Clinical Question: Is shock wave therapy effective in treating chronic plantar fasciitis?

Setting: Outpatient (specialty)

Study Design: Randomized controlled trial (single-blinded)

Synopsis: Recreational athletes who ran more than 30 miles per week and experienced heel pain that lasted more than 12 months were randomly assigned (masked allocation) to receive extracorporeal shock wave therapy (ESWT; n = 22) or sham shock wave therapy (n = 23). ESWT consisted of a total of 6,300 shocks in three weekly treatment sessions using an energy flux density of 0.16 mJ per mm² and a frequency of 4 Hz. The sham therapy used a special sound-reflecting pad but was otherwise the same. The physician administering the treatment was unblinded, but a masked assessor determined the outcomes six and 12 months after patients completed the treatment. The main outcome measure was pain on walking using a 10-point scale.

Of the patients assigned to ESWT, three dropped out because the therapy was ineffective, and three were lost to follow-up. Among the patients receiving sham therapy, three dropped out because the therapy was ineffective, and one was lost to follow-up. The baseline pain ratings were the same in each group. The patients treated with ESWT improved from a score of 6.9 at baseline to 2.1 at six months and 1.5 at 12 months. The scores of the patients receiving sham therapy improved from 7.0 at baseline to 4.7 and 4.4 at six and 12 months, respectively. Additionally, among patients treated with ESWT, 12 of the 20 persons and 13 of the 18 persons evaluated at six and 12 months, respectively, experienced at least a 50 percent decrease in pain, compared with only six of the 22 and seven of the 20 control patients at six and 12 months.

Although the study includes the patients who dropped out because of lack of benefit, it does not include the patients who were lost in the analysis. If one used a worst-case analysis and assumed that persons treated with ESWT who were lost had no benefit and those treated with sham ultrasonograpy improved, the numbers are still good for ESWT (number needed to treat = four).

Bottom Line: A recent Cochrane review found limited evidence that ESWT was effective in treating plantar fasciitis, while another article (Buchbinder R, et al. Ultrasound-guided extracorporeal shock wave therapy for plantar fasciitis: a randomized controlled trial. JAMA September 18, 2002;288:1364–72.) found it ineffective for acute relief. In this study, lower doses of energy were effective in reducing symptoms in patients with chronic plantar fasciitis after six months. It is curious that the authors did not report on immediate symptom relief. (Level of Evidence: 2b)

Used with permission from Barry H. ESWT effective in chronic plantar fasciitis. Retrieved April 21, 2003, from: http://www.InfoPOEMs.com.