Abstract
Background: Plantar fasciitis is a common foot disorder that may be
resistant to nonoperative treatment. This study evaluated the use of
electrohydraulic high-energy shock waves in patients who failed to respond to
a minimum of six months of antecedent nonoperative treatment.
Methods: A randomized, placebo-controlled, multiply blinded,
crossover study was conducted. Phase 1 consisted of twenty patients who were
nonrandomized to treatment with extracorporeal shock waves to assess the
phase-2 study protocol. In phase 2, 293 patients were randomized and an
additional seventy-one patients were nonrandomized. Following ankle-block
anesthesia, each patient received 100 graded shocks starting at 0.12 to 0.22
mJ/mm2, followed by 1400 shocks at 0.22 mJ/mm2 with use
of a high-energy electrohydraulic shock-wave device. Patients in the placebo
group received minimal subcutaneous anesthetic injections and nontransmitted
shock waves by the same protocol. Three months later, patients were given the
opportunity to continue without further treatment or have an additional
treatment. This allowed a patient in the active treatment arm to receive a
second treatment and a patient who received the placebo to cross over to the
active treatment arm. Patients were followed at least one year after the final
treatment.
Results: Treatment was successful in seventeen of the twenty phase-1
patients at three months. This improved to nineteen (95%) of twenty patients
at one year and was maintained at five years. In phase 2, three months after
treatment, sixty-seven (47%) of the 144 actively treated patients had a
completely successful result compared with forty-two (30%) of the 141
placebo-treated patients (p = 0.008). At one year, sixty-five of the
sixty-seven actively treated, randomized patients maintained a successful
result. Thirty-six (71%) of the remaining fifty-one nonrandomized patients had
a successful result at three months. For all 289 patients who had one or more
actual treatments, 222 (76.8%) had a good or excellent result. No patient was
made worse by the procedure.
Conclusions: The application of electrohydraulic high-energy shock
waves to the heel is a safe and effective noninvasive method to treat chronic
plantar fasciitis, lasting up to and beyond one year.
Level of Evidence: Therapeutic study, Level I-1a
(randomized controlled trial [significant difference]). See Instructions to
Authors for a complete description of levels of evidence.
Extracorporeal shock waves have been applied since 1990, principally in
Europe, for the treatment of numerous musculoskeletal
disorders1-4.
One of the initial treatment concepts was the noninvasive dissolution of a
calcific mass in the rotator cuff, similar to the break-up of a kidney stone
(lithotripsy)5-7.
Several musculoskeletal entities that have been treated include calcific
tendinitis of the shoulder, lateral epicondylitis, delayed union and nonunion
of fractures, chronic plantar fasciitis, Achilles and patellar tendinopathies,
and osteonecrosis of the femoral
head1-9.
Basic-science studies increasingly are providing an understanding of the
physiologic mechanisms of pain relief (often immediate) and the modification
and repair of the target tissue, which usually requires weeks to months to
occur10-29.
Extracorporeal shock-wave treatments have been applied to patients with
chronic plantar fasciitis who have failed to respond to multiple conservative
pharmacologic and therapeutic
interventions29-38.
Recent randomized, controlled studies have been published but with varying
results because of differences in study design, direction of the shock-wave
delivery, energy levels, size (volume) of the focused energy ellipsoid
(f2) that is transcutaneously transmitted to the fascia, and method
of forming the shock wave (electrohydraulic, electromagnetic, and
piezoelectric)32,39-52.
One study found that satisfactory results were maintained five years following
electromagnetic shock-wave
treatment43.
Randomized, placebo-controlled clinical trials for musculoskeletal
applications of high-energy shock waves have been conducted in the United
States43,46.
One trial led to Food and Drug Administration approval of the use of
electrohydraulic high-energy extracorporeal shock waves for the treatment of
plantar fasciitis in October
200044,53.
The present study assessed both the short and long-term results of the
application of high-energy electrohydraulic shock waves in the treatment of
plantar fasciitis. We hypothesized that the likelihood of a successful result
would be better in patients receiving active treatment than in patients
receiving a placebo. We further hypothesized that nonrandomized patients would
have an outcome equal to or greater than that for the treated randomized
patients.
This study was conducted between 1996 and 2003. Phase-1 and phase-2
protocols were approved sequentially by the Food and Drug Administration.
Study approvals were for a specific shock-wave generation device, the OssaTron
(Health-Tronics Surgical Services, Marietta, Georgia, and High Medical
Technologies, Lengwil, Switzerland). This device generates repetitive,
high-energy shock waves by the electrohydraulic method and transmits them
transcutaneously through the plantar skin into the target tissue. At all
participating institutions, the study was conducted by members of the
Department of Orthopaedics and was approved by the institutional review
board.
Phase 1 involved the nonrandomized application of extracorporeal shock
waves to patients with chronic plantar fasciitis to assess any procedural or
safety risks, to judge the potential efficacy, and to assess the planned
phase-2 study protocol. All phase-1 study patients received active shockwave
treatments. The phase-1 patients were allowed to receive a second treatment at
three months if they were dissatisfied with the initial results, on the basis
of the four outcome criteria proposed for phase 2.
Phase 2 involved a prospective, randomized, placebo-controlled, physician
and patient-blinded, multicenter evaluation to determine both the safety and
the effectiveness of this treatment method. Patients who received an actual
treatment were given the opportunity to have a second treatment if they failed
one or more of the four specific primary outcome parameters. Patients who
received a placebo treatment similarly could choose to receive one or two
actual treatments (cross over). All retreatment and crossover treatment
decisions were made, according to protocol, three months after the initial
treatment.
Patients were not informed as to which study arm they were in initially. An
additional group of nonrandomized patients was treated to allow training of
the physician investigators. These patients also were given the option of a
second treatment at three months if they failed any of the outcome parameters.
All of these nonrandomized patients in the training arm, who were comparable
with phase-1 patients, were aware that they had an actual treatment.
A minimum of two physician investigators participated at each study site.
One investigator served as the treatment-blinded evaluator, both for the
baseline patient assessment (according to specific inclusion and exclusion
criteria detailed in the Appendix) as well as for the follow-up evaluations.
This physician was not allowed to observe patient treatment. The actual
procedure was performed by a second trained physician who was aware of the
specific treatment rendered (with use of a sealed randomization envelope), but
who did not play any role in evaluating the patient before or after
treatment.
Subjects were randomized with use of blocks stratified by study site.
Randomization was done by a statistician (Stat-Tech Services) using numbered
envelopes that were prepared at a central facility and subsequently
distributed to each treatment facility. When a patient was to be treated, the
study coordinator was contacted and randomly assigned a specific numbered
envelope for the patient.
