Clinical Effects of the Intralesional Application of Incobotulinum Toxin vs Corticosteroid in Patients With Plantar Fascitis
Phase: PHASE1
Conditions: Plantar Fasciitis of Both Feet, Pain, Function
Sponsor: Instituto Mexicano del Seguro Social

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Clinical Effects Of The Intralesional Application Of Incobotulinum 
Toxin vs Corticosteroid In Patients With Plantar Fascitis . 
 
NCT ID not yet assigned] 
MERIDA, YUCATAN, MEXICO 
JANUARY 2025 

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I Summary 
 
Theoretical Framework: Plantar fasciitis (PF) is one of the most common 
pathologies of plantar pain, with relevance due to its location and symptoms, as it 
makes it difficult for the individual to carry out daily, work and recreational tasks. Its 
treatment is multiple, which has been widely discussed. There is little evidence on 
treatment with botulinum toxin ( BoNT ) and steroids in the short and medium term, 
on their superiority between them and on other techniques. Both are efficient 
analgesics and anti-inflammatories , however there is no standardization of their use. 
 
Objectives: To evaluate the clinical effects of intralesional application of 
incobotulinum toxin vs corticosteroid in patients with plantar fasciitis . 
 
Material and methods: Prospective, experimental, randomized, controlled clinical 
study; the population will be recruited in the outpatient clinic of the rehabilitation 
service meeting the inclusion criteria, two randomized study groups will be formed: 
GROUP A: Patients who accept intralesional infiltration with incobotulinum toxin . 
GROUP B: Patients who accept intralesional infiltration with dexamethasone. 
Both groups will be assessed before application, at 1 month, at 2 and 4 
months post intervention. The visual analogue scale (VAS), the American 
Orthopaedic Foot and Ankle Society (AOFAS) scale and the Foot and Ankle 
Disability Index (FADI) will be used to assess pain, foot functionality, functional 
disability index in activities of daily living, in physical activity and measurement of the 
dorsiflexion arch in 2 visits at the beginning of diagnosis and at 4 months, collecting 
the variables and establishing a hypothesis analysis to accept or discard normality 
criteria of the same with tendency and its significance in relation to p <0.05 to 
establish contrast of the results with parametric or non-parametric variables 
according to whether or not the hypothesis of normality is discarded. 

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II Background 
PF is defined as a degenerative and inflammatory process resulting from 
excessive loading of the plantar fascia due to repetitive tension, causing micro-tears 
of the same, generating tissue granulation, collagen disorganization and 
inflammation. Its main function is to prevent the collapse of the longitudinal arch of 
the foot and assist propulsion in the gait cycle (1,2,3). 
 
Study protocols have been revealed worldwide for its effective treatment by 
means of infiltrations (with few studies reported in Mexico) showing different injection 
techniques of the plantar fascia including superficial, deep and intrafascial injections 
, the latter being the most commonly used technique. However, the evidence shows 
that to date there is no definitive consensus on the most appropriate technique for 
FP injection( 4). 
 
RISK FACTORS 
Among the main risk factors are female sex, people aged 40 to 60 years, 
anatomical alterations such as heel spurs, flat feet, hollow feet, work activities with 
weight loads such as walking or prolonged standing. In the non-athletic population, 
there is an increase in the body mass index > 27 kg/m2, kinematic alterations such 
as decreased range of dorsiflexion movement (since it causes overpronation of the 
foot and places a greater load on the fascia), sedentary lifestyle, while in the athletic 
population there is a higher risk in runners and military personnel because it 
increases the elastic cycle of stretching-shortening causing injuries and generating 
microtraumas in the fascia (5,6). 
 
EPIDEMIOLOGY: 
The exact incidence and prevalence of PF is unknown, but estimates show 
that approximately 1 million annual patient visits are due to plantar fasciitis (6). It 
affects 1 in 10 people at some point in their life, representing 15% of medical 
consultations for foot pain. In Mexico, 30% of the population suffers from it according 
to the Ministry of Health. 

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PF occurs at any age but is described with a higher incidence at 40 to 60 
years of age, having a greater predilection for females than males, ratio 2:1. Plantar 
fasciitis is associated with a variety of sports, but is mainly reported in runners, 
gymnasts, and basketball players (incidence of 5% to 10%) (5,7). 
 
ETIOLOGY: 
It is considered multifactorial, which is why multiple therapeutic options have 
been analyzed. The different treatment modalities can be classified into noninvasive 
and invasive therapies (8). 
 
PATHOPHYSIOLOGY: 
The PF from its origin in the calcaneal tuberosity , extends distally and inserts 
into the MTP joints and each proximal phalanx of the toes. Functionally it is divided 
into 3 contiguous bands or bundles: medial, central and lateral, the largest being the 
central portion. The heel absorbs 110% of body weight when landing on the heel 
and up to 200% when running. The PF acts as a shock absorber, but its elongation 
capacity is limited since after 40 years of age , the fat begins to atrophy, with loss of 
water, collagen and elastic tissue, and the resulting loss of shock absorption in the 
heel (1). 
Therefore, these findings support that PF is a biomechanical overuse 
condition resulting in degenerative changes at its attachment to the calcaneus 
originating inflammatory data initially with subsequent degeneration (7). 
It is considered a disorder self-limiting , since in 80-90% of cases the 
symptoms disappear within 10 months. However, this time interval is frustrating for 
both the patient and the specialist (9). 
 
CLINICAL PICTURE: 
Patients with PF typically present with acute pain, a feeling of stiffness that is 
exacerbated by the first steps in the morning, long periods of standing or sitting. The 
pain often decreases with ambulation or the beginning of an athletic activity, but then 

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increases throughout the day as activity increases. In some patients, gait 
disturbances may occur, creating an antalgic pattern or limp (6). 
 
PHYSICAL EXAMINATION: 
In the physical examination, we can identify anatomical alterations such as 
flat feet, hollow feet (predisposing to risk factors), signs of atrophy of the fat pad, and 
gait alterations with anti-pain patterns. Palpation of painful points should be 
performed, usually reproduced in the medial plantar calcaneal tubercle and the path 
of its three bands. Passive dorsiflexion of the foot and toes can reproduce the pain. 
The windlass test specifically involves the active reproduction of pain through 
passive dorsiflexion of the first metatarsophalangeal joint, and is positive if pain is 
provoked. Pain can also be checked by keeping the patient on tiptoe or heel, that is, 
performing maneuvers to tighten the plantar fascia. (1,6). 
 
DIAGNOSIS: 
 
Diagnosis is made through careful questioning and clinical signs found during 
examination. 
Diagnostic aids such as imaging studies (radiographs or ultrasound 
evaluation) are also described, but are not routinely used. Plain radiographs may 
show soft tissue calcifications or heel spurs (not pathognomonic for PF) on the 
underside of the heel and to rule out other pathologies, while ultrasound is 
inexpensive and useful to rule out soft tissue pathology of the heel and measure 
fascial thickness (>4.0 mm and increasing intensity). Magnetic resonance imaging 
is often expensive, used to evaluate repetitive causes of pain determined by the 
finding of thickening of the plantar fascia with increased signal intensity on T2 
weighting (6). 
 
