Heel pain

Last evidence check March 2011

The diagnosis of plantar fascitis is usually a clinical one and investigations contribute little. They are of most use in elucidating a suspected inflammatory arthropathy or stress fracture.

Blood investigations

If an inflammatory condition is suspected a full blood count, ESR, CRP, rheumatoid screen, antibody screen and HLA serotype may be helpful. We have found these tend to be non-specific and an isotope bone scan is often more helpful. There are no publications on the value of these or other blood tests in plantar fascitis.

Imaging

heel spur xray

A "heel spur" - a shelf not a spur, and not the cause of heel pain

A standing lateral hindfoot view will show calcaneal pathology including stress fractures, erosions at the plantar fascial attachments, subtalar arthritis and calcaneal spurs. An oblique view has been suggested to show stress fractures and erosive changes. An isotope bone scan may show increased uptake at the medial calcaneal tubercle: the sensitivity is about 60% and specificity 100% (Williams et al 1987, Ozdemir 2002). Both ultrasound and MR scanning show plantar fascia thickening, perifascial oedema and areas of disruption. (Gibbon and Long 1999, Yu 2000, Kane 2001).

Plantar calcaneal spurs are seen in 60-90% of patients with plantar fascitis and 10-30% of the normal population. Therefore, as there are many more people without plantar fascitis than with, the vast majority of spurs are asymptomatic. Contrary to common belief, the "spur" is actually a shelf of bone seen end on and lies in the attachment of flexor digitorum brevis rather than the plantar fascia. As spurs may be asymptomatic and removal of the spur seems no better than plantar fascial release alone in surgically treated patients, the spur should probably be seen as a marker of plantar fascitis but not the cause of symptoms.

Both ultrasonography and MRI show thickening of the plantar fascia in symptomatic patients. Tibialis posterior tendonopathy occasionally co-exists with plantar fasciitis and can be shown by either of these modalities.

Few studies of imaging consider the impact of the results of imaging investigations on the diagnostic process, treatment plan or prognosis. Williams et al found that 55% of patients with plantar fascitis and increased uptake on isotope scanning had persistent symptoms requiring injection compared to 28% of those without increased uptake. However, those with increased uptake were more likely to respond to injection than those without increase (76% versus 16%). Their diagnostic criteria and treatment protocol may not have been standardised so it is difficult to draw conclusions. Frater et al (2006) found that a response to injection was associated with focal rather than diffuse uptake on the blood-pool images of an isotope scan. However, it is unlikely that a clinician would perform an expensive test involving radiation dosage to predict the need for, or response to, an injection.

Routine Xrays of patients with plantar fascitis are not worthwhile. Levy et al (2006) found abnormalities that infulenced management in only 4/215 patients with plantar heel pain.

Imaging is probably only of value in elucidating clinically borderline cases or identifying a systemic inflammatory condition. We usually use isotope bone scanning for both indications although are increasingly using as sufficient expertise becomes available locally.

Other investigations

Nerve conduction testing may occasionally be useful in suspected tarsal tunnel syndrome or the "heel pain triad" of plantar fasciitis, tibialis posterior tendonopathy and tarsal tunnel syndrome.