Steroid injections relieve foot pain
MedWire News: Patients with plantar fasciitis experience significant short-term pain relief from a single steroid injection, confirms research published in the British Medical Journal.
Although the decrease in pain lasted for only 4 weeks, patients continued to experience a reduction in swelling for several months, say Andrew McMillan (La Trobe University, Melbourne, Victoria, Australia) and co-authors.
"These findings are important for clinical practice as they indicate that an appropriately administered dexamethasone injection is efficacious in the short term for plantar fasciitis and that such an injection may lead to beneficial longer term physiological changes to the affected plantar fascia," they write.
The researchers randomly assigned 82 patients with plantar fasciitis unrelated to systemic inflammatory disease to receive ultrasound-guided injection of the plantar fascia with dexamethasone sodium phosphate (n=42; 1 mL at 4 mg/mL) or saline (n=42; 1 mL). Treatment was preceded by ultrasound-guided posterior tibial nerve block (2% lidocaine).
Foot pain was measured using a 100-point foot health status questionnaire. Compared with baseline values, dexamethasone-treated patients had a significant 10.9-point greater decrease in this measure than controls after 4 weeks. However, pain did not significantly differ between the treatment groups at 8 and 12 weeks.
Acknowledging that the 4-week benefit did not meet the minimally important clinical change for the foot-pain measure (13-point difference), the team dichotomized the data and calculated the change that would represent a reasonable improvement from a patient's perspective.
McMilllan et al report that 2.93 patients would require treatment for one patient to experience a 19.5-point reduction in pain at 4 weeks' follow up.
In addition, ultrasound measurement of the plantar fascia thickness showed that dexamethasone-treated patients had a significantly greater reduction from baseline at 4 (-0.35 mm), 8 (-0.39 mm), and 12 weeks (-0.43 mm) compared with controls.
"The action of corticosteroids on these mechanisms is currently unclear; however, corticosteroids have been shown to inhibit fibroblast proliferation and expression of ground substance proteins," the team comments.
"It is possible that these known effects may be of benefit in the treatment of plantar fasciitis, as increased proliferation of fibroblasts and excessive secretion of proteoglycans are commonly reported features of the condition."
By Lynda Williams