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Radial Extracorporeal Shock Wave Therapy
Is Safe and Effective in the Treatment of
Chronic Recalcitrant Plantar Fasciitis
Results of a Confirmatory Randomized Placebo-Controlled
Multicenter Study
Ludger Gerdesmeyer,*†‡ MD, PhD, Carol Frey,§MD, Johannes Vester,|| PhD,
Markus Maier,¶PhD, Lowell Weil Jr,#DPM, Lowell Weil Sr,#DPM, Martin Russlies,** PhD,
John Stienstra,†† DPM, Barry Scurran,†† DPM, Keith Fedder,§ MD, Peter Diehl,‡‡ MD,
Heinz Lohrer,§§ MD, Mark Henne,† MD, and Hans Gollwitzer,†MD
From the †Department of Orthopedic and Traumatology, Technical University Munich, Klinikum
Rechts der Isar, Germany, the ‡Department of Joint Arthroplasty and Clinical Science, Mare
Clinic, Kiel, Germany, §Orthopaedic Foot and Ankle Center, Manhattan Beach, California, ||IDV
Data Analyses and Study Planning, Biometrics in Medicine, Gauting, Germany, the ¶Department
of Orthopedics, Ludwig Maximilian University, Munich, Germany, the #Weil Foot and Ankle
Institute, Des Plaines, Illinois, **University Schleswig Holstein, Campus Lübeck, Lübeck,
Germany, the ††Department of Podiatry, The Permanente Medical Group Inc, Union City,
California, the ‡‡Department of Orthopedics, University Rostock, Rostock, Germany, and the
§§Institute of Sportsmedicine, Frankfurt am Main, Germany
Background: Radial extracorporeal shock wave therapy is an effective treatment for chronic plantar fasciitis that can be admin-
istered to outpatients without anesthesia but has not yet been evaluated in controlled trials.
Hypothesis: There is no difference in effectiveness between radial extracorporeal shock wave therapy and placebo in the treat-
ment of chronic plantar fasciitis.
Study Design: Randomized, controlled trial; Level of evidence, 1.
Methods: Three interventions of radial extracorporeal shock wave therapy (0.16 mJ/mm2; 2000 impulses) compared with
placebo were studied in 245 patients with chronic plantar fasciitis. Primary endpoints were changes in visual analog scale com-
posite score from baseline to 12 weeks’ follow-up, overall success rates, and success rates of the single visual analog scale
scores (heel pain at first steps in the morning, during daily activities, during standardized pressure force). Secondary endpoints
were single changes in visual analog scale scores, success rates, Roles and Maudsley score, SF-36, and patients’ and investi-
gators’ global judgment of effectiveness 12 weeks and 12 months after extracorporeal shock wave therapy.
Results: Radial extracorporeal shock wave therapy proved significantly superior to placebo with a reduction of the visual ana-
log scale composite score of 72.1% compared with 44.7% (P=.0220), and an overall success rate of 61.0% compared with
42.2% in the placebo group (P=.0020) at 12 weeks. Superiority was even more pronounced at 12 months, and all secondary
outcome measures supported radial extracorporeal shock wave therapy to be significantly superior to placebo (P<.025, 1-
sided). No relevant side effects were observed.
Conclusion: Radial extracorporeal shock wave therapy significantly improves pain, function, and quality of life compared with
placebo in patients with recalcitrant plantar fasciitis.
Keywords: heel pain; plantar fasciitis; shock wave; lithotripsy; radial extracorporeal shock wave therapy
1
The American Journal of Sports Medicine, Vol. X, No. X
DOI: 10.1177/0363546508324176
© 2008 American Orthopaedic Society for Sports Medicine
AJSM PreView, published on October 1, 2008 as doi:10.1177/0363546508324176
2Gerdesmeyer et al The American Journal of Sports Medicine
Plantar fasciitis is the most common cause of heel pain and
accounts for approximately 11% to 15% of all foot symp-
toms requiring professional care in the adult.1,4,28 The
course of the disease is typically self-limiting, and about
90% of patients are successfully treated with nonsurgical
measures.1,2,4 The self-limiting character of the disease
also explains the relatively high success rates observed in
the placebo arm of double-blind, randomized, controlled
trials.1,2,4,8,25,28,38 Nevertheless, the remaining patients
enter a state of recalcitrant painful heel syndrome, often
requiring operative intervention.1,2,4,8 Thereby, operative
treatments like fasciotomy have shown promising results
but are often associated with long recovery times, and ath-
letes especially seek alternative treatment modalities that
allow for continued training.1,2,4,8
Extracorporeal shock wave therapy (ESWT) has been
introduced for the treatment of recalcitrant painful heel syn-
drome as an alternative to surgery, allowing fast recovery
times without the necessity of reduced weightbearing or
immobilization.22,23,28,33,38 However, randomized, controlled
trials assessing ESWT in chronic painful heel syndrome
have revealed contradictory results, and the clinical effec-
tiveness has been discussed controversially.3-5,8,14,17,18,23,32 By
reviewing the published trials it becomes obvious that the
different treatment parameters of ESWT are of utmost
importance for the outcome of treatment.5,17,22,23,28 In this
respect, especially the application of local anesthesia has
been shown to reduce efficacy.19,30 Furthermore, higher ener-
gies have been associated with greater pain reduction.23,27,33
It becomes apparent that pooling data of different treatment
protocols in meta-analyses or systematic reviews is criti-
cal.22,28,35 Therefore, in assessing the effectiveness of ESWT
in plantar fasciitis, only specific treatment protocols should
be evaluated, and results could not be generalized.