DIFFERENTIAL DIAGNOSES: 
Differential diagnoses are grouped according to their etiology into 
neurological, skeletal and soft tissue causes, the most common being soft tissue 

6 
 
causes. It is important to identify these causes because the therapeutic approach is 
different (see table 1). 
Diagnósticos diferenciales del dolor plantar del talón (7). 
Etiología 
Síntomas 
Causas Neurológicas 
Neuritis de Baxter 
Ardor en la parte medial del talón. 
Atrapamiento del nervio 
calcáneo medial 
Ardor sobre la cara inferomedial del calcáneo. 
Síndrome del túnel tarsiano 
Parestesia en el tobillo medial que irradia a la cara 
plantar del pie. 
Causas Esqueléticas 
Fractura aguda de calcáneo 
Incapacidad para soportar peso, secundaria a un 
impacto de alta energía. 
Tumor óseo 
Dolor óseo profundo de predominio nocturno. 
Apofisitis calcánea 
Dolor en el talón en niñas de 8 a 13 años o niños de 
10 a 15 años. 
Fractura por estrés del 
calcáneo 
Dolor en el talón de aparición lenta secundario a 
cargas repetitivas. 
Espondiloartropatías 
Dolor en el talón en la inserción del tendón de Aquiles. 
Causas en tejidos blandos 
Tendinitis de Aquiles 
Dolor en cara posterior del tobillo a nivel del maléolo 
medial. 
Tenosinovitis del flexor largo 
del dedo gordo 
Dolor con flexión resistida del dedo gordo. 
Rotura de la fascia plantar 
Un chasquido o crujido al despegar el pie del suelo o 
de hacerlo girar seguido de dolor repentino intenso. 
Fibroma plantar 
Nódulo en la superficie plantar de la porción media del 
pie. 
Tendinitis tibial posterior 
Dolor con resistencia a la inversión del pie. 
TREATMENT: 
Treatment can be divided into non-surgical and surgical. Non-surgical 
treatment includes the following: 
For initial treatment, the American College of Foot and Ankle Surgeons 
(ACEFAS) recommends tailoring treatment to the patient's symptoms, lifestyle, and 
activity level because most treatment modalities are not supported by sufficient 
evidence, including stretching , since previously, protocols emphasized stretching of 
the Achilles tendon because of the lack of ankle dorsiflexion. However, studies have 
indicated that specific stretching of the plantar fascia may be more beneficial than 
simple muscle strengthening (6). Regarding the use of foot orthoses, a recent 
systematic review and meta -analysis of 19 studies found very low quality evidence 
for short-term pain reduction or long-term function as was thought due to its function 
of reducing fascial tension by providing support and reducing foot pronation (6,10). 
Regarding bandaging or taping , some studies mention that it helps to fix the 
axis of the subtalar joint , reduces excessive pronation and corrects foot disorders, 
however in a study of 5 controlled trials by Van de Water et al. from 2010, it 

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demonstrated a decrease in pain in one week, but after this, its effectiveness in 
reducing pain and improving function is reduced (11). 
For dry needling, which consists of inserting a fine needle into a myofascial 
trigger point, decreasing pain by altering the biochemical environment and local 
blood flow, a meta-analysis by Chunhui He et al. in 2017 showed that it reduces pain 
in patients with PF, however, it was limited by the inclusion of different techniques 
and lower quality studies, while ACEFAS does not recommend being for or against 
this treatment ( 12,13). For the purpose of keeping the ankle in a neutral position 
during sleep to prevent triceps surae contractures, the use of night splints is found, 
however in a prospective randomized study of 116 patients by A Probe et al. 
mentions that no statistical differences were observed with the presence or absence 
of a night splint (14,15). 
Another useful treatment in PF is extracorporeal shock wave therapy (ESWT) 
which was first developed in 1990 and is intended to produce vibrations to form 
neovascularization, increase growth factors and destroy unmyelinated nerve fibers. 
Currently there is no consensus on the optimal intensity, pulse or modality of the 
shock wave (6). In a randomized controlled trial of 166 patients by Rachelle 
Buchbinder et al. in 2002 showed in 166 patients randomized to placebo and 
ultrasound-guided ESWT that both groups had improvement in heel pain, but there 
was no benefit at the end of treatment (16). 
Regarding the objective treatment of our study, infiltrations are found, 
including corticosteroids, which are used to reduce pain and inflammation. Some 
authors have considered it beneficial, as in the meta-analysis by Zonghuan Li et al. 
in 2014 where he assigned 2 groups of 83 patients with PF, in the first with the 
ultrasound-guided application of saline solution and in the other group with 
dexamethasone. The latter had better pain relief at 4 weeks and decreased PF 
inflammation at 3 months compared to the saline solution group (17). However, 
complications such as fat pad atrophy and fascia rupture have been described in 
2.4% of patients receiving this type of treatment (6). 

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BoNT has been used to treat many chronic pain conditions and has recently 
been used in some studies to treat PF. Its mechanisms of action include inhibition of 
pain peptides from nerve terminals and sensory ganglia, anti-inflammatory, 
antiglutaminergic effects, and reduction of sympathetic neural discharge. Some 
studies such as the only one reported in Mexico, in Monterrey Nuevo León by 
Elizondo- Rodriguez et al in 2013 , prospective, experimental, randomized, double- 
blind and controlled clinical trial in 36 patients demonstrated the superior effect in 
the use of toxin by dividing into 2 groups: group A infiltration with toxin (100 IU in 
each gastrocnemius and 50 IU in soleus), group B infiltration with dexamethasone 
(2ml diluted in 2ml of 2% lidocaine in fascia insertion) + stretching exercises in both 
groups, which were evaluated in 6 visits (at the time of diagnosis, at 1, 2, 4 and 6 
months post infiltration) and EVA, AOFAS, FADI and Maryland scales were applied, 
finding no statistically significant difference in the EVA scale between the 2 groups 
in the first and second visit, until the third visit improvement was shown in the toxin 
group as well as in the scale of AOFAS and Maryland improved from the 2nd visit. 
For the FADI, it was similar at the first visit between the 2 groups and during the 
second visit until the sixth visit it was significant for the toxin group (17). 
In the randomized study by Ruiz-Hernández et al. in 2023 in Spain of 59 
patients where pain and functionality were evaluated in 4 visits (at the time of 
diagnosis, the first, third, sixth and twelfth month post infiltration) using the EVA, 
AOFAS and FAAM scales of 3 groups: group 1 platelet-rich plasma (PRP) infiltration, 
group 2 toxin infiltration (application in medial gastrocnemius 100 IU and lateral 50 
IU and in fascia insertion 50 IU) and group 3 control (mobilizations and stretching). 
They reported a progressive improvement in pain at 1 month with significant data on 
the EVA in the BoNT and PRP group, while in the control group improvement was 
shown after 3 months. The fresh plasma and toxin groups showed improvement on 
the AOFAS scale at the first month and persisting over time, while in the control 
group it was observed after 3 months. However, in the toxin group at 12 months 
there was a slight but non-significant worsening compared to 6 months suggesting 
that it was due to the loss of effect over time. For the functional improvement of the 
FAAM scale, it was observed from 3 months onwards and was maintained until 12 

