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REGISTERED REPORT PROTOCOL
Comparison of the effect of hyaluronic acid
injection versus extracorporeal shockwave
therapy on chronic plantar fasciitis: Protocol
for a randomized controlled trial
Gabriel Ferraz FerreiraID
1☯
*, Davy Sevilla
2‡
, Carolinne Nascimento Oliveira
2‡
, Luiz Carlos
Nogueira Junior
2‡
, Gustavo Gonc¸alves Arliani
3‡
, Victor Ota
´vio Oliveira
3‡
, Miguel
Viana Pereira Filho
4☯
1Foot and Ankle Surgery Group, Orthopaedics and Traumatology Unit, Prevent Senior, São Paulo, Brazil,
2Department of Orthopaedics and Traumatology, Prevent Senior, São Paulo, Brazil, 3Head of Department,
Orthopaedics and Traumatology Unit, Prevent Senior, São Paulo, Brazil, 4Head of Foot and Ankle Surgery
Group, Orthopaedics and Traumatology Unit, Prevent Senior, São Paulo, Brazil
☯These authors contributed equally to this work.
‡ These authors also contributed equally to this work
*gabriel.ferraz38@yahoo.com.br
Abstract
Background
Plantar fasciitis is the most common cause of pain in the plantar region of the heel, and
extracorporeal shockwave therapy (ESWT) is an option used in cases where conservative
treatment fails. Hyaluronic acid (HA), initially used for osteoarthrosis, is a treatment option
because it has been applied to extra-articular regions, such as tendons, ligaments, and fas-
cia. The aim of the present study will be to evaluate the outcomes of pain, function, and per-
sonal satisfaction after a single injection of HA and to compare the results with those of
ESWT in patients with chronic plantar fasciitis.
Methods
The study will include 80 patients who will be randomized to receive three sessions of ESWT
(n = 40) or a single ultrasound-guided HA injection in the plantar fascia (n = 40). The out-
comes will include the visual analog pain scale score, American Orthopaedic Foot and Ankle
Society (AOFAS) score, and Foot and Ankle Outcome Score (FAOS). All of the assessments
will be performed at baseline and 3, 6, and 12 months after treatment. Statistical analysis will
be performed using the repeated measures ANOVA (analysis of variance test) for primary
and secondary outcomes and also Fisher’s Least Significant Difference, a Post-Hoc test. We
will use R software for statistical analysis, randomization, and sample size calculation.
Results
Recruitment and data collection will begin in November 2020, with completion scheduled for
November 2022 and final publication available in March 2023.
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This is a Registered Report and may have
an associated publication; please check the
article page on the journal site for any
related articles.
OPEN ACCESS
Citation: Ferreira GF, Sevilla D, Oliveira CN, Junior
LCN, Arliani GG, Oliveira VO, et al. (2021)
Comparison of the effect of hyaluronic acid
injection versus extracorporeal shockwave therapy
on chronic plantar fasciitis: Protocol for a
randomized controlled trial. PLoS ONE 16(6):
e0250768. https://doi.org/10.1371/journal.
pone.0250768
Editor: Walid Kamal Abdelbasset, Prince Sattam
Bin Abdulaziz University, College of Applied Medical
Sciences, SAUDI ARABIA
Received: September 3, 2020
Accepted: March 25, 2021
Published: June 24, 2021
Copyright: ©2021 Ferreira et al. This is an open
access article distributed under the terms of the
Creative Commons Attribution License, which
permits unrestricted use, distribution, and
reproduction in any medium, provided the original
author and source are credited.
Data Availability Statement: All relevant data from
this study will be made available upon study
completion.
Funding: The author(s) received no specific
funding for this work.
Conclusion
This trial will evaluate the effects of a single ultrasound-guided HA injection for the treatment
of chronic plantar fasciitis.
Trial registration
Brazilian Clinical Trials Registry (Register Number: RBR-97vkx4) http://www.ensaiosclinicos.
gov.br/rg/RBR-97vkx4/.
Introduction
Background
Plantar fasciitis is the most common cause of pain in the plantar region of the heel, especially
in middle-aged and elderly patients [1], and is often described as an overload of the plantar fas-
cia [2,3]. In most cases, plantar fasciitis is self-limiting, but the time for full resolution of symp-
toms can take up to one year, impairing the quality of life of patients and leading to frustration
among the healthcare team [4].
Several treatments have been described for plantar fasciitis, and the most commonly used
are noninvasive, such as nonsteroidal anti-inflammatory drugs, analgesics, night orthoses,
stretching, exercises, and insoles [5].