Radial ESWT (rESWT) has been introduced into medicine
as an effective and easy method to apply shock wave tech-
nology.15,20 It represents an alternative to focused shock wave
treatment, allowing for a broader application. Radial shock
waves are generated ballistically by accelerating a bullet to
hit an applicator, which transforms the kinetic energy into
radially expanding shock waves.15,20 Compared with these
radial shock waves, the focused shock waves show deeper tis-
sue penetration with significantly higher energies concen-
trated to a smaller focus.15,16,20,22,28 This article reports on a
randomized, controlled, and double-blinded Food and Drug
Administration (FDA) study evaluating the efficacy and
safety of rESWT in patients with chronic painful heel
syndrome.
METHODS
Study Design and Follow-up
This double-blind, randomized, placebo-controlled trial with
parallel group design was conducted internationally at 3
study centers in the United States and 5 study centers in
Europe. Patient enrollment took place during an 11-month
period. A total of 254 patients were randomly assigned to
receive either rESWT or placebo treatment with concealed
allocation in permuted blocks of 4 to 8, stratified by treatment
center with the use of a computer-generated random list
(Rancode; idv Data Analysis and Study Planning, Gauting,
Germany). Concealment of randomization was guaranteed by
nontransparent envelopes. Both patients and assessing
physicians were blinded to randomization as well as to the
evaluating physician. The trial was conducted as an FDA
approval study. In designing the study, the authors adhered to
the standardized guidelines of good clinical practice from the
International Conference on Harmonization (ICH).11,12
After 3 shock wave or placebo interventions were
applied, patients were followed until the end of the fol-
low-up 1 period (12 weeks after the last intervention). At
this visit, the participants’ response to treatment was
rated, and patients who showed sufficient response on a
clinically relevant level continued the follow-up 2 phase,
which ended 12 months after the last rESWT or placebo
intervention. If patients suffered from significant pain
after intervention, deblinding on demand after 12 weeks
was allowed to provide other treatment options outside
the trial instead of suffering for 12 months. These
patients left the trial with the worst outcome, which was
carried forward. All these “worst” data were carried for-
ward and used for analysis.
Participants
Patients were recruited from the participating study sites
and from community-based referring physicians (primary
care physicians, podiatrists, orthopaedic surgeons).
Participants of all activity levels were included and were
asked to continue on the same activity level throughout
the study, although activity level at enrollment and during
the study were not specifically assessed. The study was
approved by the FDA and the responsible independent
institutional review boards. Written informed consent was
obtained from all participants. A total of 495 patients with
plantar heel pain were screened; 254 patients met enroll-
ment criteria and were enrolled in the study. A total of 251
patients out of 254 were treated. The flow of participants
through the study is displayed in Figure 1.
Inclusion Criteria
The complete inclusion criteria are listed in Appendix A
(available online at http://ajs.sagepub.com/supplemental/).
Inclusion criteria included a history of at least 6 months of
chronic plantar painful heel syndrome that proved resist-
ant to nonsurgical treatment. Diagnosis was confirmed
clinically by physical examination with a typical point of
*Address correspondence to Ludger Gerdesmeyer, MD, PhD, Department of Joint Arthroplasty and Clinical Science, Mare Clinic, Eckernförder Strasse 219, D-
24119 Kiel-Kronshagen (e-mail: Gerdesmeyer@aol.com).
One or more authors has declared a potential conflict of interest. Lowell Weil Jr and Lowell Weil Sr received research funding for this study from
Electro Medical Systems. Markus Maier is a clinical consultant for Electro Medical Systems. Heinz Lohrer has received funding for research from
Electro Medical Systems. The study was funded by Electro Medical Systems.