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months for the toxin and PRP, the latter being superior, but without significant 
difference. No adverse effects were reported, concluding that the toxin is superior 
for short-term treatment while plasma was superior in the long term and for 
conservative treatment it provides a late improvement for pain relief. Regarding 
epidemiology, the predominance of the female sex was shown at 70% and in 
overweight patients (3). 
In another prospective, randomized, controlled study by Tannaz-Ahadi in 
2022 in Iran where the efficacy of ultrasound-guided infiltration of toxin ( 100 IU flexor 
digitorum brevis and 50 IU plantar square diluted in 1.5 ml of saline) vs corticosteroid 
( intralesional in FP insertion 1ml of corticosteroid diluted in 1ml of 0.9% saline) and 
stretching exercises for triceps surae and gastrocnemius in 35 patients with a clinical 
diagnosis of FP between 18 and 65 years of age , who were evaluated using the 
EVA and FAAM scales on 3 occasions, at the time of diagnosis (before the 
intervention), at 3 weeks, 12 weeks, and 6 months. It was found that in both groups 
pain and functionality improved after 3 weeks post infiltration . In the toxin group, the 
EVA and FAAM improved at 3 and 12 weeks, except at 6 months, compared to the 
corticosteroid group. It was concluded that the effects of the toxin last longer than 
those of corticosteroids combined with stretching exercises (4). 
Surgical treatment is considered when non-surgical treatments have failed. 
The preferred surgical method is open, percutaneous or endoscopic plantar 
fasciotomy without inferior calcaneal exostectomy . Possible complications include 
collapse of the plantar arch and scarring of the incision site (18). 
 
INCOBOTULINUMTOXIN-A TOXIN (INSTITUTIONAL CODE:0100043620101) 
 
BoNT is produced by Clostridium botulinum toxin, a rod-shaped, spore- 
forming, anaerobic Gram-positive bacterium. The therapeutic application of 
botulinum toxin began more than two centuries ago, by the German physician 
Justinus Kerner , who suggested the supposed clinical utility of a toxin extracted 
from spoiled sausages ( botulus , Latin for sausage), which had caused several fatal 
outbreaks in the kingdom of Württemberg in the late 18th and early 19th centuries. 

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However, the first documented therapeutic application was in 1977, when Dr. Alan 
B. Scott injected a purified botulinum toxin into the extraocular muscles to treat 
strabismus. 
BoNT was first approved by the US FDA in 1989. There are currently seven 
different toxins (A, B, C, D, E, F, and G), but only toxins A and B are currently used 
for medical purposes. Both have similar effects, although there are slight differences 
in the mechanism of action. In terms of potency, type A ranks first, followed by type 
(19). 
 
MECHANISM OF ACTION: 
BoNT inhibits the release of acetylcholine from presynaptic vesicles at 
neuromuscular junctions, resulting in flaccid paralysis in peripheral skeletal 
musculature and autonomic nerve terminals. Once BoNT enters the bloodstream, its 
heavy chain is recognized by receptors on the presynaptic membrane and then 
taken up by endocytosis. The disulfide bridge is subsequently broken and the light 
chain is released into the cytosol. The light chain cleaves soluble N -ethylmaleimide- 
sensitive fusion protein-binding protein receptor proteins and thereby inhibits 
neurotransmitter release into synaptic vesicles. 
Chronic inflammation in soft tissues is associated with hyperexcitability of 
spinal nociceptive neurons (central sensitization). Botulinum toxin A can counteract 
and inhibit these peripheral and central sensitization processes, thereby modulating 
the pain resulting from PF. Botulinum toxin A administration has been shown to 
inhibit substance P release from dorsal root ganglion neurons and stimulated 
calcitonin gene (CGRP) release from trigeminal ganglion neurons. Studies have also 
shown that botulinum toxin A can reduce the expression of proinflammatory 
cytokines such as IL-1b, IL-6, and TNF-a, dampening the inflammatory process and 
reducing the spread of pain resulting from peripheral stimuli. These reductions in 
peripheral sensitization and afferent input to the spinal cord from peripheral nerve 
endings may indirectly decrease the central sensitization process. Botulinum toxin A 
can also be transported along the axon in a retrograde manner and modulate 
neuronal activity in the central nervous system through stimulation of inhibitory 

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gamma-aminobutyric acid (GABA)-A receptors and m-opioid receptors in the spinal 
cord. All these properties of botulinum toxin A may explain why administration of this 
toxin can reduce pain in patients with PF (19). 
BoNT has a prolonged biological effect in which its therapeutic effect 
increases (accumulation phase), remains at a plateau for 6 to 10 weeks (plateau 
phase), and then gradually decreases (wearing off phase) . Exact data on the 
duration of action of BoNT in humans is scarce, however some studies report that it 
remains within the range of three to six months, up to one year, with serotype A toxin 
being reported to have a longer duration compared to the others (20, 22). 
 
PREPARATION METHOD 
 
 
According to the bibliography of various authors, different types of dilutions 
have been used for 100 IU of Incobotulinum ; however, the preparation in 1 ml of 
0.9% physiological solution has been the most used for infiltration in FP (19,20). 
 
INDICATIONS AND RECOMMENDATIONS: 
 
 
According to the FDA, some other authorized indications for the use of BoNT 
are: expression lines on the face, blepharospasm , hemifacial spasm , strabismus, 
cervical dystonia , migraine, spasticity in upper and lower extremities, detrusor 
overactivity , sialorrhea, among others. Currently, it covers around 26 indications in 
about 6 medical specialties and other indications are being investigated (21). 
The maximum dose used is much lower than the lethal dose (3000 U in 
monkeys). Originally, it was also recommended that total doses of BoNT should not 
exceed about 400 IU per injection series to reduce the risks of antibody formation, 
however in the study by Dressler et al. 2015 it was shown that, when necessary, 
total doses of BoNT can exceed 400 IU without risks of antibody formation and 
systemic adverse effects (21,22). 
BoNT concentration and dose may play important roles in the therapeutic and 
non-therapeutic effects of individual formulations. Incobotulinum with molecular 

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weight of 150 kD has its own advantages over other formulations. For example, it 
does not require refrigeration and contains negligible amounts of albumin (protein 
load of 0.44 ng/100 units). Therefore, the theoretical risk of antibody production 
against the toxin is lower than other formulations (19). 
Currently there is no standardized dose of toxins for the treatment of FP (21). 
The adverse effect profile of BoNT is remarkably benign, as BoNT remains at 
its injection site and does not participate in the body's overall metabolism, thus 
sparing critical elements to organs of absorption and secretion. Local adverse effects 
are caused when BoNT spreads from the target tissue to adjacent tissues. Systemic 
adverse effects occur when relevant amounts of BoNT are distributed with the 
bloodstream. (22) 
 
INTERACTIONS 
 
 
Some studies warn against BoNT therapy in the presence of anticoagulation. 
However, it has recently been shown that BoNT therapy can be performed safely 
provided that fine injection needles are used. In case of unusual, hitherto undetected 
underlying hypersensitivity to BoNT therapy , neuromuscular transmission disorders 
should be considered (22). 
 
III Justification 
 
 
FP is one of the most frequent pathologies of plantar heel pain with greater 
relevance because due to its location and symptoms it makes walking and the 
performance of daily or everyday tasks that necessarily involve performing a support 
and push phase with the foot difficult, thus decreasing the individual's physical, work 
and recreational capacity. If not treated properly, it can evolve and affect the 
functional capacity of people, increasing days of absenteeism and generating a 
greater demand for medical consultation and treatment services. In addition, FP may 
require invasive and expensive surgical procedures, such as fasciotomy, which are 
not accessible to all patients and can generate comorbidities and disabilities. 

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Therefore, the search for non-surgical therapeutic alternatives, such as the use of 
intralesional medications , is essential to improve the management of this pathology. 
 
