatment of plantar fasciitis

Botulinum Toxin A injections as well as similar techniques such as platelet-rich plasma injections and prolotherapy remain controversial.^{[4][7][10][27]}

Dry needling is also being researched for treatment of plantar fasciitis.^[28] A systematic review of available research found limited evidence of effectiveness for this technique.^[29] The studies were reported to be inadequate in quality and too diverse in methodology to enable reaching a firm conclusion.^[29]

Epidemiology

Plantar fasciitis is the most common type of plantar fascia injury^[9] and is the most common reason for heel pain, responsible for 80% of cases. The condition tends to occur more often in women, military recruits, older athletes, the obese, and young male athletes.^[7][11][12]

Plantar fasciitis is estimated to affect 1 in 10 people at some point during their lifetime and most commonly affects people between 40–60 years of age.^[3][4] In the United States alone, more than two million people receive treatment for plantar fasciitis.^[3] The cost of treating plantar fasciitis in the United States is estimated to be $284 million each year.^[3]

References

External links

• "Plantar fasciitis and bone spurs". American Academy of Orthopedic Surgeons.