Vol. X, No. X, XXXX Efficacy of rESWT in Chronic Recalcitrant Plantar Fasciitis 3
Figure 1. Flow of participants through the study.
aSafety population: all patients receiving at least one treatment session.
bITT population, intent-to-treat. All patients who had at least one treatment session and also at least one evaluation after the first treatment without severe
deviation of entry criteria “full analysis set,” according to ICH E9 Biostatistics.11,12
cPP population, per protocol. Exclusion of patients from ITT population with protocol violations (inclusion/exclusion criteria, incomplete study treatment,
premature discontinuation).
dSufficient response was considered at least a 60% reduction in pain on 2 of the 3 VAS scales (overall success VAS), or if less pain reduction, then the
patient had to be able to work and complete activities of daily living, had to be satisfied with the outcome of the treatment, and must not have required
any other treatment to control heel pain. Participants were requested to continue until follow-up 2 (12 months).
eData reflects last value carried forward (LVCF) replacement of missing values of “nonresponders” in the ITT population.
4Gerdesmeyer et al The American Journal of Sports Medicine
maximum tenderness over the medial tubercle of the cal-
caneus.1,4 To be eligible, participants had to score signifi-
cant pain of at least 5 or greater on all 3 visual analog scale
(VAS) scores (with a maximum of 10), must have had sig-
nificant limitation on the Roles and Maudsley Score (fair
or poor), and had to have failed results from at least 2 non-
pharmacological and 2 pharmacological treatments. All
patients had to respect a sufficient washout period after
each intervention prior to enrollment. The specific washout
phases were determined as at least 6 weeks from last cor-
ticosteroid injection; 4 weeks from the last local anesthetic
injection, iontophoresis, ultrasound, and electrotherapy; 1
week from the last intake of nonsteroidal antiinflamma-
tory drugs (NSAIDs); and 2 days from last heat, ice, mas-
sage, stretching, or modification of night splinting and
orthotics.
Exclusion Criteria
Reasons for exclusion are listed in the Appendix B (avail-
able online at http://ajs.sagepub.com/supplemental/).Major
reasons for exclusion were rheumatic or other systemic
inflammatory disease, osteomyelitis, active infection or his-
tory of chronic infection in the treatment area, neurological or
vascular insufficiencies, nerve entrapment syndrome, distur-
bance of coagulation or ongoing anticoagulatory therapy, sig-
nificant bilateral heel pain in need of medical treatment, and
pregnancy.
Study Procedures
Randomization and treatment were started within 28 days
after screening. Radial ESWT or identical placebo were
administered in 3 sessions, each 2 weeks (±4 days) apart.A
total of 2000 shock waves of the assigned intervention
were delivered per session with the Swiss Doloclast radial
shock wave device (EMS Electro Medical Systems, Nyon,
Switzerland). Before the intervention, the point of maxi-
mum tenderness was clinically located by the treating cli-
nician, and the hand-piece was coupled to the identified
area by using specific ultrasound coupling gel (EMS
Electro Medical Systems).
In the treatment group, 2000 impulses of radial shock
waves with an energy flux density of 0.16 mJ/mm2and a
rate of 8 impulses per second were applied at each treat-
ment session. Patients in the control group received iden-
tical placebo intervention with a placebo hand-piece that
prevented transmission of shock waves. The placebo hand-
piece was identical in design, shape, and weight to ensure
that there was no way to identify the placebo hand-piece.
The treatment in the placebo group was the same com-
pared with the active one. Thereby, set up and sound created
by the shock wave device was identical in both groups; how-
ever, no energy was administered in the placebo group.
The intervention was performed in the office by the non-
blinded orthopaedic surgeon or podiatrist, locating the
tip of the applicator to the most tender point at the
medial calcaneal tubercle, controlling proper placement by
patient-controlled feedback, and adjusted during treat-
ment if necessary.
A standardized rescue medication was allowed through-
out the entire study if pain became unbearable (2 g of acet-
aminophen per day for up to 14 days after the last
intervention; thereafter, 2 g of acetaminophen per week).
No other therapies were allowed, and orthotics could not
be modified until the 12-week follow-up (follow-up 1).
Outcome Measures
The primary outcome measure was overall heel pain
reduction measured by the percentage change of the VAS
composite score 12 weeks after treatment compared with
baseline, with last value carried forward (LVCF) replace-
ment of missing values with the last recorded value and
correction for interfering analgesic therapy. The 12-month
analysis was performed in the same manner by replacing
missing values in LVCF and correction for interfering
analgesic therapies with the last recorded value. The
heel pain composite score was defined as the sum of three
10-cm VAS scores: heel pain when taking the first steps in
the morning, heel pain while doing daily activities, and
heel pain while applying a standardized local pressure
with the Dolormeter (EMS Electro Medical Systems) to
quantify local pressure pain. The Dolormeter is a device
that allows for objectivity of pressure application, with an
integrated scale to exactly determine the applied local
pressure.17 The blinded investigator used the Dolormeter
to measure pressure sensitivity at the point of maximum
tenderness. The pressure level measured at the
Dolormeter scale that just elicited unbearable pain was
documented as baseline value and was quantified by the
Dolormeter on the 10-cm VAS scale. At each follow-up visit,
the same Dolormeter pressure was applied, and the subject
was asked to score the pain on the VAS. The increased
pressure pain tolerance reflects the shock wave–induced
effect.
