Extract
To The Editor:I read with great interest the article, "Electrohydraulic High-Energy
Shock-Wave Treatment for Chronic Plantar Fasciitis" by Ogden et al.
(2004;86:2216-28). I congratulate them for reporting the results of the FDA
trial, which, to a vast extent, had been published earlier6,7.Some points remain open for discussion.1. The alleged efficacy of this singledose, high-energy, anesthetically
based treatment has already been discussed exhaustively by Buchbinder et
al.3 in 2002. Regarding the HealthTronics-sponsored FDA
trial2, Buchbinder et al. made the criticism that the presence of
plantar fasciitis was determined solely on clinical grounds. Also, it was
uncertain whether the two groups in the trial were comparable at baseline. In
their previous paper, Ogden et al.6 defined overall success of
treatment at twelve weeks as fulfillment of four of the following criteria:
(1) a minimum 50% improvement over baseline in the investigator's assessment
of pain (with a dolorimeter) and a score of £4 cm on a visual analogue
scale; (2) a minimum 50% improvement over baseline in the subject's
self-assessment of pain on first walking in the morning and a score of
£4 cm on a visual analogue scale; (3) a minimum 1-point or greater
improvement on a 5-point scale of distance walked without heel pain, or
maintenance of a baseline assessment of no pain or minimal pain; and (4) no
prescription of analgesics for pain in the treated heel between ten and twelve
weeks after treatment. While success according to the three criteria other
than the investigator's assessment of pain favored the active treatment, no
difference was significant (subject's selfassessment of pain: 59.7% in the
shock-wave group compared with 48.2% in the placebo group, p = 0.08; subject's
self-assessment of activity level: 71.4% in the shock-wave group compared with
67.2% in the placebo group, p = 0.49; and use of pain medications: 69.7% in
the shock-wave group compared with 67% in the placebo group, p = 0.41). I
wonder why Ogden et al., who quoted the paper by Buchbinder et al. in their
article, did not specifically respond to the objections by those authors. How
is it possible that suddenly significant differences were calculated after
three months of follow-up while, in the original FDA paper2, no
significant difference had been observed after the same duration of
follow-up?