In both phases of the overall study, chronic heel-pain syndrome was defined
as moderate-to-severe heel pain in the involved foot at the origin (enthesis)
of the proximal plantar fascia at the medial calcaneal tuberosity that had
persisted for at least six months.
There were three important criteria for inclusion in the study. (1) The
patient had to have failed to respond after at least three attempts of
interventional conservative treatment, which could include at least two prior
courses of physical therapy (Achilles tendon and plantar fascia-stretching
exercises) and the use of orthotic devices (heel cup, molded shoe insert,
night splint, or cast) and at least one prior course of pharmacologic
treatment (aspirin, acetaminophen, nonsteroidal anti-inflammatory drug, or
corticosteroid injection). If the patient had a corticosteroid injection,
extracorporeal shock waves were not administered unless at least four weeks
had elapsed since the injection. (2) The objective assessment of pain in the
proximal plantar fascia by an investigator, using a pain measurement pressure
device (dolorimeter), was =5 cm on a 10-cm visual analog
scale54,55.
(3) The patient self-assessment of pain after the first five minutes of
walking in the morning was =5 cm on the 10-cm visual analog scale.
All patients underwent monofilament sensory testing (10-g retractable
monofilament; Smith and Nephew, German-town, Wisconsin) according to
Semmes-Weinstein criteria to screen for possible peripheral
neuropathy56-58.
Any patient who tested positive at two or more of ten sites was excluded from
the study. Monofilament testing also was done at each post-treatment
evaluation.
Patients with bilateral involvement were allowed to have treatment of only
one foot. However, these patients were discouraged from participating during
the enrollment evaluation because of the possible pharmacologic treatment of
the contralateral heel at or near the critical three-month evaluation point
that might adversely affect one of the four primary outcome criteria. Any
patient with pain in the contralateral heel of >4 on the visual analog
scale was excluded from the study.
Patients filled out a Short Form-36 (SF-36)
questionnaire59
before treatment and at three months and twelve months after treatment. All
patients also were given specific self-assessment questions regarding pain at
rest, pain with activity throughout the day, level of participation in
recreational activities, and the ability to work.
All patients had radiographs of the heel made in three views during the
pretreatment evaluation, at three months after treatment, and at the final
follow-up evaluation at one year. The presence or absence of a plantar heel
spur was documented. The presence of intraosseous lesions, such as a calcaneal
cyst or subtalar arthritis, was exclusionary.
The blinded investigator (evaluator) used a pressure sensor (dolorimeter)
to document objectively the amount of pressure (lb/in2) that, when
applied to the site of maximum tenderness, elicited from the study subject a
subjective baseline visual analog scale response duplicating maximum daily
pain. At each subsequent posttreatment evaluation, the same baseline
dolorimeter pressure was applied and the patient was asked to requantify the
current amount of pain using the visual analog scale response. This method
ensured consistency of the objective pressure evaluation, while allowing for
the subjective evaluation, by the patient, of changes in the amount of pain
perceived at the time of follow-up.
Patients were treated in an outpatient surgical center. Prior to
ankle-block anesthesia, the point of maximum plantar surface tenderness was
demarcated (targeted) with a surgical marking pen. The involved leg was draped
from the direct view of the patient. Ear protection devices were used by the
study subject and all involved personnel. Patients received either a complete
ankle-block anesthesia with lidocaine (the treatment group) or three 1-mL
subcutaneous injections of lidocaine (the placebo group) prior to the
application of shock waves. The shock-wave treatments were applied with use of
the OssaTron device. Standard ultrasound gel was applied to the heel for
transcutaneous conduction of the shock waves from the OssaTron into the heel
tissues. The device was adjusted to maximize the focused treatment wave
(f2) into the plantar
fascia60. Each
study subject assigned to active treatment received 100 graded shocks (14 to
18 kV; 0.12 to 0.22 mJ/mm2) to assess the effectiveness of
anesthesia, followed by 1400 shocks at 18 kV (0.22 mJ/mm2) for a
total of 1500 shocks, all of which were applied at two per second (2 Hz). The
total energy delivered was 324.25 J. The treating physician continually
manipulated the heel against the treatment head throughout the shock-wave
applications. Shock waves thus were applied to the maximum pain site as well
as an area in a 1-cm radius surrounding it.
For the patients assigned to placebo treatment, a styrofoam block was
placed against the treatment head to absorb the shock waves by the presence of
the multiple air cavities. In addition, a fluid-filled intravenous bag was
placed between the styrofoam block and the subject's heel to mimic the
water-filled treatment head. Patients who received a placebo treatment did not
have any coupling gel (ultrasound gel) applied to the heel. Placebo patients
also had 1500 shocks "delivered" according to the aforementioned
gradation protocol, effectively duplicating the duration and noise of an
active treatment. Patients who received the placebo treatment and patients who
received the active treatment were kept apart in the recovery room to avoid
any discussions and comparisons about what occurred in the surgical suite.
All patients underwent evaluations within forty-eight hours following
treatment and at one, two, three, six, nine, and twelve months. In both phase
1 and phase 2, an initial success or failure status was assigned on the basis
of the subjective and objective findings three months after the initial
treatment. This three-month interval was selected on the basis of the
expectation that some or all of the healing process most likely would be
evident at that time. Subsequently, patients either were followed to one year
without additional intervention or received additional treatment followed by
periodic evaluations until one year following the additional treatment.
Patients were encouraged to continue follow-up beyond one year.
At three and twelve months, patients were assigned a success or failure
status according to each of four predetermined primary criteria. (1) On the
investigator assessment of pain, the patient had to have a minimum improvement
of 50% over the dolorimeter-induced baseline pain score, with a required score
of =4 on the visual analog scale. (2) On the patient self-assessment of
pain on first walking in the morning, success required a minimum improvement
of 50% over the pretreatment baseline and a visual analog scale score of
=4. (3) On the patient self-assessment of activity with regard to the
distance and time that he or she was able to walk without heel pain, the
patient had to demonstrate an improvement of =1 point on a 5-point scale or
had to maintain a 0 or 1 baseline level (no pain or minimal pain). (4) With
regard to the use of pain medications, prescription analgesics were not given
after treatment. Self-treatment with over-the-counter analgesics or
anti-inflammatory medications was documented with a medication log returned at
each evaluation. Success required that the patient had not taken any such
medication (even for a reason other than pain in the treated heel) between ten
and twelve weeks after treatment.
Each patient in the randomized group unequivocally had to meet all four
success criteria to attain an overall status assignment of success.
Patients who were assigned a failure status at three months were informed
that they could (1) withdraw from the study to pursue alternative treatment
modalities or (2) continue in the study by trying an additional active
treatment as allowed by the study protocol. All evaluations of retreatment or
crossover from placebo to active treatment were done according to the same
protocol as for the primary treatment-placebo study arm.