The further primary efficacy criteria were the single suc-
cess rates and the overall success rate with regard to heel
pain, defined as percentage decrease of heel pain larger
than 60% from baseline at 12 weeks after treatment for at
least 2 of the 3 heel pain (VAS) measurements. To keep the
multiple level of α, the further set of primary efficacy cri-
teria were tested in the a priori–ordered sequence accord-
ing to the principle of a priori–ordered hypotheses.25
The primary endpoint for comparison of groups was 12
weeks after the last treatment. At this point the decision
was also made whether the patient had sufficient treat-
ment response to continue the study. Sufficient response
was considered a minimum 60% reduction in pain on 2 of
3 VAS scores. Patients who showed sufficient and clinically
relevant response to rESWT were to continue in the follow-
up 2 period (12 months after last rESWT). Patients who
suffered from significant pain after intervention deblind-
ing on demand after 12 weeks were allowed to explore
other treatment options outside the trial instead of suffer-
ing for 12 months. These patients left the trial with the
worst outcome, the data of which were carried forward and
used for analysis.
Secondary outcome measures were changes in Roles and
Maudsley score, SF-36 physical percent changes, SF-36
Vol. X, No. X, XXXX Efficacy of rESWT in Chronic Recalcitrant Plantar Fasciitis 5
mental percent changes, investigator’s judgment of effec-
tiveness (7-point scale), patient’s judgment of therapy sat-
isfaction (7-point scale), and patient recommendation of
therapy to a friend (all at 12 weeks after treatment).
Furthermore, VAS composite score, success rates, and sin-
gle VAS scores were assessed after completion of follow-up
2 (12 months after last treatment session).
Safety Criteria
All patients who had at least one treatment session were
analyzed for safety. Patients were followed throughout the
study, and all local tissue effects and adverse events were
recorded. Additionally, the investigator’s global judgment
of tolerability was assessed on a 7-point rating scale 12
weeks after the last treatment. To assess local adverse
event tendon rupture observation, Semmes-Weinstein
5.07 (10 g) Monofilament Assessment, Toe Clawing
Observation, and Ankle-Brachial Assessment of the lower
extremity were performed at each visit. All assessments
but one were done by clinical examination. The Semmes-
Weinstein Monofilament was used to assess global neuro-
logical deficiencies. A 10-gram (5.07 log) monofilament
wire was applied to each foot at 10 sites. Loss of protective
sensation generally is indicated by a patient’s inability to
feel the monofilament at 4 or more of the 10 sites.
Statistical Analysis
The study had a statistical power of 90% to detect a reduc-
tion by 50 percentage points in the primary outcome meas-
ure of a reduction of VAS composite score from baseline to
12 weeks after completion of shock wave treatment. A
dropout rate of 10% was calculated as well before study
start.
To keep the multiple level of α, the set of primary effi-
cacy criteria were tested in the a priori–ordered sequence
according to Maurer.25 By this, if the first test is statisti-
cally significant (VAS composite score), the second test
(overall success rate) can be performed to confirm with full
level of α. If the second test (overall success rate) is also
statistically significant, the single success rates can be
tested to confirm with full αin the sequence “heel pain
when taking first steps of the day,” “heel pain while doing
daily activities,” “heel pain after application of the
Dolormeter” as long as the preceding test is statistically
significant. Efficacy of the rESWT treatment is proved if at
least the first hypothesis (VAS composite score) shows a
statistically significant result. A value of P<.025 (1-sided)
was considered statistically significant.
To identify differences in effect size between the differ-
ent intervention groups, the Mann-Whitney effect size
with predefined benchmarks was used to define the proba-
bility that a randomly selected participant from the
rESWT group was better off than a randomly selected par-
ticipant from the control group. In accordance with Colditz
et al,6the authors used relevant benchmarks that corre-
sponded to a Mann-Whitney effect size of 0.5 for equality
(active therapy no better or worse than placebo); 0.44 or
0.56 for small-sized inferiority or superiority, respectively;
0.36 or 0.64 for medium-sized (clinically significant) inferi-
ority or superiority, respectively; and 0.29 or 0.71 for large-
sized inferiority or superiority, respectively. Furthermore,
in accordance with the recommendations of the ICH E9
Biostatistics Guideline,11,12 statistical analyses were per-
formed by an independent institute, idv-Data Analysis and
Study Planning, Gauting, Germany, using its Report,
Testimate, and AE-Base software programs.
