Background: Although the application of low-energy
extracorporeal shock waves to treat musculoskeletal disorders is
controversial, there has been some limited, short-term evidence
of its effectiveness for the treatment of chronic plantar fasciitis.
Methods: From 1993 to 1995, a prospective, two-tailed,
randomized, controlled, observer-blinded pilot trial was performed
to assess whether three applications of 1000 impulses of low-energy
shock waves (Group I) led to a superior clinical outcome when compared
with three applications of ten impulses of low-energy shock waves
(Group II) in patients with intractable plantar heel pain. The sample
size was 112. The main outcome measure was patient satisfaction
according to a four-step score (excellent, good, acceptable, and
poor) at six months. Secondary outcome measures were patient satisfaction
according to the four-step score at five years and the severity
of pain on manual pressure, at night, and at rest as well as the
ability to walk without pain at six months and five years.
Results: At six months, the rate of good and excellent
outcomes according to the four-step score was significantly (47%)
better (p < 0.0001) in Group I than in Group II. As assessed
on a visual analog scale, the score for pain caused by manual pressure
at six months had decreased to 19 points, from 77 points before
treatment, in Group I, whereas in Group II the ratings before treatment
and at six months were 79 and 77 points (p < 0.0001 for
the difference between groups). In Group I, twenty-five of forty-nine
patients were able to walk completely without pain at six months
compared with zero of forty-eight patients in Group II (p < 0.0001).
By five years, the difference in the rates of good and excellent
outcomes according to the four-step score was only 11% in
favor of Group I (p = 0.071) because of a high rate of
good and excellent results from subsequent surgery in Group II;
the score for pain caused by manual pressure had decreased to 9
points in Group I and to 29 points in Group II (p = 0.0006
for the difference between groups). At five years, five (13%)
of thirty-eight patients in Group I had undergone an operation of
the heel compared with twenty-three (58%) of forty patients
in Group II (p < 0.0001).
Conclusions: Three treatments with 1000 impulses
of low-energy shock waves appear to be an effective therapy for
plantar fasciitis and may help the patient to avoid surgery for
recalcitrant heel pain. In contrast, three applications of ten impulses
did not improve symptoms substantially.