The patients who elected to receive an additional treatment or treatments
were classified arbitrarily as having a failure of the initial treatment. All
patients receiving additional treatment were followed according to the same
protocol (with evaluations at one, two, three, six, nine, and twelve months)
after the last applied shock-wave treatment.
If patients did not complete the twelve-month follow-up protocol, efforts
were made to encourage compliance. Any patient who failed to respond to these
efforts was classified as a failure in the outcome assessment.
Patient acceptance into the study, data collection, and analysis were
further blinded. At each center, a research assistant collected questionnaire
data (subject self-assessments and SF-36) independently of the evaluating
physician. Individual centers were not allowed to communicate with each other.
Data from all centers were sent to an independent organization,
M2 and Associates,
for composite compilation and initial analyses. Final data sets and analyses
were then sent to an outside statistician, Stat-Tech Services, to validate the
results.
Univariate analyses were performed with use of the Pearson chi-square
statistic. Multiple logistic regression was used to test jointly the
explanatory variables that were significant in the univariate analyses. The
adjusted odds ratios were presented with the respective 95% confidence
intervals. Significance was considered at a two-tailed level of <0.05.
The study sample size was obtained on the basis of the need to collect
sufficient safety information. The original efficacy sample size was
calculated on the basis of an assumed response of 70% in the active treatment
arm and 30% in the placebo arm, which was smaller than the sample size
required for adequate safety information. Additional subjects were added after
the study sample size was reached in order to allow continued patient access
and obtain additional safety information.
The primary efficacy analysis was based on the success status at three
months. The p value for the inferential evaluation of the null hypothesis of
no treatment effect was obtained with use of a likelihood ratio test
controlling for study site. The test statistic was obtained by evaluating the
difference in log-likelihood for the logistic model including the study site
and treatment and the logistic model including only the study site. The
Pearson chi-square test also was used to evaluate the null hypothesis that
there was no association between treatment and response at three months.
To investigate the durability of the response through six months and one
year, the time-to-failure after the initial treatment was compared with use of
Kaplan-Meier methodology, and inference was based on the log-rank statistic.
Substantially more follow-up data were available to support this analysis than
were available for the three-month analysis at the time of the initial Food
and Drug Administration submission. The proportion of six-month and one-year
responders was compared, with use of a Pearson chi-square test, for all
subjects who had six months of follow-up data. A two-tailed Fisher exact test
was used to compare the distribution of successful outcomes at three months
for the patients who had retreatment with electrohydraulic shock waves and the
patients who initially had the placebo treatment. Secondary efficacy measures
of the visual analog scale scores for pain were summarized at each visit
through six months. The six-month and one-year time-points included only
subjects who were responders at three months. The hypothesis of no treatment
difference in the mean percentage change from baseline was evaluated with use
of a t test assuming equal variance.
Selected demographic and baseline characteristics were assessed for
homogeneity in the subject population across sites and treatment groups. The
assessment of homogeneity was used to assist in the interpretation of the
efficacy and safety analyses. For categorical variables, a logistic modeling
approach was used. For continuous variables, a general linear modeling
approach was used and inference was based on p values associated with the
type-III sums of squares.
Deviations from planned analyses included use of an additional Pearson
chi-square test to compare the proportion of subjects with a successful
outcome at six months. No further confidence intervals were calculated, except
for the 95% confidence interval of the relative risk for success at three
months. Testing comparing the visual analog scale scores for the patients who
had retreatment with electrohydraulic shock waves and the patients who were
initially treated with placebo was not performed.
Twenty patients were enrolled in the phase-1 study
(Fig. 1). The treating and
evaluating physician was the same individual, and all patients knew that they
received active extracorporeal shock-wave treatment. Seventeen patients (85%)
had substantial improvement or complete relief of pretreatment symptoms at
three months. Three patients were not satisfied with the results at three
months and chose a second treatment. Two of the three had symptomatic
improvement, whereas one continued to have no improvement. All twenty patients
were followed to one year, with a good-to-excellent result maintained at one
year in nineteen54.
These nineteen patients reported continued relief of symptoms for sixty-five
to sixty-eight months later, and none had a recurrence of symptoms. The single
patient who had no symptomatic improvement continued to have chronic pain.
Phase 2 involved 344 patients, comprising 293 randomized and fifty-one
nonrandomized study subjects (Figs.
2 and
3). This patient population was
predominantly female (66.3%). The mean age of the subjects at the time of
enrollment was 48.6 years (range, nineteen to seventy-nine years; median [and
standard deviation], 49 ± 11.3 years). Age was not significantly
associated with the three-month outcome (p = 0.138). Gender, ethnicity, and
pretreatment osteoarthritis in other joints, such as the knee or the hip, were
not significantly associated with success or failure.
Of the 148 randomized patients who had an active treatment initially, 144
returned for all evaluations up to three months and eighty-nine continued to
twelve months. Of the 145 randomized patients who initially received a
placebo, 141 returned for evaluations at three months and sixty-four continued
to twelve months. Of the fifty-one nonrandomized patients, forty-seven
returned for evaluations at three months and thirty-six continued to twelve
months. Altogether 189 phase-2 patients (55%) cooperated in follow-up to at
least one year following the initial treatment.
Duration of Symptoms
All patient groups were similar with respect to the mean duration of
symptoms prior to shock-wave or placebo treatment. The duration of symptoms
was significantly associated with success (p = 0.001). Adjusting for the
duration of symptoms affected the overall significance of the association
between treatment and success (p = 0.004). The analysis divided the population
into patients with a shorter duration of pain (less than or equal to the
median duration) and those with a greater duration of pain (more than the
median duration). Patients with a shorter duration of symptoms had higher
response rates, and the absolute difference in the success rates between the
two patient groups was similar in magnitude. The difference in treatment
success rates was 13% (52% for the active treatment group compared with 39%
for the placebo group) for the patients with a shorter duration of pain and
20% (40% for the active treatment group compared with 20% for the placebo
group) for the patients with a longer duration.
Investigator Heel-Pain Assessment
All treatment groups had comparable baseline pain scores
(Table I). Evaluation of the
investigator assessment of heel pain at four, eight, and twelve weeks
indicated significant treatment effects as early as the four-week visit. The
percentage change (improvement) in investigator assessment of heel pain at
four, eight, and twelve weeks was 41%, 49%, and 59%, respectively, for active
treatment subjects compared with 27%, 32%, and 43%, respectively, for placebo
treatment subjects. The p values for the comparisons of active treatment
versus placebo at these visits were 0.018, 0.001, and 0.002, respectively.
This dolorimeter-based visual analog scale measurement at three months was the
most sensitive measure comparing patients who had received active treatment
with those who had been randomized to treatment with a placebo (p = 0.002).