RESULTS
Enrollment and Treatment
A total of 254 patients with chronic painful heel syndrome
were enrolled, with 252 randomly assigned to rESWT (n =
129) or identical placebo rESWT (n =122). Three of the 254
enrolled patients did not receive any study treatment due
to recovery before treatment start (2 patients before and 1
patient immediately after randomization). The flow of par-
ticipants through the study is displayed in Figure 1. The 2
groups showed identical parameters with respect to demo-
graphic characteristics, intensity and duration of heel pain
(Table 1), physical and mental health, and previous non-
pharmacological and pharmacological therapies. The
required number of pulses and energy level for treatment
was reached in all cases without any anesthesia.
Major Outcomes
The primary endpoint “changes in VAS composite score at
12 weeks compared with baseline” could be assessed in
89.6% of the patients (Figure 1). All patients providing
postbaseline data were included in the analysis of the
intent-to-treat (ITT) population with LVCF replacement of
missing values and score correction with regard to inter-
fering concomitant analgesic therapy (according to prede-
fined criteria; see Appendix C, available online at
http://ajs.sagepub.com/supplemental/).
The primary outcome measures are summarized in
Table 2 in the order of a priori testing. Hence, efficacy of
rESWT compared with placebo was confirmed for the com-
posite score of heel pain (VAS) (P=.0103, 1-sided) using
the continuous VAS scores as well as for the overall success
rate (P=.0014, 1-sided), defining a >60% pain decrease in
at least 2 of 3 heel pain measurements as therapeutic suc-
cess. Radial ESWT was followed by a decrease of the com-
posite score of heel pain by 72.1%, compared with 44.7%
after placebo. With regard to the third a priori–ordered
hypothesis (single success rate of heel pain when taking
first steps of the day) the benchmark of significance was
just missed (P=.0269, 1-sided). Thus, the results of the fol-
lowing 2 a priori–ordered hypotheses have to be inter-
preted exploratorily. Nevertheless, the results of the fourth
and fifth a priori–ordered hypotheses (single success rate
of heel pain while doing daily activities and single success
rate of pain after application of the Dolormeter) demon-
strated superiority of the ESWT group with P values below
the level of significance (P=.0014, and P=.0216, respec-
tively, Table 2). Furthermore, the Mann-Whitney effect size
6Gerdesmeyer et al The American Journal of Sports Medicine
demonstrated more than small superiority of rESWT for
all 5 a priori–ordered hypotheses compared with placebo
(Mann-Whitney effect size >0.56), demonstrating signifi-
cant as well as clinically relevant effects.
Regarding follow-up 2 (12 months after rESWT) the P
values of all 5 primary efficacy criteria were far below the
predefined level of significance (.025, 1-sided, exploratory
interpretation, Table 2). Nonresponders of follow-up 1
period and premature discontinuations were included by
LVCF replacement of missing values and for safety analy-
sis. These results even demonstrated a pronounced treat-
ment effect at follow-up 2, and treatment success was
maintained. The composite VAS score of the heel pain was
–84.8% in the patients treated actively and –43.2% in the
placebo group (P <.025). Thus, there is strong evidence for
long-term superiority of the ESWT treatment compared
with identical placebo.
To assess the stability of the results, different sensitivity
analyses were performed for the primary efficacy criteria
at follow-up 1 and 2 assessing a per-protocol analysis, a
supportive analysis for the ITT data set without any cor-
rection for interfering analgesic therapy, a further sup-
portive sensitivity analysis for the ITT data set with
correction for interfering analgesic therapy by means of
the worst rank score technique, and an analysis of the data
set with the “data as available” instead of LVCF replace-
ment of missing values. All in all, the results of the sensi-
tivity analyses support the results of the confirmatory
analysis (see Appendix D for details, available online at
http://ajs.sagepub.com/supplemental/).
Secondary Outcome Measures
The efficacy results demonstrated superiority of the rESWT
group not only in the confirmatory analyses, but also in the
supportive sensitivity analyses and in the analysis of the sec-
ondary outcome measures. All tested secondary efficacy cri-
teria, including the SF-36 score, the Roles and Maudsley
Score, global judgment of effectiveness, therapy satisfaction,
and therapy recommendation, showed better outcome at the
primary endpoint in favor of the rESWT group, and all test
results were statistically significant (P <.025 1-sided).
Furthermore, all Mann-Whitney effect sizes denoted more
than small superiority of the rESWT group compared with
placebo (Table 3). Thus, there is evidence for benefit of
patients with painful heel by rESWT treatment not only
through reduced pain but also by generally improved well-
being. The positive result was also reflected by the high rec-
ommendation rate of participants with rESWT treatment
with a final recommendation of study therapy in 91.2% of the
rESWT group compared to 69.1% of the participants with
placebo intervention.
Adverse Events and Safety Criteria
A total of 251 subjects received at least one treatment ses-
sion (“safety population”; Figure 1). There were 50 device-
related adverse events in 33 patients of the rESWT group
and 11 adverse events in 10 subjects in the placebo group.
