Diagnosing and managing plantar fasciitis
Rheumatologist Dr Tim Jenkinson offers advice on detecting and treating the commonest cause of heel pain
The commonest cause of heel pain is plantar fasciitis. Other causes include fat pad contusion (fat pad syndrome), calcaneal stress fractures, tarsal tunnel syndrome and medial calcaneal nerve entrapment.
The differential diagnosis of foot pain is made easier by dividing the foot into anatomical areas.
Differentiating causes of rearfoot and midfoot pain
Rearfoot pain: lPlantar fasciitis lFat pad syndrome lCalcaneal fracture (stress, trauma) lTarsal tunnel syndrome lMedial calcaneal nerve entrapment lTarsal stress fracture lSpondyloarthropathy lOsteoid osteoma
Midfoot pain: lTibialis posterior tendinopathy lNavicular stress fracture lExtensor tendinopathy lMidtarsal joint strain
The history of plantar fasciitisis is usually typical of an enthesopathy; the enthesis is the attachment of a ligament or tendon to bone. The pain of plantar fasciitis is of gradual onset and is typically worse in the morning, often making it difficult to weight bear fully for several minutes. The discomfort slowly improves with exercise but often returns after periods of rest. Many patients experience a dull aching pain in the heel throughout the day. The pain is initially well localised to the medial heel but may radiate distally to the mid- and forefoot. Pain is rarely referred proximally to the Achilles tendon.
Most patients do not give a history of trauma. There may be a history of altered activity with changes in frequency, duration or intensity of exercise.
It is essential to ask about possible underlying rheumatological conditions including the seronegative spondylarthropathies (psoriatic, reactive, enteropathic and ankylosing spondylitis). These conditions are often complicated by the development of an enthesopathy. Plantar fasciitis is often bilateral when associated with a seronegative arthropathy.
Patients with plantar fasciitis have well localised tenderness over the inferio-medial aspect of the calcaneus. Dorsiflexion of the metatarsophalangeal joints and, in particular, the big toe stretches the plantar fascia and reproduces the pain. Occasionally the tenderness may extend distally along the plantar fascia, causing midfoot pain. Examination must include assessment of the ankle joint, subtalar joint and midfoot. A biomechanical assessment is required to detect abnormalities associated with plantar fasciitis including excessive pronation (flattened arch) and supination (high rigid arch) of the foot.
Examination of running shoes can reveal abnormal patterns of wear, indicating abnormal gait. Examination should include the posterior heel including Achilles tendon. Tapping the medial and lateral calcaneum over the medial calcaneal and lateral plantar nerves may provoke pain and sensory disturbance, indicating nerve entrapment (Tinel's sign). General examination should include assessment for possible seronegative arthropathies.
Routine radiographs are not required unless there is a history of trauma. The demonstration of a heel spur does not affect the management of plantar fasciitis. Consider radiographs in children and the elderly who have a lower incidence of plantar fasciitis. Calcaneal stress fractures are not always evident on plain radiographs.
Musculoskeletal ultrasound is useful to confirm the diagnosis in chronic cases unresponsive to normal treatment. In plantar fasciitis the proximal fascia is thickened (>4mm) and hypoechoic. MRI is reserved for recalcitrant pain or atypical presentations.
Most cases of plantar fasciitis will resolve over six months, irrespective of treatment decisions.
Rest or a significant reduction in exercise will reduce symptoms. Analgesics or NSAIDs, alone or in combination, provide further symptomatic relief. Heel supports can improve symptoms but a custom-made orthotic is only required in recalcitrant cases or if there are associated biomechanical abnormalities.
Physiotherapy is probably helpful although the evidence base is limited. It includes passive and active stretching of the plantar aponeurosis, intrinsic foot muscle exercises to support the longitudinal arch and strategies to improve the flexibility of gastrocnemius and soleus.
Taping is also employed to support the longitudinal arch and offload the plantar aponeurosis. Night resting splints maintain the foot in dorsiflexion, permitting healing of the plantar fascia in full extension. There is some evidence that this approach is helpful.
Corticosteroid injections are often used to treat plantar faciitis. This approach is certainly effective in the short-term but there is limited evidence of long-term efficacy. A poor response may indicate that the injection has been inaccurately placed and subsequent injections can be performed under ultrasound guidance. There may be a small risk of rupture of the plantar aponeurosis associated with corticosteroid injection.
Patients with chronic unremitting plantar fasciitis may benefit from a short leg walking cast. Surgery is only considered for resistant cases where all other treatments have failed. Plantar fasciotomy provides initial relief of symptoms but, again, the benefit is not sustained in the long-term. Patients may develop problems in the midfoot and forefoot following surgery as a result of longitudinal arch instability.
Plantar fasciitis is the most common cause of heel pain. It is often the result of overuse and occasionally caused by trauma or an underlying rheumatological disease. Diagnosis is based on history and clinical examination. Investigation of a typical case is unnecessary.
The majority of cases resolve with standard therapy within six months. Resistant cases require a review of the underlying diagnosis and consideration of secondary causes. Surgery is rarely necessary.
Anatomy of plantar fascia
The plantar fascia consists of a central aponeurosis and thinner medial and lateral components.
The plantar fascia, plantar calcaneonavicular ligament and interosseous ligaments combine with the tibialis posterior, tibialis anterior, flexor hallucis longus and flexor digitorum to provide support for the medial arch of the foot.
When the toes are extended, the plantar fascia is pulled around the metatarsal heads and this shortens the plantar fascia, raises the longitudinal arch and supinates the foot.
Flexion of the toes relaxes the plantar fascia, facilitating pronation and flexibility of the foot.
These changes in flexibility are passive, improving the efficiency and function
of gait (see diagram left).
Tim Jenkinson is consultant in rheumatology, sports and exercise medicine, Royal National Hospital for Rheumatic Diseases, Bath