This sensitivity was maintained at twelve months (p = 0.005).
Subject Self-Assessment of Morning Heel Pain
Baseline values were comparable (Table
II). For the patient self-assessment of morning heel pain, the
mean score at four, eight, and twelve weeks improved 45%, 50%, and 58%,
respectively, for the subjects who had active treatment and 31%, 39%, and 47%,
respectively, for the subjects who had placebo treatment. The p values for the
comparisons of active treatment and placebo effects at these visits were
0.002, 0.021, and 0.014, respectively. At twelve months, this difference was
maintained (p = 0.015).
Subject Self-Assessment of Activity-Related Pain
Baseline values were comparable (Table
III). For the patient self-assessment of pain with activity, the
mean score at four, eight, and twelve weeks improved 40%, 53%, and 51%,
respectively, for patients who had active treatment and 29%, 32%, and 47%,
respectively, for subjects who had placebo treatment. The p values for the
comparisons of active treatment and placebo effects at these visits were
0.024, 0.077, and 0.059, respectively. By twelve months, however, no
difference in subjective self-assessment of activity-related pain persisted
between the two groups.
Use of Pain Medications
This parameter had the least sensitivity to differentiate between actively
treated patients and those who received the placebo as success levels in both
groups were nearly identical. Furthermore, over 70% of the patients took
medications for pain in another body region than the treated heel.
Repeat Procedures
In phase 2, forty-seven (61%) of the seventy-seven patients who had active
treatment and were assigned to a failure status at twelve weeks chose to have
retreatment, whereas eighty-four (85%) of ninety-nine placebo-treated patients
with a failure status at twelve weeks chose to undergo an active
extracorporeal shock-wave treatment and nineteen had a second active
treatment. In the nonrandomized cohort, eleven (23%) of forty-seven patients
chose a second treatment. A total of 370 active extracorporeal shock-wave
treatments were performed in randomized and nonrandomized subjects. The
difference between the randomized, actively treated patients and the
placebo-treated patients with respect to the selection of a second treatment
was significant (p = 0.003).
At three months, twenty-two of forty-two patients who were initially
actively treated and received a second active treatment attained success. This
success was maintained in eighteen of the twenty-two patients at one year.
Three months after seventy-eight placebo-treated patients had crossover
treatment, thirty-six attained success. At one year, thirty-nine patients were
lost to follow-up. Of the remaining thirty-six patients, thirty had a
successful outcome. Three months after a repeat procedure, six of eleven
nonrandomized subjects had a successful outcome and six of eight had a
successful outcome at one year.
Complications
There were no complications in the phase-1 patients. The most frequent
phase-2-related complications in all groups were pain after treatment and mild
neurologic symptoms (numbness or dysesthesia) principally related to the
ankle-block anesthesia. All patients had complete resolution of the
post-treatment neurologic symptoms by the three-month evaluation, and no
patient had neurologic complaints at one year.
Rates of Treatment Success for Randomized Patients
Of the 144 phase-2 patients who were randomized to active treatment, 47%
met all four success criteria at three months compared with 30% of the 141
subjects who received placebo treatment (p = 0.008). Of the fifty-one
nonrandomized patients, 67% met all four success criteria. Of the eighty-four
patients who had been randomized to placebo treatment, failed to meet the four
success criteria, and subsequently elected to have an active treatment, 43%
subsequently achieved a success at three months. The time to treatment failure
was evaluated starting at three months and followed through to twelve months.
A significant difference was found when patients who had one or more
treatments (including crossover treatments) with success were compared with
patients (actively treated and placebo-treated) who were rated as having a
failure (logrank test, chi-square = 9.68; p = 0.0019).
The primary efficacy comparison for success of all four components of
efficacy at three months indicated a robust treatment effect (p = 0.003).
Accordingly, the relative risk for success at three months (active treatment
relative to placebo) was 1.56 (95% confidence interval, 1.15 to 2.13),
implying a >50% increase in the chance of success at three months with
active treatment compared with placebo.
In the phase-2 patients, the rate of success maintained at twelve months
was 93% for those initially treated actively, 83% for those who crossed over
from initial placebo treatment, and 93% for those who were not randomized. In
contrast, only twenty-five (18%) of the 141 patients who received the placebo
and chose no subsequent treatment at three months had a success at twelve
months. At twelve months, the differences between the actively treated
patients and the placebo-treated patients showed a continuing significance (p
= 0.002). Thirty-four patients subsequently were followed between twelve and
twenty-seven months, and all maintained the successful results. The overall
maintenance of a successful outcome was found to be significant (Fisher exact
test, p = 0.040).
Analysis of All Treated Patients
Although only the randomized patients were used for the initial three-month
and final one-year statistical analyses submitted to the Food and Drug
Administration, the results in all patients were subsequently assessed in a
clinically relevant manner with use of a grading system similar to one
commonly used in most published European musculoskeletal shock-wave outcome
studies61. Patients
who had initial visual analog scale scores (in the first three outcome
assessment categories) of >8 frequently met the criterion of 50%
improvement, but they failed to have a visual analog scale score of =4. All
289 phase-1 and 2 patients who received one or two actual shock-wave
treatments were grouped together and were rated as having an excellent result
if all four success criteria were met, a good result if two or three of the
four success criteria were met, a fair result if one of the four success
criteria were met, or a poor result if none of the four success criteria were
met.
With use of this grading system, 147 (50.9%) of 289 patients had an
excellent result and seventy-five (26%) had a good result
(Table IV), for a combined
total of 222 patients (76.8%) in whom the result was considered a success,
even when pain relief was not complete in one of the outcome categories.
Chronic heel pain that adversely affects employment or lifestyle is a
common complaint. A heel spur is evident in 50% to 60% of patients having a
diagnosis of heel pain. In one study, electrohydraulic shock waves delivered
at the energy level used for plantar fasciitis (18 to 20 kV; 0.22 to 0.27
mJ/mm2) caused no change in the heel spur when one was present nor
did the presence or absence of an inferior heel spur affect the likelihood of
a positive
response62.
The initial treatment of proximal plantar fasciitis should be conservative
(nonsurgical), an approach that may be successful in as many as 90% of
patients by providing substantial, if not complete, relief of the
symptoms63.
However, there is no consensus for a specific treatment protocol, particularly
when symptoms last for more than three months.
Evaluations of the nonoperative methods for treating chronic plantar
fasciitis have been difficult to assess statistically, since many protocols
have included multiple and variable nonoperative regimens within the same
study, and few nonoperative treatments have been analyzed with randomized
controlled
studies63. Martin
et al. reviewed numerous studies on nonoperative treatment and showed a wide
variation in acceptable outcomes, ranging from 44% to 82% (average, 60.3%) of
patients who had complete relief of heel
pain64.