A total of 46 of 50 device-related nonserious adverse events
in the ESWT group was due to pain and discomfort during
treatment as displayed in Figure 2. The duration of dis-
comfort was reported as maximal 10 minutes mostly, and
no participant requested local anesthesia during rESWT,
even though this was offered to all patients. Device-related
adverse events had no influence on outcome. No adverse or
severe adverse event occurred regarding tendon rupture
observation, Semmes-Weinstein 5.07 (10 g) Monofilament
Assessment, Toe Clawing Observation, and Ankle-Brachial
Assessment.
At the primary endpoint 12 weeks after the last treatment,
the tolerability of the treatment was judged by the investiga-
tor as “very good” or “good” in 93.8% of the rESWT subjects
and in 90.1% of the placebo group.
DISCUSSION
The present placebo-controlled study was conducted to
investigate the safety and effectiveness of rESWT in the
treatment of recalcitrant plantar fasciitis. Plantar fasciitis
is a common complaint and can be especially disabling in
TABLE 1
Demographic and Baseline Characteristics of the ITT (Intent-to-Treat) Population of 243 Patientsa
ESWT ITT Placebo ITT PValue
Characteristic (n =125); mean ±SD (n =118); Mean ±SD (2-Sided)
Age, y 52.4 ±12.0 52.0 ±10.5 .6400
Male gender, % 30.40 33.05 .6809
Body mass index 27.2 ±4.73 28.0 ±4.98 .1602
Heel pain duration, mo 25.6 ±26.1 24.9 ±25.3 .9518
Heel pain (VAS) when taking 7.5 ±1.49 7.5 ±1.57 .8726
first steps in the morning
Heel pain (VAS) while doing 7.3 ±1.48 7.1 ±1.53 .1929
daily activities
Heel pain (VAS) after application 7.2 ±1.73 7.1 ±1.75 .4166
of the Dolormeter
Roles and Maudsley score 3.5 ±0.52 3.5 ±0.57 .8029
aESWT, extracorporeal shock wave therapy; SD, standard deviation; VAS, visual analog scale.
Vol. X, No. X, XXXX Efficacy of rESWT in Chronic Recalcitrant Plantar Fasciitis 7
athletes.1,4,29,31 Goals of treatment are pain relief and
restoration of function. Martin et al24 and Crawford and
Thomson8reviewed numerous studies of nonsurgical treat-
ment for plantar fasciitis such as stretching, cryotherapy,
heel cushions and shoe inserts, night splints, custom-made
orthotics, anti-inflammatory drugs, corticosteroid injec-
tion, and immobilization and showed success rates ranging
from 44% to 90%.1,4,8,24 Nevertheless, not more than lim-
ited evidence of efficacy could be demonstrated.4,8 For
patients with chronic heel pain resistant to nonsurgical
treatment, surgical interventions are suggested. Surgery,
however, can be associated with prolonged healing8,9 and
did not prove superior to ESWT.9,38
Extracorporeal shock wave therapy for plantar fasciitis
has been investigated in multiple well-designed, random-
ized, and placebo-controlled trials, providing evidence of
effectiveness and safety of treatment.17,23,27,29,30,31,33 These
studies also demonstrated significant influence of treat-
ment regimen and concomitant anesthesia on outcome.19,30
Notably, some double-blind randomized, controlled trials
that failed to show the superiority of ESWT over placebo
focused the acoustic energy at anatomical landmarks
rather than at the point of greatest tenderness as defined
by the participant, and local anesthesia was used in some
of the investigations in an effort to blind the partici-
pants.5,18,32 Recent studies have demonstrated that local
anesthesia may inhibit direct analgesic effects like the
modification of the release of pain mediators, hyperstimu-
lation, and the gate-control mechanism.18,21,22,28,37 These
observations were further supported by a study by Rompe
et al30 demonstrating ESWT applied without local anes-
thesia to be significantly more effective than ESWT used
with local anesthesia.
