Back in 2009, the Journal of the American Podiatric Medical Association (JAPMA) published this impressively titled study: Extracorporeal Shockwave Therapy for Interdigital Neuroma: A Randomized, Placebo-Controlled, Double-Blind Trial that found:
The treatment group showed a significant difference before and after extracorporeal shockwave therapy (P < .0001). The sham group did not have a significant difference after 12 weeks (P = .1218).
and as such concluded
Conclusions: Extracorporeal shockwave therapy is a possible alternative to surgical excision for Morton’s neuroma
Given that impressively sounding title and the p values you could not help but be impressed, except that the way the results are stated in that quote above should have let off a huge alarm bell that the JAPMA editorial and peer review process had failed. The whole point of having a control group is that you do a statistical test comparing the outcomes between the intervention and control groups (ie a between groups analysis). What this study did was a within groups analysis which is not how you analyse a trial comparing two (or more) groups.
The study actually posted all the raw data in table, so I reanalyzed their data using the right analysis and published that as a letter to the editor of JAPMA. Others (here and here) also expressed the concerns about how the study was analysed. It turns out that the authors own data actually showed that shock wave therapy did not work for mortons neuroma!
JAPMA did not do the right ethical thing and retract the publication. They should have. They did not even link the abstract or paper on the website to the letters-to-the editor pointing out about the wrong analysis. They should have. If you read that paper and do not know about the issues of between groups vs within groups analysis, then without going quite a way out of your way to find the letters-to-the editor, you would believe that shock wave works for mortons neuroma. That is a problem.