Although the studies published to date have not yet standardized the use of 
botulinum toxin or corticosteroids, they have shown a significant decrease in pain, 
improvement in function and VAS, AOFAS and FADI scores. In addition, treatment 
with BoNT and steroids in the short and medium term is more effective than 
conservative treatment with the use of orthoses, taping , dry needling and night 
splints (6,17). 
In this context, BoNT is presented as a therapeutic option with greater efficacy 
and safety than the use of steroids for PF due to its analgesic and anti-inflammatory 
effect . Therefore, the need to investigate the effectiveness of BoNT is justified . 
Intralesional in patients with PF in the rehabilitation outpatient clinic of the Regional 
General Hospital No. 1 of the IMSS-Yucatán, to evaluate its potential as a non- 
surgical therapeutic alternative and reduce the economic burden associated with 
conservative and invasive treatments. 
 
IV.- Problem Statement and Research Question 
 
 
PF is the most common cause of heel pain, affecting approximately 1 million 
outpatient visits annually worldwide, affecting 1 in 10 people at some point in their 
lives. This ankle and foot disease can cause pain and functional limitation in patients, 
however, most patients resolve the condition conservatively, with various non- 
surgical and surgical therapeutic alternatives available. 
Among these alternatives is the use of intralesional BoNT type a or the use of 
corticosteroids. intralesional , medications available in the hospital's Rehabilitation 
Medicine service. However, there is little information at the international level about 
its effects and it is necessary to know its clinical effects in patients with PF who 
attend the rehabilitation outpatient clinic at the IMSS General Regional Hospital No. 
1 in Yucatán, in order to determine its relevance as a therapeutic option and improve 
the quality of life of patients. 

14 
 
Therefore, the following research question is raised: What are the clinical 
effects of intralesional application of incobotulinum toxin vs corticosteroid in patients 
with plantar fasciitis? 
 
V General Objective 
 
To evaluate the clinical effects of intralesional application of incobotulinum toxin vs 
corticosteroid in patients with plantar fasciitis. 
 
 
V.1 First Specific Objective 
incobotulinum toxin and corticosteroid in the treatment of plantar fasciitis. 
 
V.2 Second Specific Objective 
 
 
To compare the intensity of pain, dorsiflexion range of motion, foot and ankle 
functionality, functional disability index in activities of daily living, and physical activity 
in FP, at the beginning of diagnostic detection, at 4 weeks post infiltration, at two 
months, and at four months after therapeutic intervention. 
 
VI General hypothesis 
Intralesional application of incobotulinum toxin presents a statistically 
significant improvement in pain, dorsiflexion range of motion, foot and ankle 
functionality in patients with plantar fasciitis than intralesional application of 
corticosteroids. 
 
VII Material and Methods 
 
VII.I Design 
 
 
A sequential, simple randomized clinical trial will be conducted. 

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VII.II Universe of study 
Patients entitled to the Regional General Hospital No. 1 “Lic. Ignacio García 
Téllez” IMSS Yucatán Delegation, currently active with a diagnosis of plantar 
fasciitis, referred to the Physical Medicine and Rehabilitation service in a period of 4 
months. 
 
SAMPLE. 
Non-probabilistic sampling of consecutive cases of all patients with plantar 
fasciitis seen in the Physical Medicine and Rehabilitation outpatient clinic of HGR 
No. 1 of IMSS Yucatán in the four-month period and who meet the selection criteria. 
 
SAMPLE SIZE. 
It will be a census type and the sample will be determined by the total number 
of cases, that is, 100% of the patients diagnosed with plantar fasciitis treated in the 
physical medicine and rehabilitation service of the Regional General Hospital No. 1 
of the Mexican Social Security Institute in the four-month period who meet the 
selection criteria. 
 
DEFINITION OF OBSERVATION UNITS. 
 
Experimental group. Group A for patients who accept intralesional infiltration of 
incobotulinum toxin and Group B for patients who accept intralesional infiltration with 
dexamethasone. 
 
Conceptual definition : Group A therapeutic program in which Incobotulinum toxin 
will be administered to patients with plantar fasciitis. 
 
Operational definition: Program in which the program will be administered 2 
ampoules (200 IU) of Incobotulinum toxin , injectable solution presentation 100 IU 
ampoule with powder diluted in 1 ml of 0.9% saline solution in a single application at 
4 points, in addition to a therapeutic exercise program in the teaching service to later 
do it at home that will be done daily for 4 months (cryotherapy for 15 minutes on the 

16 
 
plantar fascia, active mobilizations of the ankle and foot for 5 minutes, stretching 
exercises for the triceps surae and plantar fascia for 20 seconds, 3 repetitions, 
strengthening of intrinsic muscles of the foot). 
 
Conceptual definition : Group B therapeutic program in which dexamethasone will 
be administered to patients with plantar fasciitis. 
 
Operational definition: Program in which 2 ml of dexamethasone will be 
administered in an 8 mg/2 ml ampoule diluted in 2 ml of lidocaine injectable solution 
in a 50 ml bottle (20 mg/ml) in a single application at 1 point, in addition to a 
therapeutic exercise program in the teaching service to later do it at home that will 
be done daily for 4 months (cryotherapy for 15 minutes on the plantar fascia, active 
mobilizations of the ankle and foot for 5 minutes, stretching exercises for the triceps 
surae and plantar fascia for 20 seconds, 3 repetitions, strengthening of intrinsic 
muscles of the foot). 
 
VII.III Period 
The total period will consist of 8 months, of which 4 months will be for 
recruitment and 4 months for follow-up to evaluate its effectiveness in pain 
management, alignment, dorsiflexion range of motion, and foot and ankle 
functionality in plantar fasciitis. 
 
VII.IV .I Selection criteria 
INCLUSION CRITERIA: 
1. Age over 18 years. 
2. Any sex. 
3. Diagnosis of plantar fasciitis (pain in the medial plantar calcaneal tubercle 
which gives rise to the site of plantar fascial insertion into the heel bone and/or 
pain along the path of its three bands) made by a physician specializing in 
Physical Medicine and Rehabilitation. 

17 
 
4. Voluntary acceptance of participation in the study. 
5. Patients entitled to the Mexican Social Security Institute. 
 
EXCLUSION CRITERIA: 
 
1. Diagnosis of ankylosing spondylitis. 
2. Pregnant women. 
3. Previous infiltration treatment with any medication or substance applied to the 
plantar fascia or gastrocnemius muscles in the last six months. 
4. Anticoagulant treatment. 
5. History of local infection in the plantar fascia in the last three months. 
6. Allergic to lidocaine, incobotulinum toxin or dexamethasone. 
7. Patients not entitled to the Mexican Social Security Institute. 
8. Patient's refusal to participate in the study. 
 
ELIMINATION CRITERIA: 
 
1.- Patients who abandon treatment. 
 