Compared with focused shock wave applicators, rESWT
devices address larger treatment areas, thus providing
potential advantages in superficial applications like
tendinopathies and skin conditions.7,15,16,28 For deep soft
tissue treatments or bone injuries, the radial technique
has some limitations regarding penetration depth and
higher energy levels.7,15,16 In contrast to so-called focused
shock wave therapies, the radial technique is used to treat
the painful region rather than a painful point. It is well
known that heel pain originates from a painful area along
the plantar fascia rather than a certain locally limited
spot. From the technical point of view, radial shock wave
therapy addresses more the area of pathologic changes
compared with focused devices.10,15,22,30 Due to the patient-
controlled application and the missing need to control the
TABLE 2
Changes of Primary Efficacy Criteria From Baseline at 12 Weeks (Follow-up 1) and 12 Months (Follow-up 2)a
Follow-up 1 (12 weeks) Follow-up 2 (12 months)
MW Effect MW Effect
Size, Size,
Primary Efficacy ESWT Placebo PValue (1-Sided 97.5 ESWT Placebo PValue (1-Sided 97.5
Criterionb(NITT =125) (NITT =118) (1-Sided) % LB-CI) (NITT =125) (NITT =118) (1-Sided) % LB-CI)
Composite score of –72.1 –44.7 .0220d0.5753 –84.8 –43.2 .0086d0.5879
heel pain (VAS)c(–56.0 ±39.3) (–44.1 ±41.8) (0.5023) (–61.9 ±43.6) (–46.5 ±45.5) (0.5159)
percentage change
from baseline, median
(mean ±SD)
Overall success rate of 60.98 42.24 .0020f0.5937 63.41 43.97 .0014f0.5972
heel pain(VAS)e, % (n) (75) (49) (0.5314) (78) (51) (0.5352)
Success rate of heel pain 60.80 48.31 .0269f0.5625 61.60 47.46 .0144f0.5707
(VAS) when taking first (76) (57) (0.5003) (77) (56) (0.5087)
steps in the morning, % (n)
Success rate of heel pain 60.00 40.68 .0014f0.5966 64.00 41.53 .0002f0.6124
(VAS) while doing daily (75) (48) (0.5349) (80) (49) (0.5512)
activities, % (n)
Success rate of heel pain 52.85 39.66 .0216f0.5660 59.35 43.10 .0063f0.5812
(VAS) after application (65) (46) (0.5033) (73) (50) (0.5187)
of the Dolormeter, % (n)
aEWST, extracorporeal shock wave therapy; ITT, Intent-to-Treat; MW, Mann-Whitney; LB-CI, lower bound of confidence interval; VAS,
visual analog scale.
bAll results with LVCF replacement of missing values and score correction for interfering concomitant therapy.
cSum score of heel pain (VAS) when taking first steps of the day, heel pain (VAS) when doing daily activities, and heel pain (VAS) after
application of the Dolormeter.
dPvalues of 1-sided test for superiority using the Wilcoxon-Mann-Whitney test.
ePercentage decrease of heel pain >60% from baseline for at least 2 of 3 heel-pain VAS measurements.
fPvalues of 1-sided test for superiority using the Unconditional Exact Röhmel-Mansman test.
8Gerdesmeyer et al The American Journal of Sports Medicine
focus zone, radial shock wave therapy seems to be easier to
apply.15,20 Because treatment regimen and shock wave
parameters have significant influence on outcome, pooling
of data in systematic reviews and meta-analyses is critical,
and effectiveness has to be assessed for the different
devices and treatment protocols.5,17,27,32,33,35 Buchbinder
et al5and Haake et al18 used local anesthesia or nerve
blocks and found no difference. When no local anesthesia
TABLE 3
Changes of Secondary Efficacy Criteria From Baseline at 12 Weeks (Follow-up 1) in the ITT Populationa
Follow-up 1 (12 weeks)
Secondary Efficacy Criterion ESWT (n =125) Placebo (n =118) PValue (1-sided) MW Effect Size
SF-36 physicalbpercentage change from –44.1 (–37.2 ±48.42) –23.9 (–19.5 ±52.13) .0013c0.6191
baseline at 12-week follow up,
median (mean/SD)
SF-36 mentalbpercentage change from –22.8 (–14.6 ±62.89) –14.3 (8.4 ±99.06) .0163c0.5850
baseline at 12-week follow up,
median (mean/SD)
Roles and Maudsley Scored: 58.40 (73) 41.52 (49) .0031c0.5973
“excellent” or “good,” % (n)
Investigator’s global judgment of 70.80 (80) 40.91 (45) .0002c0.6335
effectiveness: “very good” or “good,” % (n)
Patient’s global judgment of therapy 63.16 (72) 46.36 (51) .0045c0.5984
satisfaction: “very satisfied” or
“moderately satisfied,” % (n)
Patient’s recommendation of therapy 91.23 (104) 69.09 (76) <.0001e0.6107
to a friend, % (N)
aITT, intention-to-treat; ESWT, extracorporeal shock wave therapy; MW, Mann-Whitney; SD, standard deviation.
bSF-36 scales are standardized using a scale from 0 (best score) to 100 (worst score).
cPvalues of 1-sided test for superiority using the Wilcoxon-Mann-Whitney test.
dResults of Roles and Maudsley score with LVCF replacement of missing values and score correction for interfering concomitant therapy.
ePvalues of 1-sided test for superiority using the Unconditional Exact Röhmel-Mansman test.
0
10
20
30
40
50
60
pain/discomfort reddening swelling numbness unspecified foot
pain
A
0
1
2
3
4
5
6
7
8
pain/discomfort reddening swelling numbness
B
Figure 2. A, device-related adverse events in the radial extracorporeal shock wave therapy group. B, device-related adverse
events in the placebo group.