Interestingly, in that study, only 51% of the patients were completely
asymptomatic following treatment, whereas 82% were satisfied with the final
outcome relative to the amount of residual
pain64. We found
similar outcome perceptions and satisfaction levels by the patients who
received shock-wave treatment; complete pain relief was not needed for patient
satisfaction with the eventual outcome.
Of interest was the lower than expected rate of retreatment in the active
treatment arm of study. The study was designed on the assumption that the
majority of subjects who failed to respond to the primary treatment would
elect to have a second treatment. However, forty-seven (61%) of the
seventy-seven treated subjects who failed to meet all four success criteria
chose retreatment compared with eighty-four (85%) of the ninety-nine patients
who failed the placebo treatment. This observation suggests that many subjects
who were assigned a final "fail" status (less than four of the
four criteria for success were met) may have been sufficiently satisfied with
the outcome that they did not want a second treatment.
When such noninvasive methods fail to achieve relief in a reasonable period
of time, surgery frequently is recommended. A recent study found that patients
undergoing electrohydraulic high-energy shock-wave application and patients
undergoing percutaneous partial fasciotomy had comparable
outcomes65.
However, the former group (patients who had extracorporeal shock waves) had a
more rapid return to the activities of work and daily living.
The technology of applying shock waves to the heel is similar to that used
for lithotripsy. Several devices have been designed specifically for the
treatment of musculoskeletal conditions. This is necessary since the energy
levels, the focused volume of the energy ellipsoid (f2), the
central size of the maximum energy level within the ellipsoid, and the depth
of penetration used in lithotripsy are different from those considered safe
and effective for musculoskeletal tissues that are not as deeply situated as
the kidneys and ureters. These musculoskeletal devices generate and focus the
shock waves by one of three basic methods—electrohydraulic,
electromagnetic, or
piezoelectric60.
The differences in shock-wave energy to the target tissue relate specifically
to the method of generation of the shock wave, the size and volume of the
f2 ellipsoid, and the depth of energy penetration. These factors
may result in significant differences in the potential clinical
efficacy2,60.
Comparison studies with lithotriptors (for renal stones only) have described
the electrohydraulic method as being more clinically effective in stone
fragmentation compared with electromagnetic or piezoelectric
devices66. The
machine used for the current musculoskeletal studies employed electrohydraulic
shock-wave generation and was the first shock-wave device approved by the Food
and Drug Administration for any musculoskeletal
indications53.
Since direct comparison studies of machines have not been done, there is no
information concerning the relative efficacy of one method of shock-wave
generation over any other for specific musculoskeletal tissue
applications60.
Electrohydraulic application is based on one treatment in most patients,
whereas electromagnetic and piezoelectric devices, as described in most
European-based publications, routinely use multiple (three to six)
treatments1,2.
Buchbinder et al. assessed a low-energy electromagnetic device in a
randomized, double-blind, placebo-controlled study with use of three
treatments49. They
found no differences between the patients who received active treatment and
those who received the placebo. This observation suggested that the overall
efficacy of low-energy, multiple shock-wave treatments for musculoskeletal
applications was questionable. However, such a generalization was
inappropriate because of limitations of that particular study (the patients
were treated as early as six weeks after symptom onset, actual shock waves
were delivered to placebo-treated patients, and variable numbers of shocks
[mJ/mm2 and total energy (Joules)] per patient were used) compared
with other studies. Furthermore, patients received no specific physical
examinations before and after treatment, and no orthopaedist was involved in
the study. A "trained technician" delivered the treatment after a
radiologist focused the device with use of ultrasound. In the current study,
patients had to have had symptoms for a minimum of six months, all patients
received exactly the same energy levels, shock waves were not delivered to
placebo patients, and trained orthopaedists actively participated in the
evaluation and treatment of the patients. When the Food and Drug
Administration approved the OssaTron device, one stipulation was that
treatment should be administered only by an appropriately trained and
certified physician or podiatrist.
Other studies on low-energy electromagnetic shock waves in which patients
received the same dosage and those treated with a placebo received no shock
waves, with delivery in a transverse direction, also showed no effective
difference between the actively treated patients and the patients who received
the
placebo50,51.
Those studies (compared with the present study on high-energy electrohydraulic
shock waves) suggested that there are different tissue responses to shock
waves contingent upon the method of generation (electrohydraulic or
electromagnetic), the level of energy applied, or the direction of delivery
(perpendicular to the plantar surface or transverse).
Low-energy electromagnetic and piezoelectric devices have an adjunct
ultrasound device that must be used to focus f2 because the
low-energy shock waves are delivered in a medial-to-lateral direction, rather
than perpendicular to the plantar surface. This technique delivers shock waves
to the thinnest portion of the fascia, which is done to minimize shock-wave
impaction against the calcaneus, thus avoiding pain stimulation and the need
for anesthesia. This technique requires additional expertise in ultrasound
imaging by the treating physician. With transverse delivery, the foot is held
in a fixed position. Accordingly, only a small section of the fascia is
impacted by the shock waves. In contrast, the electrohydraulic shock waves are
administered through the plantar surface (a wider surface area), targeting the
point of maximal pain, and the foot is continually manipulated to treat an
area 2 cm in diameter around the predetermined focal point of maximal pain.
Some of the shock waves strike the calcaneus and bone and are reflected back
into the involved fascia, potentially increasing the total effect of each
shock wave.
One study stated that the low-energy treatment was considered
"unpleasant by all
patients."32
Treatment with high-energy shock waves, particularly those generated
electrohydraulically, requires some type of anesthetic agent. In our study,
patients receiving the actual high-energy shock waves were administered an
ankle block. Since the approval of the device by the Food and Drug
Administration, we have also used conscious sedation. This anesthetic
technique also allows the treatment of both heels when appropriate levels of
chronic fascial pain are present
bilaterally67.
Rompe et al. performed several studies on the treatment of plantar
fasciitis with shock
waves4,32,39,43.
Those studies all used electromagnetically generated shock waves, involved
multiple treatments, and varied considerably with respect to the treatment
protocols. All outcome evaluations emphasized subjective improvement, rather
than complete relief of heel pain, and used outcome criteria that were much
less restrictive than those used in our study. In one study, Rompe et al.
recently reported on patients who had a successful outcome five years after
treatment with low-energy extracorporeal shock
waves43. Hammer et
al. reported on forty-four patients with chronic plantar fasciitis who were
treated with piezoelectric shock-wave
generation42. There
were no control patients. In twenty-four of forty-four patients (55%), the
visual analog scale improved; however, only thirteen patients (30%) rated the
outcome as completely successful.