VII.5 Methods 
 
VII.VI Methodology 
 
Participants in the study will be patients with a clinical diagnosis of plantar 
fasciitis who will be assessed using the EVA, AOFAS, FADI scales and 
measurement of the ankle dorsiflexion arch. The invitation to participate in the study 
will be extended, patients will be informed about the work to be performed and its 
purpose, and the application of Botulinum Toxin type A or Dexamethasone will 
subsequently be offered. By simple randomization, two study groups will be formed: 
GROUP A: Patients who accept intralesional infiltration with incobotulinum toxin 2 
ampoules (200 IU) injectable solution presentation 100 IU ampoule with powder 
diluted in 1 ml of 0.9% saline solution in a single application in 4 points: insertion of 
the plantar fascia in the calcaneus (50 IU), site of greatest pain in the medial region 
of the plantar arch (50 IU), medial gastrocnemius (50 IU) and lateral gastrocnemius 

18 
 
(50 IU), at the end of the intervention a therapeutic exercise program will be provided 
in the service that will be carried out for 4 weeks. GROUP B: Patients who accept 
intralesional infiltration with 2 ml dexamethasone in an 8 mg/2 ml ampoule diluted in 
2 ml of lidocaine injectable solution in a 50 ml bottle (20 mg/ml) in a single application 
in the anteromedial area of the calcaneus (area of greatest pain), at the end of the 
intervention a therapeutic exercise program will be provided in the service that will 
be carried out for 4 weeks. 
In both cases, at the beginning of the intervention, an informed consent will 
be signed. At the end of the intervention, it will be recommended to avoid pressure 
or rubbing on the application sites, as well as not to take long walks for 48 hours , 
and in case of pain, apply a cold compress on the infiltration site for 10 minutes at 
home 3 times a day for 24 hours and subsequently, after 48 hours, a therapeutic 
exercise program will be provided in the teaching service to later do it at home, which 
will be done daily for 4 months (cryotherapy for 15 minutes on the plantar fascia, 
active mobilizations of the ankle and foot for 5 minutes, stretching exercises for the 
triceps surae and plantar fascia for 20 seconds, 3 repetitions, strengthening of 
intrinsic muscles of the foot). 
Likewise, patients will be assessed in 4 visits: the first at the start of 
diagnostic detection, the second at 4 weeks post infiltration, the third at two months, 
the fourth at four months, with the EVA, AOFAS, FADI scales being assessed in all 
visits, which together will assess pain and functionality and disability of the foot and 
the measurement of dorsiflexion in 2 visits at the start of diagnostic detection and at 
4 months. 
 
VII.V .II Description of variables and units of measurement 
DEPENDENT VARIABLES: 
• Functional clinical status of ankle and foot (AOFAS scale) 
• Functional disability index of the foot and ankle in activities of daily living 
(FADI SCALE) 
• Functional Disability Index of the Foot and Ankle in Sport (FADI SCALE) 
• Functionality (AOFAS Scale) 

19 
 
• Foot Alignment (AOFAS Scale) 
• Pain (EVA, FADI and AOFAS). 
• Ankle and foot disability 
• Ankle dorsiflexion arch 
INDEPENDENT VARIABLES: 
• Age 
• Gender 
• Occupation 
• Physical or sports activity 
• BMI 
• Foot to be treated 
 
 
 
 
 
 
 
Variable 
Definitions 
Variable 
type 
Measure 
ment 
level 
Unit of 
measurement 
Dependent 
CLINICA 
L 
FUNCTIO 
NAL 
STATUS 
OF THE 
ANKLE 
AND 
FOOT 
Conceptual: Term used 
to describe a patient's 
health status or 
condition. 
Operational: Result of 
the total summative 
score of the AOFAS 
scale 
Qualitative 
Nominal 
Excellent=90-100 
Good =80-89 
Medium=70-79 
Poor=<70 
INDEX 
OF 
FUNCTIO 
NAL 
DISABILI 
TY OF 
THE 
FOOT 
AND 
ANKLE 
IN 
ACTIVITI 
ES OF 
DAILY 
LIVING 
Conceptual: Index used 
to assess the result of 
the interaction between 
physical impairments 
and environmental 
barriers that limit full 
participation. 
Operational: Result of 
the total summative 
score of the FADI scale 
Qualitative 
Nominal 
Absence of 
disability or pain = 
100 
Mild=80-99 
Moderate=50-79 
Severe:1-49 
Maximum disability 
level = 0 

20 
 
INDEX 
OF 
FUNCTIO 
NAL 
DISABILI 
TY OF 
THE 
FOOT 
AND 
ANKLE 
IN 
SPORTS 
ACTIVITI 
ES 
Conceptual: Index used 
to assess the result of 
the interaction between 
physical impairments 
and environmental 
barriers that limit full 
participation. 
Operational: Result of 
the total summative 
score of the FADI scale 
Qualitative 
Nominal 
Absence of 
disability or pain = 
100 
Mild=80-99 
Moderate=50-79 
Severe:1-49 
Maximum disability 
level = 0 
PAIN 
Conceptual: unpleasant 
sensory and emotional 
experience associated 
with or similar to that 
associated with actual or 
potential tissue injury ” 
Operational: It will be 
evaluated using the 
FADI scale in the pain 
section, the AOFAS 
scale in the pain section 
and the Visual Analogue 
Pain Scale (VAS) 
Qualitative 
Ordinal 
FADI 
40=None 
30= occasional 
20=moderate 
0=severe 
Qualitative 
Ordinal 
AOFAS 
0=Unbearable 
1=Severe pain 
2=moderate pain 
3= Mild pain 
4=No pain 
Qualitative 
Ordinal 
EVE 
0=absence of pain 
1-4= Mild pain 
5-7= Moderate pain 
8-9= Severe non- 
disabling pain 
10= Worst pain of 
your life, disabling 
pain 
FUNCTIO 
NALITY 
Conceptual: Ability of 
the subject to carry out 
daily life activities. 
Operational: It will be 
assessed with the 
AOFAS scale in the 
section on activity 
function, type of 
footwear, walking 
(maximum distance), 
types of terrain for 
walking, limping. 
Qualitative 
Ordinal 
Activities 
10= No limitation 
and no external 
support 
7= No limitation in 
daily life, but yes in 
sports and without 
external support 
4=Limitation in 
recreational life 
(crutch required) 
0=Severe limitation 
even with crutch 
Qualitative 
Ordinal 
Type of footwear 
5= Any footwear 
3= Comfortable 
shoes only 
0=Special footwear 
or orthoses 
Qualitative 
Ordinal 
Walking (maximum 
distance) 

21 
 
10= More than 2km 
7= Between 1.5 
and 2 km 
4= Between 0.5 
and 1 km 
0=less than 350 
meters 
Qualitative 
Ordinal 
Type of terrain to 
walk on 
10= No difficulty on 
any terrain 
5= Some difficulty 
on uneven terrain 
and stairs 
0=Difficulty on 
uneven terrain and 
stairs 
Qualitative 
Ordinal 
Limp 
10=None 
5=Obvious 
0=Checked 
FUNCTIO 
NALITY 
OF 
ACTIVITI 
ES FOR 
DAILY 
LIVING 
Conceptual: Set of 
features that make 
functions practical and 
useful for daily life 
Operational: It will be 
taken from the FADI 
scale in the functionality 
section in daily living 
activities 
Qualitative 
Ordinal 
Stand up 
0= Unable to 
perform 
1= Extreme 
difficulty 
2=Moderate 
difficulty 
3=Mild difficulty 
4=No difficulty 
5=N/A 
Qualitative 
Ordinal 
Walking on even 
terrain 
0= Unable to 
perform 
1= Extreme 
difficulty 
2=Moderate 
difficulty 
3=Mild difficulty 
4=No difficulty 
5=N/A 
Qualitative 
Ordinal 
Walking on even 
terrain without 
shoes 
0= Unable to 
perform 
1= Extreme 
difficulty 
2=Moderate 
difficulty 
3=Mild difficulty 
4=No difficulty 
5=N/A 

