Bone scintigraphy predicts outcome of steroid injection for plantar fasciitis

Plantar fasciitis is a common cause of foot pain and may be disabling. Although localized injection is painful, anesthetics or corticosteroids can relieve symptoms well. Bone scintigraphy can confirm the diagnosis. We hypothesized that blood-pool abnormalities could provide prognostic information on the response to such injections.

We devised scintigraphic criteria that graded the blood-pool abnormalities as being localized to the plantar enthesis, being localized to half the length of the aponeurosis, or involving the whole aponeurosis. We evaluated 24 patients with an established diagnosis of plantar fasciitis, 8 of whom had bilateral disease, leading to a total of 32 feet injected.

After injection, pain was relieved either completely or nearly completely in 20 feet. The other 12 feet had short-term or no improvement, with persistent pain and loss of function at 4-5 wk after injection. Of the 20 feet responding to injection, 14 had focal hyperemia on blood-pool images and 6 had minimal extension into the proximal third of the plantar soft tissues. No patient with diffuse hyperemia in the plantar fascia had a response (5/12 feet). On the delayed images of the 20 responders, mild inferior calcaneal uptake was seen in 8 feet, moderate uptake in 6, and severe uptake in 6. These groups did not significantly differ (P > 0.05). The blood-pool studies had good reproducibility, with a kappa-value of 0.64.

Critical evaluation of plantar blood-pool images provides prognostic information on the response to localized injection into the enthesis. Reporting such studies is simple and reproducible.