The mechanism of shock-wave action in soft tissues (tendon and fascia) is
still under investigation. Rompe et al. showed no tendon cellular damage in a
rabbit model with use of energy levels normally applied clinically for the
treatment of plantar
fasciitis10,11.
They demonstrated neovascular proliferation as did Wang et
al.14,22.
When shock waves are applied to bone (at a much greater energy level and
number of shocks), microfractures and osteocyte damage occur, followed by a
proliferation of osteoblasts and elaboration of
bone1,2,4,17,20,23-26.
A similar microdisruption of the thickened plantar fascial origin probably
occurs, resulting in an inflammatory and soft-tissue reparative
response2,10,14.
This study presents robust evidence of a treatment effect. The primary
efficacy end point of success at three months and the analysis of sustained
response were both highly significant (p < 0.01). Analyses of the long-term
(one-year) response supported a continuing treatment difference. Hence, there
is ample evidence that electrohydraulically generated high-energy
transcutaneous shock-wave treatment is an effective treatment of heel pain due
to chronic plantar fasciitis when compared with placebo. We believe that our
data support the use of electrohydraulic high-energy shock-wave treatment
before consideration of any open or endoscopic surgical treatment.
A table showing the complete inclusion-exclusion criteria is available with
the electronic versions of this article, on our web site at
(go to
the article citation and click on "Supplementary Material") and on
our quarterly CD-ROM (call our subscription department, at 781-449-9780, to
order the CD-ROM).
Note: The authors acknowledge the multiple physicians and
support staff at the participating study sites, including Dirk Asherman, MD,
Judith Baumhauer, MD, James Beskin, MD, Raj Bholé, MD, Victor Brown,
DO, Roger Castillo, PA, Thomas Chi, MD, Mitchell Cooper, MD, Michael Coughlin,
MD, Greg Crawley, MD, G. Lee Cross, MD, Jeffrey DeLoach, DO, Benedict F.
DiGiovanni, MD, Russell Ellis, MD, Anthony Furguson, MD, Timothy M. Ganey,
PhD, Anthony Gatti, DPM, Jerome J. Gilden, MD, John S. Gould, MD, Ninoo
Hollis, MD, Juha Jaakkola, MD, Perry Julian, DPM, Ashok Kumar, MD, Gary
Lourie, MD, Gregory Lee, MD, John Marymont, MD, Troy Maxwell, James
McWilliams, MD, Deborah Nawoczenski, PT, PhD, Vinood Panchbahvi, Preti Patel,
Tim Petsche, MD, Douglas Powell, MD, William Ricci, MD, Felix Rodriguez del
Rio, MD, Sally Rudicel, MD, Harlan Selesnick, MD, Michael Shutte, MD, Pamela
Smith, RN, Brian Terry, MD, Davis Thornbury, MD, Saul G. Trevino, MD, Kevin
Varner, MD, James Voglino, MD, Peter Weiman, and Sharrona Williams, MD.
HellerKD,
Niethard FU. [Using extracorporeal shockwave therapy in
orthopedics—a meta-analysis.] Z Orthop Ihre
Grenzgeb.1998;136:
390-401. German.136390
1998
[CrossRef]
OgdenJA,
Alvarez RG, Levitt R, Marlow M. Shock wave therapy (Orthotripsy) in
musculoskeletal disorders. Clin Orthop.2001;387:
22-40.38722
2001
[PubMed][CrossRef]
RompeJD, Buch
M, Gerdesmeyer L, Haake M, Loew M, Maier M, Heine J. [Musculoskeletal
shock wave therapy—current database of clinical research.] Z
Orthop Ihre Grenzgeb.2002;140: 267-74.
German.140267
2002
[CrossRef]
RompeJD.Shock wave applications in musculoskeletal disorders.
New York: Thieme Medical Publishers; 2002. p
33-6.33
2002
PanPJ, Chou
CL, Chiou HJ, Ma HL, Lee HC, Chan RC. Extracorporeal shock wave therapy
for chronic calcific tendinitis of the shoulders: a functional and sonographic
study. Arch Phys Med Rehabil.2003;84:
988-93.84988
2003
[PubMed][CrossRef]
WangCJ, Yang
KD, Wang FS, Chen HH, Wang JW. Shock wave therapy for calcific tendinitis
of the shoulder: a prospective clinical study with a two-year follow-up.
Am J Sports Med.2003;31:
425-30.31425
2003
[PubMed]
GerdesmeyerL,
Wagenpfeil S, Haake M, Maier M, Loew M, Wörtler K, Lampe R, Seil R,
Handle G, Gassel S, Rompe JD. Extracorporeal shock wave therapy for the
treatment of chronic calcifying tendonitis of the rotator cuff: a randomized
controlled trial. JAMA.2003;290:
2573-80.2902573
2003
[PubMed][CrossRef]
PeersKH,
Lysens RJ, Brys P, Bellemans J. Cross-sectional outcome analysis of
athletes with chronic patellar tendinopathy treated surgically and by
extracorporeal shock wave therapy. Clin J Sport Med.2003;13:
79-83.1379
2003
[PubMed][CrossRef]
LudwigJ,
Lauber S, Lauber HJ, Dreisilker U, Raedel R, Hotzinger H. High-energy
shock wave treatment of femoral head necrosis in adults. Clin
Orthop.2001;387:
119-26.387119
2001
[CrossRef]
RompeJD,
Kirkpatrick CJ, Küllmer K, Schwitalle M, Krischek O. Dose-related
effects of shock waves on rabbit tendo Achilles. A sonographic and
histological study. J Bone Joint Surg Br.1998;80:
546-52.80546
1998
[PubMed][CrossRef]
RompeJD.
[Shockwave therapy: therapeutic effects in a speculative mechanism.]
Z Orthop Ihre Grenzgeb.1996;134: Oa13-9.
German.134Oa13
1996
[PubMed]
HaakeM, Wessel
C, Wilke A. [Effects of extracorporeal shock waves (ESW) on human bone
marrow cell cultures.] Biomed Tech (Berl).1999;44: 278-82.