22 
 
Qualitative 
Ordinal 
Walking on uneven 
terrain 
0= Unable to 
perform 
1= Extreme 
difficulty 
2=Moderate 
difficulty 
3=Mild difficulty 
4=No difficulty 
5=N/A 
Qualitative 
Ordinal 
Going up or down 
ramps 
0= Unable to 
perform 
1= Extreme 
difficulty 
2=Moderate 
difficulty 
3=Mild difficulty 
4=No difficulty 
5=N/A 
Qualitative 
Ordinal 
Sleep 
FADI 
0= Unable to 
perform 
1= Extreme 
difficulty 
2=Moderate 
difficulty 
3=Mild difficulty 
4=No difficulty 
5=N/A 
Qualitative 
Ordinal 
Taking the first 
steps after being at 
rest 
0= Unable to 
perform 
1= Extreme 
difficulty 
2=Moderate 
difficulty 
3=Mild difficulty 
4=No difficulty 
5=N/A 
Qualitative 
Ordinal 
Walk for 15 min 
0= Unable to 
perform 
1= Extreme 
difficulty 
2=Moderate 
difficulty 
3=Mild difficulty 
4=No difficulty 
5=N/A 
Walk for 10 min 

23 
 
Qualitative 
Ordinal 
0= Unable to 
perform 
1= Extreme 
difficulty 
2=Moderate 
difficulty 
3=Mild difficulty 
4=No difficulty 
5=N/A 
Qualitative 
Ordinal 
Walk for 5 minutes 
0= Unable to 
perform 
1= Extreme 
difficulty 
2=Moderate 
difficulty 
3=Mild difficulty 
4=No difficulty 
5=N/A 
Qualitative 
Ordinal 
Take care of 
household activities 
0= Unable to 
perform 
1= Extreme 
difficulty 
2=Moderate 
difficulty 
3=Mild difficulty 
4=No difficulty 
5=N/A 
Qualitative 
Ordinal 
Personal care 
activities 
0= Unable to 
perform 
1= Extreme 
difficulty 
2=Moderate 
difficulty 
3=Mild difficulty 
4=No difficulty 
5=N/A 
Qualitative 
Ordinal 
Heavy work 
(pushing/pulling/cli 
mbing or carrying) 
0= Unable to 
perform 
1= Extreme 
difficulty 
2=Moderate 
difficulty 
3=Mild difficulty 
4=No difficulty 
5=N/A 
Qualitative 
Ordinal 
Uphill walk 
0= Unable to 
perform 

24 
 
1= Extreme 
difficulty 
2=Moderate 
difficulty 
3=Mild difficulty 
4=No difficulty 
5=N/A 
Qualitative 
Ordinal 
Downhill walk 
0= Unable to 
perform 
1= Extreme 
difficulty 
2=Moderate 
difficulty 
3=Mild difficulty 
4=No difficulty 
5=N/A 
Qualitative 
Ordinal 
Climb stairs 
0= Unable to 
perform 
1= Extreme 
difficulty 
2=Moderate 
difficulty 
3=Mild difficulty 
4=No difficulty 
5=N/A 
Qualitative 
Ordinal 
Go down stairs 
0= Unable to 
perform 
1= Extreme 
difficulty 
2=Moderate 
difficulty 
3=Mild difficulty 
4=No difficulty 
5=N/A 
Qualitative 
Ordinal 
Perform activities 
of daily living 
0= Unable to 
perform 
1= Extreme 
difficulty 
2=Moderate 
difficulty 
3=Mild difficulty 
4=No difficulty 
5=N/A 
Qualitative 
Ordinal 
Perform 
light/moderate work 
(standing, walking) 
0= Unable to 
perform 
1= Extreme 
difficulty 

25 
 
2=Moderate 
difficulty 
3=Mild difficulty 
4=No difficulty 
5=N/A 
Qualitative 
Ordinal 
Do recreational 
activities 
0= Unable to 
perform 
1= Extreme 
difficulty 
2=Moderate 
difficulty 
3=Mild difficulty 
4=No difficulty 
5=N/A 
Qualitative 
Ordinal 
Climb on tiptoe 
0= Unable to 
perform 
1= Extreme 
difficulty 
2=Moderate 
difficulty 
3=Mild difficulty 
4=No difficulty 
5=N/A 
Qualitative 
Ordinal 
Light to moderate 
work (standing or 
walking) 
0= Unable to 
perform 
1= Extreme 
difficulty 
2=Moderate 
difficulty 
3=Mild difficulty 
4=No difficulty 
5=N/A 
FOOT 
ALIENAT 
ION 
Conceptual: Foot 
measurement used to 
determine the presence 
or absence of deviation 
towards the inside or 
outside of the foot. 
Operational: It will be 
taken from the AOFAS 
scale in the foot 
alignment section 
Qualitative 
Ordinal 
0= Bad 
8= Regular 
15= Good 
PHYSICA 
L OR 
SPORTS 
ACTIVITY 
Conceptual: Any bodily 
movement that requires 
energy expenditure. 
Planned, structured and 
repetitive activity aimed 
at improving or 
maintaining one or more 
Qualitative 
Ordinal 
FADI 
0= Unable to 
perform 
1= Extreme 
difficulty 
2=Moderate 
difficulty 

26 
 
components of physical 
fitness. 
Operational: The ankle 
disability index (FADI) 
scale will be taken in the 
sports section and the 
clinical record to define 
the type of impact. 
3=Mild difficulty 
4=No difficulty 
5=N/A 
Qualitative 
Nominal 
RECORD 
High Impact 
Low impact 
Does not perform 
MOBILIT 
Y ARC 
Conceptual: Range of 
motion (degree of travel) 
or total angular/axial 
displacement allowed at 
a joint 
dosiflexion degrees at 
the time of data 
collection, will be 
expressed in the results 
by mobility range groups 
according to the 
American Academy of 
Orthopedic Surgeons 
AAOS. 
Quantitativ 
e 
Discreet 
≤10°= Functional 
≥20°=Complete 
Independent 
s 
AGE 
Conceptual: time that a 
person has lived from 
birth to a certain 
moment 
Operational: It will be 
taken from the clinical 
record. 
Quantitativ 
e 
Continue 
1,2,3… 
AGE 
GROUP 
Conceptual: a group of 
people who share an 
age or vital moment and 
who may be of statistical 
or academic interest. 
Operational: It will be 
taken from the clinical 
record. 
Qualitative 
Nominal 
Youth=18 years old 
Adults = 19-64 
years 
Senior adult => 65 
years 
GENDER 
Conceptual: It is the 
organic condition that 
distinguishes between 
masculine and feminine. 
Operational: It will be 
taken from the clinical 
record. 
Qualitative 
Nominal 
Female 
Male 
OCCUPA 
TION 
Conceptual: Activity 
carried out by the 
person from which he 
obtains remuneration 
Operational: It will be 
taken from the clinical 
record. 
Qualitative 
Nominal 
(TC) Loading work 
(TO) Office Work 
(H) Home 
(TP) Standing work 

27 
 
BODY 
MASS 
INDEX 
(BMI) 
Conceptual: index used 
to measure the 
relationship between 
weight and height, which 
allows identifying 
overweight and obesity 
in adults according to 
the Ministry of Health, 
resulting from the 
quotient of the formula 
(kilograms) ÷ (square 
meters). 
Operational: It will be 
taken from the clinical 
record. 
Qualitative 
Nominal 
BMI<18.9= 
underweight 
BMI 18.50 - 24.9 = 
Normal 
BMI 25 - 29.9 = 
Overweight 
BMI 30 to 34.9 = 
Grade I obesity 
BMI 35 to 39.9 = 
Grade II obesity 
BMI>40=Grade III 
obesity 
FOOT TO 
BE 
TREATE 
D 
Conceptual: leg 
extremity, formed by a 
structure of bones, 
joints, muscles and 
other components. 
Operational: It will be 
taken from the clinical 
record. 
Qualitative 
Nominal 
Right 
Left 
 
PROCEDURE AND STATISTICAL ANALYSIS. 
 