In cases of conservative treatment failure, some studies have shown benefits of corticoste-
roid injection, resulting in rapid improvement and ease of progression during rehabilitation
[6,7]. However, the use of corticosteroids can cause problems such as rupture of the plantar
fascia, infection, atrophy of the heel pad, and even changes in skin pigmentation [8–10].
Thus, extracorporeal shockwave therapy (ESWT) has emerged as an option for recalcitrant
cases of plantar fasciitis without improvement with conventional conservative treatment. This
modality showed satisfactory results in a placebo-controlled study [11] but was dependent on
the intensity, pulse cycle, and shockwave modality [12].
Meanwhile, due to successful treatment of knee arthrosis through hyaluronic acid (HA)
injection [13], the possibility of expanding its indication for regions such as the fascia and ten-
dons has arisen, and chronic plantar fasciitis is a possible candidate for this treatment due to
its anti-inflammatory and healing potential [14,15].
Study aim and hypotheses
The objective of the study is to compare the therapeutic efficacy of ultrasound-guided HA
application for chronic plantar fasciitis with that of ESWT. We suggest that recalcitrant plantar
fasciitis may benefit from the anti-inflammatory and healing properties of HA, thus accelerat-
ing the process of symptom improvement. The comparison will be with the ESWT because
there are several studies proving its benefit, representing an excellent control group.
Methods
Study design
This study is designed as a randomized, controlled, parallel groups, and intervention trial
(Fig 1).
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Competing interests: The authors have declared
that no competing interests exist.
Recruitment
The participants will be recruited during routine orthopedic outpatient care provided by
the authors at the Ana
´lia Franco and Bento Pires Unit of Prevent Senior, São Paulo, Brazil.
Recruitment will be continuous and sequenced in order to select a cohort of more heteroge-
neous patients in the study.
Fig 1. Research flow diagram.
https://doi.org/10.1371/journal.pone.0250768.g001
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Ethics
This protocol was approved by Scientific Research Committee of Instituto Prevent Senior
(Number 3,912,441–2020) and is registered on the Brazilian Clinical Trials Registry [16] (Reg-
ister Number: RBR-97vkx4). The authorization to use and disclose participant information is
restricted to this study, and the data will be kept for five years after publication.
Eligibility
The inclusion criteria are as follows: 1) clinical diagnosis of plantar fasciitis with failure of con-
servative treatment including stretching exercises, nonsteroidal anti-inflammatory drugs, anal-
gesics, and insoles for at least three months; 2) individuals of both genders who are older than
18 years and younger than 80 years; 3) the patient must be able to understand the informed
consent form; 4) visual analog pain scale (VAS) score greater than or equal to three points
(range from 0 to 10 points).
The exclusion criteria are patients with neuropathy, skin lesions, previous degenerative
lesions of the ankle, previous surgeries of the ankle or Achilles tendon, previous allergy to
sodium hyaluronate, or allergies to avian proteins, those less than 16 years of age, and patients
with sequelae of fractures of the tibial pilon, ankle, or foot. In addition, patients with collagen
disorders, rheumatoid arthritis, and seronegative arthritis will be excluded. Patients who are
not recommended to use shockwave therapy include the following: patients who use anticoag-
ulants, are pregnant, have a tumor in the treatment area, systemic infections or epilepsy.
Handling of data
The data management plan aims to synthesize high-quality data through standardized proce-
dures and thus, reduce errors and missing data that occur, generating an ideal database for
analysis.
Patient data will be collected in order to use numbers for personal identification (ID) and
managed using REDCap electronic data capture tools hosted at Instituto Prevent Senior
[17,18]. Full access to the final test data of the study will be granted only to selected
researchers.
REDCap (Research Electronic Data Capture) is a secure, web-based software platform
designed to support data capture for research studies, providing 1) an intuitive interface for
validated data capture; 2) audit trails for tracking data manipulation and export procedures; 3)
automated export procedures for seamless data downloads to common statistical packages;
and 4) procedures for data integration and interoperability with external sources. All data will
be available to the public in a data repository, without personal identification of the partici-
pants, after publication of the study.
Missing data
We consider minimal or no follow-up losses for the primary outcome. If more than 5% of the
missing data in the primary outcome is identified, we will perform a sensitivity analysis using
multiple imputations and estimation equation methods.
Sample size
The sample size was calculated using the pwr package of R software [19]. A study by Chew et al
[20] was used to determine the minimum change required in the treatment of chronic plantar
fasciitis with regard to the main outcome, which will consist of a change of 3.0 points in the
VAS between the baseline value and that at three months of follow-up after the intervention.
