Letters to the Editor. Effectiveness of Extracorporeal Shockwave Treatment in 353 Patients with Chronic Plantar Fasciitis

To the Editor:

Upon receiving my copy of the November/December 2005 issue of the Journal, I had great hope and anticipation in reading and evaluating the findings of the lead article about the effectiveness of extracorporeal shockwave treatment (ESWT) (“Effectiveness of Extracorporeal Shockwave Treatment in 353 Patients with Chronic Plantar Fasciitis” by Donald M. Norris, MD, Kimberly M. Eickmeier, DPM, and Bruce R. Werber, DPM). As our profession continues to advocate the medical justification for and fair third-party reimbursement of this modality, we find ourselves continually trying to negate the findings of the Buchbinder et al[1] study that proved to be such a fatal blow to this treatment regimen. Although providers, both podiatric physicians and our orthopedic colleagues, have continued to criticize and point out the problems with that study, and justifiably so, we have not been able to reverse the negative impact it had on ESWT.

The recent article by Norris et al, which attempts to support ESWT in the treatment of plantar fasciitis, is just one more unsuccessful attempt to bring ESWT back to life. Because this is such a controversial treatment, the need for good studies to substantiate this modality is pressing. Unfortunately, this study does not meet that urgent need. That the authors would choose to use a posttreatment survey instrument in the manner in which they did is disturbing. This study merely points to its own weaknesses: a weak study design with no comparison group, no randomization of patients, no control of confounders, and the use of an instrument that has never been previously used or validated. What I find most disturbing about this study is its “recall bias”: pretreatment pain levels were estimated at a posttreatment date, and then these levels were compared with posttreatment pain levels, and somehow the authors arrived at statistical validity!

In addition, the authors conclude that the treatment would result in “decreased costs” when no cost analysis was done, then stating that this finding is “merely speculation.”

The use of a questionnaire survey tool is troubling enough. When such a tool is used in the manner demonstrated in this study—ie, after the fact—the result is not exactly what I would call a study meeting the standards of evidence-based medicine.