 
The information will be processed using Microsoft Excel version 2010 and 
SPSS version 11.5. A descriptive analysis will be performed using mean, median, 
average, standard deviation, percentages and proportions; and a comparative 
analysis using the Wilcoxon test . 
In order to identify possible confounding variables , clinical and demographic 
characteristics will be compared. Student 's t test will be used to compare 
quantitative variables and CHi2 will be used to compare qualitative variables. If there 
is a difference in any of the variables, a multivariate model will be entered to adjust 
the effectiveness of the intervention. A value of p < 0.05 will be considered 
statistically significant. All analyses will be performed by intention to treat using the 
statistical program SPSS version 21. 
 
PRESENTATION OF INFORMATION. 

28 
 
The information will be processed through the tools available in Microsoft 
Office® 2019 (Word, Excel, Power Point) as well as in the statistical/computer 
program IBM SPSS Software® version 21. 
The information found and the findings will be presented through statements, tables 
and graphs as appropriate. 
 
VII.V.III Human Resources 
Primary care physicians and third-year resident physicians in the specialty of 
rehabilitation medicine qualified to perform intralesional procedures . 
 
VII.V.IV Material resources 
 
 
PROVIDED BY THE INSTITUTE: 
- 
2 Vials per patient of Incobotulinum Toxin , (Institutional KEY: 
0100043620101)): (200 IU) presentation 100 IU ampoule in powder 
- 
1 vial of Dexamethasone (institutional KEY: 01000042410000): 2 ml ampoule 
presentation of 8 mg/2 ml 
- 
2ml of Lidocaine (Institutional CODE: 01000002620000): injectable solution, 
bottle with 50 ml (20mg/ml) to dilute dexamethasone. 
- 
1 ml of 0.9% saline solution (institutional CODE: 01000036080000): 0.9% 
injectable solution for every 100 ml, container with 250 ml to dilute with 
Botulinum toxin. 
- 
27g sterile needles 
- 
Cotton swabs 
- 
70% ethyl alcohol 
- 
1 ml syringes 
- 
5 ml syringes 
- 
White sheets 
- 
Goniometer 

29 
 
VIII Ethical Considerations 
The design of this study complies with the institutional, national and 
international standards that govern health research, as well as those that correspond 
to research on human beings. Including the Standard that establishes the provisions 
for Health research at the Mexican Social Security Institute 2000-001-009 31; the 
General Health Law and the Declaration of Helsinki (Fortaleza, Brazil, 2014). As well 
as the Declaration of Helsinki. 
According to the regulations of the General Health Law, Title Two “Ethical 
Aspects of Research in Human Beings”, Chapter I, this research protocol is 
considered to be research with greater than minimum risk, since random methods 
of assignment to therapeutic schemes will be used, for which a letter of informed 
consent will be requested. (Annex I) 
The principles of bioethics are respected. It will be considered fair, since the 
results obtained in the present study will allow us to guide the management of 
patients with PF and guide it in order to obtain better functionality. There is justice, 
since there will be an adequate balance between the investment made and the 
knowledge obtained. The integrity of the subject is not put at risk, so the principle of 
non-maleficence is respected. The aim is to obtain results that improve the care of 
this type of patients (beneficence). 
The study is considered to be of minimal risk for participants, since the only 
procedure will be intralesional infiltration of Incobotulinum Toxin or Dexamethasone, 
with a physical therapy program and four assessment instruments, according to 
article 17, section II. The persons included will receive a clear and concrete 
explanation of the objective of the study in order to respect their dignity and well- 
being during the study; they will be informed of the freedom to withdraw from the 
study at any time when they no longer wish to participate without this affecting their 
personal interests. 
Necessary measures will be taken to protect patient data through encryption, 
so as not to identify the name or personal data of patients that may compromise their 
integrity. 

30 
 
The research project will be submitted to the local committee on Research 
and Ethics of Health Research No. 3401. Where it will be evaluated and verified that 
the necessary criteria are met to be able to carry it out, and if necessary, authorize 
it . 
 
IX Feasibility 
This study has a high probability of completion due to the prevalence of plantar 
fasciitis in the Rehabilitation service of HGR 1. 
 
Gant Schedule ). 
CLINICAL EFFECTS OF INTRALESIONAL APPLICATION OF 
INCOBOTULINUM TOXIN VS CORTICOSTEROID IN PATIENTS WITH 
PLANTAR FASCIITIS . 
Months 2024-2025 
November- 
December 
January- 
February 
March-April 
May-June 
July-August 
 
September 
October 
November 
 
December 
Gathering information. 
Preparation of the research protocol. 
Submission of the protocol for evaluation by the 
ethics and research committee. 
Data processing and analysis. 
Data interpretation 
Report preparation 
Communication of results 

31 
 
XI References : 
( 1) Brotzman SB, Manske RC. Rehabilitation Orthopedic Clinic + Expertconsult . 
Elsevier Health Sciences; 2012. 
(2) Hamstra-Wright KL, Huxel Bliven KC, Bay RC, Aydemir B. Risk factors for plantar 
fasciitis in physically active individuals: A systematic review and meta-analysis. 
Sports Health [Internet]. 2021;13(3):296–303. 
(3) Ruiz-Hernández IM, Gascó -Adrien J, Buen-Ruiz C, Perelló-Moreno L, Tornero- 
Prieto C, Barrantes-Delgado G, et al. Botulinum toxin A versus platelet rich plasma 
ultrasound-guided injection in the treatment of plantar fasciitis: A randomised 
controlled trial. Foot Ankle Surg [Internet]. 2024;30(2):117–22 
(4) Ahadi T, Nik SS, Forogh B, Madani SP, Raissi GR. Comparison of the effect of 
ultrasound-guided injection of botulinum toxin type A and corticosteroid in the 
treatment of chronic plantar fasciitis: A randomized controlled trial. Am J Phys Med 
Rehabil [Internet]. 2022;101(8):733–7. 
(5) Rhim HC, Kwon J, Park J, Borg-Stein J, Tenforde AS. A systematic review of 
systematic reviews on the epidemiology, evaluation, and treatment of plantar 
fasciitis. Life (Basel) [Internet]. 2021;11(12):1287. 
(6) Buchanan BK, Sina RE, Kushner D. Plantar Fasciitis. [Updated 2024 Jan 7]. In: 
StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan. 
(7) Trojian , T., & Tucker, A.K. (2019). Plantar Fasciitis. American family physician, 
99(12), 744–750. 
(8) Acosta-Olivo C, Simental- Mendía LE, Vilchez-Cavazos F, Peña-Martínez VM, 
Elizondo- Rodíguez J, Simental- Mendía M. Clinical efficacy of botulinum toxin in the 
treatment of plantar fasciitis: A systematic review and meta -analysis of randomized 
Controlled Trials. Arch Phys Med Rehabil [Internet]. 2022;103(2):364-371. 
(9) Díaz López AM, Guzmán Carrasco P. Effectiveness of different physical 
therapies in conservative treatment of plantar fasciitis: systematic review. Rev Esp 
Public Health [Internet]. 2014;88(1):157–78. 
(10) Whittaker GA, Munteanu SE, Menz HB, Tan JM, Rabusin CL, Landorf KB. Foot 
orthoses for plantar heel pain: a systematic review and meta-analysis. Br J Sports 
Med [Internet]. 2018;52(5):322–8. 
(11) Van de Water ATM, Speksnijder CM. Efficacy of taping for the treatment of 
plantar fasciosis : a systematic review of controlled trials. J Am Podiatr Med Assoc 
[Internet]. 2010;100(1):41–51. 
(12) He C, Ma H. Effectiveness of trigger point dry needling for plantar heel pain: a 
meta-analysis of seven randomized controlled trials. J Pain Res [Internet]. 
2017;10:1933 –42. 
(13) Schneider HP, Baca JM, Carpenter BB, Dayton PD, Fleischer AE, Sachs BD. 
American college of foot and ankle surgeons clinical consensus statement: 
Diagnosis and treatment of adult acquired infracalcaneal heel pain. J Foot Ankle 
Surg [Internet]. 2018;57(2):370–81. 