German.44278
1999
[PubMed][CrossRef]
LinJH, Wang
MX, Wei A, Zhu W, Diwan AD, Murrell GA. Temporal expression of nitric
oxide synthase isoforms in healing Achilles tendon. J Orthop
Res.2001;19:
136-42.19136
2001
[CrossRef]
WangCJ, Huang
HY, Pai CH. Shock wave-enhanced neovascularization at the tendon-bone
junction: an experiment in dogs. J Foot Ankle Surg.2002;41:
16-22.4116
2002
[PubMed][CrossRef]
OrhanZ, Alper
M, Akman Y, Yavuz O, Yalciner A. An experimental study on the application
of extracorporeal shock waves in the treatment of tendon injuries: preliminary
report. J Orthop Sci.2001;6:
566-70.6566
2001
[PubMed][CrossRef]
TakahashiN,
Wada Y, Ohtori S, Saisu T, Moriya H. Application of shock waves to rat
skin decreases calcitonin gene-related peptide immunoreactivity in dorsal root
ganglion neurons. Auton Neurosci.2003;107:
81-4.10781
2003
[PubMed][CrossRef]
NarasakiK,
Shimizu H, Beppu M, Aoki H, Takagi M, Takashi M. Effect of extracorporeal
shock waves on callus formation during bone lengthening. J Orthop
Sci.2003;8:
474-81.8474
2003
[CrossRef]
MartiniL,
Giavaresi G, Fini M, Torricelli P, de Pretto M, Schaden W, Giardino R.
Effect of extracorporeal shock wave therapy on osteoblastlike cells.
Clin Orthop.2003;413:
269-80.413269
2003
[PubMed][CrossRef]
DorotkaR,
Kubista B, Schatz KD, Trieb K. Effects of extracorporeal shock waves on
human articular chondrocytes and ovine bone marrow stromal cells in vitro.
Arch Orthop Trauma Surg.2003;123:
345-8.123345
2003
[PubMed][CrossRef]
HsuRW, Tai CL,
Chen CY, Hsu WH, Hsueh S. Enhancing mechanical strength during early
fracture healing via shockwave treatment: an animal study. Clin
Biomech (Bristol, Avon).2003;18:
S33-9.18S33
2003
[CrossRef]
MaierM,
Averbeck B, Milz S, Refior HJ, Schmitz C. Substance P and prostaglandin E2
release after shock wave application to the rabbit femur. Clin
Orthop.2003;406:
237-45.406237
2003
[CrossRef]
WangCJ, Wang
FS, Yang KD, Weng LH, Hsu CC, Huang CS, Yang LC. Shock wave therapy
induces neovascularization at the tendon-bone junction. A study in rabbits.
J Orthop Res.2003;21:
984-9.21984
2003
[PubMed][CrossRef]
McClureSR, Van
Sickle D, White MR. Effects of extracorporeal shock wave therapy on bone.
Vet Surg.2004;33:
40-8.3340
2004
[PubMed][CrossRef]
WangFS, Wang
CJ, Chen YJ, Chang PR, Huang YT, Sun YC, Huang HC, Yang YJ, Yang KD. Ras
induction of superoxide activates ERK-dependent angiogenic transcription
factor HIF-1 alpha and VEGF-A expression in shock wavestimulated osteoblasts.
J Biol Chem.2004;279:
10331-7.27910331
2004
[PubMed][CrossRef]
MartiniL, Fini
M, Giavaresi G, Torricelli P, de Pretto M, Rimondini L, Giardino R.
Primary osteoblasts response to shock wave therapy using different parameters.
Artif Cells Blood Substit Immobil Biotechnol.2003;31:
449-66.31449
2003
[PubMed][CrossRef]
ChenYJ, Kuo
YR, Yang KD, Wang CJ, Huang HC, Wang FS. Shock wave application enhances
pertussis toxin protein-sensitive bone formation of segmental femoral defect
in rats. J Bone Miner Res.2003;18:
2169-79.182169
2003
[PubMed][CrossRef]
BuchM, Siebert
W. Shockwave treatment for heel pain syndrome—a prospective
investigation. In: Coombs R, Schaden W, Zhou SSH, editors.
Musculoskeletal shockwave therapy. London: Greenwich
Medical Media; 2000. p 73-7.73
2000
HsuRW, Hsu WH,
Tai CL, Lee KF. Effect of shock-wave therapy on patellar tendinopathy in a
rabbit model. J Orthop Res.2004;22:
221-7.22221
2004
[PubMed][CrossRef]
HammerDS, Rupp
S, Kreutz A, Pape D, Kohn D, Seil R. Extracorporeal shockwave therapy
(ESWT) in patients with chronic proximal plantar fasciitis. Foot
Ankle Int.2002;23:
309-13.23309
2002
HammerDS, Rupp
S, Ensslin S, Kohn D, Seil R. Extracorporeal shock wave therapy in
patients with tennis elbow and painful heel. Arch Orthop Trauma
Surg.2000;120:
304-7.120304
2000
[CrossRef]
KrischekO,
Rompe JD, Herbsthofer B, Nafe B. [Symptomatic low-energy shockwave therapy
in heel pain and radiologically detected plantar heel spur.] Z
Orthop Ihre Grenzgeb.1998;136: 169-74.
German.136169
1998
[CrossRef]
RompeJD,
Küllmer K, Riehle HM, Herbsthofer B, Eckardt A, Bürger R, Nafe B,
Eysel P. Effectivenss of low-energy extracorporal shock waves for chronic
plantar fasciitis. Foot Ankle Surg.1996;2:
215-21.2215
1996
[CrossRef]
SchõellnerC, Riedel C, Schwitalle M, Rompe JD, Heine J.
Shockwave treatment for plantar heel pain. In: Coombs R, Schaden W, Zhou SSH,
editors. Musculoskeletal shockwave therapy. London:
Greenwich Medical Media; 2000. p
53-9.53
2000
WangCJ, Chen
LM, Chen WS, Chen HS. Heel spurs. In: Coombs R, Schaden W, Zhou SSH,
editors. Musculoskeletal shockwave therapy. London:
Greenwich Medical Media; 2000. p
61-9.61
2000
PerlickL,
Boxberg W, Giebel G. [High energy shock wave treatment of the painful heel
spur.] Unfallchirurg.1998;101: 914-8.
German.101914
1998
[PubMed][CrossRef]
WangCJ, Chen
HS, Chen WS, Chen LM. Treatment of painful heels using extracorporeal
shock wave. J Formos Med Assoc.2000;99:
580-3.99580
2000
[PubMed]
MaierM,
Steinborn M, Schmitz C, Stabler A, Kohler S, Pfahler M, Dürr HR, Refior
HJ. Extracorporeal shock wave application for chronic plantar fasciitis
associated with heel spurs: prediction of outcome by magnetic resonance
imaging. J Rheumatol.2000;27:
2455-62.272455
2000
[PubMed]
BöddekerR, Schäfer H, Haake M. Extracorporeal
shockwave therapy (ESWT) in the treatment of plantar fasciitis—a
biometrical review. Clin Rheumatol.2001;20:
324-30.20324
2001
[PubMed][CrossRef]
RompeJD, Hopf
C, Nafe B, Bürger R. Low-energy extracorporeal shock wave therapy for
painful heel: a prospective controlled single-blind study. Arch
Orthop Trauma Surg.1996;115:
75-9.11575
1996
[CrossRef]
ChenHS, Chen
LM, Huang TW. Treatment of painful heel syndrome with shock waves.