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The pooled standard deviation was set to 4.5 after examining preliminary values. Thus, we chose
a study power of 80% and type I error of 5%. The calculated sample size was 36 patients in each
group, but a sample size of 40 was specified to allow loss to follow-up during the study (10%).
Randomization
Participants (n = 80) who meet all eligibility criteria will be randomized at a 1:1 ratio to either
the HA intervention group or the control group (ESWT). Randomization will be performed in
blocks (random sizes of two, four, six, and eight) and used to ensure that the treatment groups
is balanced throughout the study period. This strategy ensures that the intervention group and
control group are balanced regarding the number of participants. To ensure allocation con-
cealment, random variation in block sizes (four to eight participants per block) will be used.
We will use the blockrand package of the R software to generate the randomization table.
Intervention
The interventions will be performed in the authors’ outpatient clinic and only after the partici-
pants sign the informed consent form and are allocated to one of the study arms.
The intervention with HA will be performed by the author (G.F.F.) through a single appli-
cation of Ostenil Plus
1
(2.0 mL with 40 mg of 2.0% sodium hyaluronate, TRB Chemedica,
Munich, Germany). This product is indicated for extra-articular regions, as indicated in the
package insert: “It is also indicated in cases of pain and mobility restriction due to inflamma-
tion and degeneration in tendons, tendon sheaths, and entheses.” This product contains low-
molecular-weight HA. The injection will be guided in all cases by a portable ultrasound Butter-
fly iQ
1
device (Butterfly Network, New York, USA) to increase the precision and efficacy of
the intervention.
The ESWT intervention (radial type) will be performed by the author (L.C.N.J.) in three ses-
sions in total, one per week, using a Swiss DolorClast Master
1
device (Electro Medical System,
Nyon, Switzerland). Patients will be subjected to 2,500 focused shockwaves with an energy flux
density of 0.05 mJ/mm
2
and a frequency of 8 Hz. Each session will last approximately 15 min.
The treatment will follow that recommended by the generator’s distribution company.
After the interventions, participants will be recommended to perform daily posterior chain
stretching exercises while remaining under follow-up with the physical therapy team. The use
of oral analgesics will be prescribed and authorized.
Regarding the risks of the interventions, local injection of HA may cause adverse effects
such as pain, sensation of heat, redness, and edema, as described in the package insert. Shock-
wave therapy may cause an inflammatory process and local pain, but these symptoms are usu-
ally quickly resolved with mild analgesics.
Measures
Clinical evaluation using pain, function, and personal satisfaction scores will be performed for
a period of one year in the following intervals after the interventions: three, six, and 12 months.
Thus, we will be able to evaluate the results in the short, medium, and long term. The authors
(X.X.X.X., X.X.X.) will blindly evaluate the participants regarding the intervention performed.
Outcome measures
The primary outcome to be evaluated will be the VAS. The questionnaire will be administered
at baseline and three, six, and 12 months after the intervention during routine visits previously
scheduled with the researchers.
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The secondary outcomes to be evaluated will be function and personal satisfaction. The for-
mer will be assessed based on the American Orthopaedic Foot and Ankle Society (AOFAS)
score [21] for the ankle and hindfoot and the Foot and Ankle Outcome Score (FAOS) [22].
The latter will be evaluated based on the personal satisfaction criteria published by Roles and
Maudsley [23].
Statistical analysis
Statistical analysis will be conducted primarily through an intention-to-treat analysis of all
patients, in both arms, except for lost cases or withdrawal of informed consent. In addition, a
per–protocol analysis will be conducted.
All analysis will be performed using the statistics package of R software [19]. We will use
the repeated measures ANOVA (analysis of variance test) for the primary and secondary out-
comes and also the Fisher’s Least Significant Difference, a Post-Hoc test.
Continuous variables will be measured using descriptive statistics, including the mean and
standard deviation, and tested for the normality of their distribution using the Shapiro test
[24]. Categorical variables will be presented according to their proportion and confidence
interval.
Results
Recruitment and data collection started in November 2020. We estimate that data collection
should be completed in June 2022, and the results should be available in November 2022.
Discussion
Overview
The present study will be unprecedented in terms of the inclusion of HA injection for the
treatment of chronic plantar fasciitis in a randomized clinical trial. We believe that use of
shockwave therapy in the control group can serve as a reliable parameter in comparing the
results.
The possibility of comparing the results with those of corticosteroid injection seems to be
the most rational, but the published results on complications related to rupture and injury of
the plantar fascia contributed to the decision to not include this type of intervention in the
study design [8–10].
