Approach

Diagnosis is usually based on a thorough history and physical examination.[3]​ There is no laboratory test that can confirm or rule out the diagnosis.

Clinical history

Plantar fasciitis typically presents with heel pain that is stabbing or knife-like in character. The most common location of pain is the anteromedial aspect of the heel. Symptoms can extend along the course of the plantar fascia into the central arch. Pain may also radiate to the lateral heel.[3]​ To make the diagnosis of plantar fasciitis, the pain must be relieved with rest. The pain typically occurs when taking the first few steps in the morning and when rising from a sitting position (poststatic dyskinesia) and generally improves with ambulation and mobilization. However, during standing and other activities of daily living, a progressive worsening of symptoms often occurs, with increased complaints of pain at the end of the day.[3]​ Pain is worse with barefoot walking, particularly on hard floors, and is better with nonsteroidal anti-inflammatory drug use. There is unlikely to be a history of injury to the heel.

It is a bilateral complaint in about one third of patients, although people with bilateral pain are more likely to have a systemic cause for their pain.[4][5][6]

Although a bothersome condition, pain is self-limiting and usually resolves between 6 and 18 months without treatment.[2]

Identification of risk factors

Associated risk factors include running, BMI >25 kg/m², presence of equinus, patient age between 40 and 60 years, sedentary lifestyle, presence of pes planus or pes cavus, a history of increase or change in physical activity, and occupations or activities which involve prolonged standing or walking.

Physical examination

On examination of the foot, there is focal, pinpoint tenderness on palpation of the plantar medial calcaneum or the plantar central calcaneum. In addition, tenderness occurs in the proximal third of the plantar fascia.

Generally, minimal clinical signs of inflammation such as swelling and erythema will be present. Pain with midfoot, hindfoot, and ankle range of motion is generally absent.[3]

The lateral squeeze test is performed to rule out stress fracture; a positive result occurs when pain on lateral compression of the heel is greater than inferior heel pain, and is suggestive of stress fracture.[4][22]​ Inverting the heel may identify nerve involvement. Both the dorsiflexion-eversion test (pain with dorsiflexion of the ankle joint and eversion of the subtalar joint) and the Windlass test (pain with metatarsophalangeal joint extension) are usually positive with plantar fasciitis.[23][24]​​

Tenderness along the medial rearfoot, rather than along the fascia itself, may suggest flexor hallucis longus tendon pathology.[24]

Palpation or percussion along the superior margin of the calcaneus may elicit Tinel sign (paresthesia on percussion of the tibial nerve or its branches) in the presence of nerve entrapment, tarsal tunnel, or neuritis.[25] This sign is usually negative in people with plantar fasciitis, although it may be positive in people with concomitant conditions.

Radiographs

Plain film x-rays of the foot are of little benefit in typical cases of plantar fasciitis, although they may be helpful in ruling out other pathology. X-rays are ordered initially if there is suspicion of a stress fracture or alternative cause of heel pain, or if there is a history of trauma.[3]​ Otherwise, x-rays are ordered subsequently if the patient does not improve with standard therapy.[26] Radiographs may show infracalcaneal spurring but this is not needed for diagnosis and is more likely an incidental finding.[12][27] The presence of a calcaneal spur does not generally alter the treatment course.[3]​​

Subsequent investigations

Further investigations may be helpful in patients in whom conservative treatment has failed and where an alternative diagnosis is being considered. Laboratory testing for rheumatoid factor and anticyclic citrullinated peptide antibody is recommended when there are clinical or radiographic signs suggesting rheumatoid arthritis. Laboratory testing for HLA-B27 is recommended if there is any suspicion of a spondyloarthropathy (e.g., axial spondyloarthritis, reactive arthritis).[6]

Technetium bone scanning may be ordered if radiographs are inconclusive for stress fractures or if the patient does not respond to conservative treatment. With plantar fasciitis, this scan demonstrates focal increased uptake in blood pool images corresponding to the plantar fascial insertion.[28]

MRI is recommended in cases of recalcitrant heel pain (pain for more than 12 months) or if there are any soft tissue or osseous masses palpated or visualized on other imaging studies.

Ultrasound may be used in place of MRI for the same indications.[29]​ Ultrasound scanning demonstrates thickening of the plantar fascia of 4 mm or more in people with plantar fasciitis.[30] Ultrasound investigation has also been able to reveal enthesopathy and hypoechogenicity.

Referral

Referral to an orthopedic or rheumatology specialist is recommended if any radiographic abnormality requiring specialist input reveals itself.

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