Clin Orthop.2001;387:
41-6.38741
2001
[PubMed][CrossRef]
WangCJ, Chen
HS, Huang TW. Shockwave therapy for patients with plantar fasciitis: a
one-year follow-up study. Foot Ankle Int.2002;23:
204-7.23204
2002
[PubMed]
HammerDS, Adam
F, Kreutz A, Kohn D, Seil R. Extracorporeal shock wave therapy (ESWT) in
patients with chronic proximal plantar fasciitis: a 2-year follow-up.
Foot Ankle Int.2003;24:
823-8.24823
2003
[PubMed]
RompeJD,
Schoellner C, Nafe B. Evaluation of low-energy extracorporeal shock-wave
application for treatment of chronic plantar fasciitis. J Bone
Joint Surg Am.2002;84:
335-41.84335
2002
[CrossRef]
OgdenJA,
Alvarez R, Levitt R, Cross GL, Marlow M. Shock wave therapy for chronic
proximal plantar fasciitis. Clin Orthop.2001;387:
47-59.38747
2001
[PubMed][CrossRef]
OgdenJA,
Alvarez RG, Marlow M. Shockwave therapy for chronic proximal plantar
fasciitis: a meta-analysis. Foot Ankle Int.2002;23:
301-8.23301
2002
[PubMed]
BuchM, Knorr
U, Fleming L, Theodore G, Amendola A, Bachmann C, Zingas C, Siebert WE.
[Extracorporeal shockwave therapy in symptomatic heel spurs. An overview.]
Orthopäde.2002;31: 637-44.
German.31637
2002
[PubMed][CrossRef]
RompeJD,
Decking J, Schoellner C, Nafe B. Shock wave application for chronic
plantar fasciitis in running athletes. A prospective, randomized,
placebo-controlled trial. Am J Sports Med.2003;31:
268-75.31268
2003
[PubMed]
AbtT,
Hopfenmüller W, Mellerowicz H. [Shock wave therapy for recalcitrant
plantar fasciitis with heel spur: a prospective randomized placebo-controlled
double-blind study.] Z Orthop Ihre Grenzgeb.2002;140: 548-54.
German.140548
2002
[PubMed][CrossRef]
BuchbinderR,
Ptasznik R, Gordon J, Buchanan J, Prabaharan V, Forbes A.
Ultrasound-guided extracorporeal shock wave therapy for plantar fasciitis: a
randomized controlled trial. JAMA.2002;288:
1364-72.2881364
2002
[PubMed][CrossRef]
HaakeM, Buch
M, Schoellner C, Goebel F, Vogel M, Mueller I, Hausdorf J, Zamzow K,
Schade-Brittinger C, Mueller HH. Extracorporeal shock wave therapy for
plantar fasciitis: randomised controlled multicentre trial.
BMJ.2003;327:
75-9.32775
2003
[PubMed][CrossRef]
SpeedCA,
Nichols D, Wies J, Humphreys H, Richards C, Burnet S, Hazleman BL.
Extracorporeal shock wave therapy for plantar fasciitis. A double blind
randomised controlled trial. J Orthop Res.2003;21:
937-40.21937
2003
[PubMed][CrossRef]
AlvarezR.
Preliminary results on the safety and efficacy of the OssaTron for treatment
of plantar fasciitis. Foot Ankle Int.2002;23:
197-203.23197
2002
[PubMed]
HenneyJE.
From the Food and Drug Administration: shock wave for heel pain.
JAMA.2000;284:
2711.2842711
2000
[CrossRef]
AtkinsCJ,
Zielinski A, Makosinski A. Palpometry: a novel concept in pain
measurement. Nat Med.1995;1:
1138-9.11138
1995
[PubMed][CrossRef]
BendtsenL,
Jensen R, Jensen NK, Olesen J. Muscle palpation with controlled finger
pressure: new equipment for the study of tender myofascial tissues.
Pain.1994;59:
235-9.59235
1994
[PubMed][CrossRef]
Bell-KrotoskiJA, Fess EE, Figarola JH, Hiltz D. Threshold
detection and Semmes-Weinstein monofilaments. J Hand
Ther.1995;8:
155-62.8155
1995
McGillM,
Molyneaux L, Yue DK. Use of the Semmes-Weinstein 5.07/10 gram
monofilament: the long and the short of it. Diabet
Med.1998;15:
615-7.15615
1998
[CrossRef]
YongR, Karas
TJ, Smith KD, Petrov O. The durability of the Semmes-Weinstein 5.07
monofilament. J Foot Ankle Surg.2000;39:
34-8.3934
2000
[PubMed][CrossRef]
WareJE Jr,
Snow KK, Kosinski M, Gandek KB.SF-36 health survey. Manual and
interpretation guide. Boston: The Health Institute, New England
Medical Center; 1993.
1993
OgdenJA,
Toth-Kischkat A, Schultheiss R. Principles of shock wave therapy.
Clin Orthop.2001;387:
8-17.3878
2001
[PubMed][CrossRef]
RolesNC,
Maudsley RH. Radial tunnel syndrome: resistant tennis elbow as a nerve
entrapment. J Bone Joint Surg Br.1972;54:
499-508.54499
1972
[PubMed]
LeeGP, Ogden
JA, Cross GL. Effect of extracorporeal shock waves on calcaneal bone
spurs. Foot Ankle Int.2003;24:
927-30.24927
2003
[PubMed]
CrawfordF,
Atkins D, Edwards J. Interventions for treating plantar heel pain.
Cochrane Database Syst Rev.2000;3:
CD000416.3CD000416
2000
[PubMed]
MartinRL,
Irrgang JJ, Conti SF. Outcome study of subjects with insertional plantar
fasciitis. Foot Ankle Int.1998;19:
803-11.19803
1998
[PubMed]
WeilLS Jr,
Roukis TS, Weil LS, Borrelli AH. Extracorporeal shock wave therapy for the
treatment of chronic plantar fasciitis: indications, protocol, intermediate
results, and a comparison of results to fasciotomy. J Foot Ankle
Surg.2002;41:
166-72.41166
2002
[CrossRef]
FuselierHA,
Prats L, Fontenot C, Gauthier A Jr. Comparison of mobile lithotripters at
one institution: healthtronics lithotron, Dornier MFL-5000, and Dornier Doli.
J Endourol.1999;13:
539-42.13539
1999
[PubMed][CrossRef]
OgdenJA, Cross
GL, Williams SS. Bilateral chronic proximal plantar fasciopathy: treatment
with electrohydraulic orthotripsy. Foot Ankle Int.2004;25:
298-302.25298
2004
[PubMed]