We also chose not to include placebo therapies such as anesthetic infiltration or needling
because shockwave therapy has shown satisfactory results and thus can be used as a control.
The use of HA in the study group is justified because it is a new procedure for treatment of
chronic plantar fasciitis, with only one case series showing benefits with its use [14].
In addition, HA has been increasingly used in the treatment of tendinopathies and extra-
articular inflammation [25–27]. Other types of interventions, such as botulinum toxin injec-
tion, were excluded based on previously published results [28].
The described effects of HA include local lubrication [29], promoting tissue healing in the
region between bone and tendon [30], and tissue regeneration [31]. Another important func-
tion reported is to decrease the sensitivity of regional sensory nerves, with decreasing pain
[32].
The ESWT intervention produce an effect that is considered direct and other indirect on
the treated region. The indirect effect is the production of localized cavity bubbles. The direct
effect is the transmission of energy from the equipment to the target tissue. Both produce a
local biological response [33].
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This protocol describes a study focused on the application of a new treatment method to
combat chronic plantar fasciitis. The results of this study will have important implications for
the prescription of HA as a therapeutic option, showing whether clinical improvement occurs
and comparing the results with those of an effective treatment method.
Strengths and limitations of this study
The strengths of the study are as follows: 1) new treatment method; 2) appropriate methodo-
logical design; 3) previous publication of the protocol, thus minimizing publication bias; and
4) single-center study using the same technique, interventions, and evaluators. We believe that
the main limitations of the study are the short follow-up duration and that the mean age of
patients will be greater than that of the general population (our center specializes in elderly
patients).
Conclusions
This trial will evaluate the effects of a single ultrasound-guided hyaluronic acid injection for
the treatment of chronic plantar fasciitis. The control group will receive an intervention using
shockwave therapy, which has been shown to be effective in several previously published
studies.
Supporting information
S1 Checklist.
(DOC)
S1 File. Ethics committee portuguese.
(PDF)
S2 File. Ethics committee english.
(PDF)
S3 File. Correction ethics committee portuguese.
(PDF)
S4 File. Correction ethics committee english.
(PDF)
S5 File. Complete project approved in portuguese.
(PDF)
S6 File. Complete project approved in english.
(PDF)
Author Contributions
Conceptualization: Gabriel Ferraz Ferreira, Davy Sevilla, Carolinne Nascimento Oliveira,
Gustavo Gonc¸alves Arliani, Victor Ota
´vio Oliveira, Miguel Viana Pereira Filho.
Data curation: Gabriel Ferraz Ferreira, Davy Sevilla, Gustavo Gonc¸alves Arliani, Victor Ota
´-
vio Oliveira, Miguel Viana Pereira Filho.
Formal analysis: Gabriel Ferraz Ferreira, Carolinne Nascimento Oliveira, Gustavo Gonc¸alves
Arliani, Miguel Viana Pereira Filho.
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Funding acquisition: Gabriel Ferraz Ferreira, Luiz Carlos Nogueira Junior, Miguel Viana Per-
eira Filho.
Investigation: Gabriel Ferraz Ferreira, Luiz Carlos Nogueira Junior, Miguel Viana Pereira
Filho.
Methodology: Gabriel Ferraz Ferreira, Davy Sevilla, Luiz Carlos Nogueira Junior, Gustavo
Gonc¸alves Arliani, Miguel Viana Pereira Filho.
Project administration: Gabriel Ferraz Ferreira, Carolinne Nascimento Oliveira, Miguel
Viana Pereira Filho.
Resources: Gabriel Ferraz Ferreira, Miguel Viana Pereira Filho.
Software: Gabriel Ferraz Ferreira, Davy Sevilla, Miguel Viana Pereira Filho.
Supervision: Davy Sevilla, Miguel Viana Pereira Filho.
Validation: Davy Sevilla, Carolinne Nascimento Oliveira, Miguel Viana Pereira Filho.
Visualization: Gabriel Ferraz Ferreira, Carolinne Nascimento Oliveira, Miguel Viana Pereira
Filho.
Writing – original draft: Gabriel Ferraz Ferreira, Davy Sevilla, Carolinne Nascimento Oli-
veira, Luiz Carlos Nogueira Junior, Gustavo Gonc¸alves Arliani, Victor Ota
´vio Oliveira,
Miguel Viana Pereira Filho.
Writing – review & editing: Gabriel Ferraz Ferreira, Davy Sevilla, Carolinne Nascimento Oli-
veira, Luiz Carlos Nogueira Junior, Gustavo Gonc¸alves Arliani, Victor Ota
´vio Oliveira,
Miguel Viana Pereira Filho.
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