Vol. X, No. X, XXXX Efficacy of rESWT in Chronic Recalcitrant Plantar Fasciitis 9
was used, Gollwitzer et al,17 Rompe et al,30 and Malay
et al23 found significantly better outcome after shock wave
treatment. In the present study, radial shock waves were
oriented without anesthesia by patient-guided feedback to
the point of maximum tenderness.
The present randomized, placebo-controlled study
demonstrated significant improvement of pain scales and
functional measurements, as well as quality of life, after
rESWT at follow-up compared to baseline. Furthermore,
rESWT proved superior to placebo with regard to the pri-
mary outcome measures of “changes in VAS composite score
of heel pain” and “overall success rate” at 12 weeks and all
secondary outcome measures at 12 months after interven-
tion. At the time of follow-up 1, the VAS composite score
was reduced by 72.1% in the rESWT group compared with
44.7% in the placebo group, which was statistically signifi-
cant. Furthermore, the between-group difference of nearly
30% is considered clinically relevant.13 The superiority of
rESWT compared with placebo was not only limited to the
primary criterion of effectiveness but also strongly sup-
ported by the results of the outcome measures’ overall suc-
cess rate, success rate of heel pain while doing daily
activities, success rate of heel pain after the application of
the Dolormeter, Roles and Maudsley score, percentage
changes from baseline of the SF-36 summary measures
mental and physical health, investigator’s and patient’s
judgment of effectiveness, and the patient’s rate of recom-
mendation of the applied therapy to a friend. An additional
assessment of the Mann-Whitney effect size revealed more
than small superiority of rESWT in all determined criteria
both at 12 weeks and at 12 months after the intervention.
Furthermore, several sensitivity analyses were performed
to check the stability of the data, which all corroborate
effectiveness of rESWT compared with placebo showing sig-
nificant superiority (see Appendix D, available online at
http://ajs.sagepub.com/ supplemental/).
Regarding the second follow-up at 12 months after shock
wave treatment, superiority of rESWT compared with
placebo was even more pronounced, with a reduction of the
VAS composite score from baseline of 84.8% after shock
wave treatment compared with 43.2% in the placebo
group, demonstrating a more than 40% between-group dif-
ference. All other outcome measures also showed superior-
ity of the rESWT group, thus proving excellent long-term
efficacy and supporting the application of rESWT in the
treatment of chronic plantar fasciitis. Apart from the
investigated pain scales, we were able to demonstrate sig-
nificant improvement in the scores evaluating quality of
life (SF-36) and function (Roles and Maudsley score). Thus,
there is evidence for benefit of patients with painful heel
by ESWT treatment not only through reduced pain but
also by generally improved well-being.
Treatment was applied without anesthesia, and our
results demonstrated rESWT to be safe with excellent tol-
erability. The results demonstrate that patients assigned
the rESWT were found to have more pain during treat-
ment compared with placebo but no one required any local
anesthetic. The sensitivity analysis demonstrates no dif-
ferences in outcome with regard to all side effects.
From the clinical point of view, the outcome regarding
recommendation and global judgment by patients and
investigators demonstrated high clinical impact and
acceptance. Notably, nearly 70% of patients of the placebo
group would also recommend the received treatment to a
friend. This large placebo effect demonstrates the effec-
tiveness of the blinding technique, which also was found in
other randomized, controlled studies.17,23,35 In review, with
a mean improvement of the VAS composite score of more
than 40% in the placebo group at follow-up compared with
baseline, the power of the placebo effect in these kinds of
studies becomes obvious and has to be addressed by ran-
domized, placebo-controlled studies to analyze the pure
placebo effect. The associated placebo effect is related to
the device itself but also to the procedure and the physi-
cian.26,34,36 The pure treatment effect and the associated so-
called placebo effect are not distinguishable and clinically
used together.26,34,36
Radial ESWT demonstrated safety and effectiveness
with a protocol of 3 consecutive treatments (3 ×2000
impulses, 0.16 mJ/mm2), applied without anesthesia to the
spot of greatest tenderness. Radial ESWT can be strongly
recommended for patients with therapy-resistant plantar
painful heel syndrome. Especially in the cases of failed
nonsurgical treatment, rESWT represents an excellent
alternative to surgery because anesthesia is not required
and long recovery times are avoided. In addition, partici-
pants were not required to refrain from any sports activi-
ties during the course of the study. Furthermore, rESWT
represents an effective treatment modality that can be
administered on an outpatient basis.
ACKNOWLEDGMENT
The study was supported by Electro Medical Systems,
Nyon, Switzerland. The sponsor of the study did not have
any influence on data collection, analysis, or publication.
No constraints were placed on publication of the data.
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