32 
 
(1 4) Probe RA, Baca M, Adams R, Preece C. Night splint treatment for plantar 
fasciitis. A prospective randomized study. Clin Orthop Relat Res [Internet]. 
1999;368(368):190–5. 
(15) Lee WCC, Wong WY, Kung E, Leung AKL. Effectiveness of adjustable 
dorsiflexion night splint in combination with accommodative foot orthosis on plantar 
fasciitis. J Rehabil Res Dev [Internet]. 2012;49(10):1557–64. 
(16) Elizondo-Rodriguez J, Araujo-Lopez Y, Moreno-Gonzalez JA, Cardenas- 
Estrada E, Mendoza-Lemus O, Acosta-Olivo C. A comparison of botulinum toxin a 
and intralesional steroids for the treatment of plantar fasciitis: a randomized, double- 
blinded study: A randomized, double-blinded study. Foot Ankle Int [Internet]. 
2013;34(1):8–14. 
(17) Li Z, Xia C, Yu A, Qi B. Ultrasound- versus palpation-guided injection of 
corticosteroid for plantar fasciitis: A meta-analysis. PLoS One [Internet]. 2014;9(3 ):e 
92671. 
(18) Chou ACC, Ng SYC, Koo KOT. Endoscopic plantar fasciotomy improves early 
postoperative results: A retrospective comparison of outcomes after endoscopic 
versus open plantar fasciotomy. J Foot Ankle Surg [Internet]. 2016;55(1):9–15. 
(19) Choudhury S, Baker MR, Chatterjee S, Kumar H. Botulinum toxin: An update 
on pharmacology and newer products in development. Toxins ( Basel ) [Internet]. 
2021;13(1):58. 
(20) Camargo CP, Xia J, Costa CS, Gemperli R, Tatini MDC, Bulsara MK, et al. 
Botulinum toxin type A for facial wrinkles. Cochrane Book [Internet]. 2021;2022. 
(21) Dressler D, Johnson EA. Botulinum toxin therapy: past, present and future 
developments. J Neural Transm (Vienna) [Internet]. 2022;129(5–6):829–33. 
(22) Dressler D. Clinical pharmacology of botulinum toxin drugs. handb Exp 
Pharmacol [Internet]. 2021;263:93 –106. 

33 
 
ANNEXES 
Appendix 1 EVA PAIN RATING SCALE 
 
 
 
Visual Analogue Scale 
 
Instructions: 
Please circle the number that best fits your level of pain, with 0 being no pain and 10 
being the most pain. 
 
 
 

34 
 
Appendix 2 AMERICAN FOOT AND ANKLE SOCIETY SCALE (AOFAS) 
Instructions: Please answer each question by circling the number that most 
accurately describes your current condition. 
 
 
 

35 
 
Appendix 3 THE FOOT AND ANKLE DISABILITY INDEX (FADI) SCALE 
 
Instructions: Please answer each question according to the answer that best describes 
your condition within the past 7 days by marking the appropriate number in the box. If the 
activity in question is limited by something other than your ankle or foot, mark N/A (Not 
Applicable). 
 
Score Activities of Daily Living FADI  
=sum of number of answers answered n ( max = 
26)/ n*4 X100 
 
FADI Sport Score __ = sum of number of answered questions n ( max = 8)/ n*4 X100 
 

36 
 
 

37 
 
Appendix 4 MEASUREMENT OF THE ANKLE DORSIFLEXION MOBILITY 
RANGE 
Patient Name: 
ACTIVE MOBILITY RANGE OF ANKLE DORSIFLEXION 
VISIT 1 
(start of diagnostic detection) 
VISIT 2 
(4 months post infiltration) 
 
 
 
 

38 
 
Annex 5 DATA COLLECTION INSTRUMENT 
 
 
MEXICAN INSTITUTE OF SOCIAL SECURITY 
YUCATAN DELEGATION 
HEALTH EDUCATION AND RESEARCH COORDINATION 
REGIONAL GENERAL HOSPITAL NO. 1 “LIC. IGNACIO GARCÍA TELLEZ” 
 
 
DATA COLLECTION INSTRUMENT 
 
TITLE: CLINICAL EFFECTS OF INTRALESIONAL APPLICATION OF INCOBOTULINUM TOXIN VS 
CORTICOSTEROID IN PATIENTS WITH PLANTAR FASCIITIS . 
 
Sociodemographic 
Name: 
Social Security 
Number: 
Age: 
Sex: 
Occupation: 
Foot to be treated : 
Sports activity: 
Phones: 
 
 
Physical examination. 
Applications and evaluations 
DATE 
EVE 
AOOFAS 
FADI 
DORSIFLEXION 
Start of 
diagnosis 
4 weeks 
N/A 
2 months 
N/A 
4 months 
Appendix 6 THERAPEUTIC EXERCISE PROGRAM 
Weight: 
Size: 
BMI: 

39 
 
7 INFORM 
Therapeutic exercise program in the teaching service to later do it at home, which will be carried out 
daily for 4 months: 
1. Cryotherapy for 15 minutes on the plantar fascia and active ankle and foot mobilization for 5 
minutes ( Fig 1) 
2. Stretching exercises for the triceps surae (affected leg behind the other with the toes pointing 
towards the front heel, bend the front knee while the back knee is left stretched and with the 
heels fixed on the floor for 20 seconds) and plantar fascia for 20 seconds, 3 reps ( Fig 2) 
3. Strengthening intrinsic muscles of the foot ( Fig 3) 
 
FOLLOW-UP PERIOD 
PERFORM FROM MONDAY TO SUNDAY 
DAILY 
Start of diagnosis 
4 weeks 
2 months 
4 months 
 
 
 
 
Annex 
FIG 3 
ED CONSENT 
FIG 1 
FIG 2 

40 
 
MEXICAN INSTITUTE OF SOCIAL SECURITY 
EDUCATION, RESEARCH AND HEALTH POLICIES UNIT. 
HEALTH RESEARCH COORDINATION. 
INFORMED CONSENT LETTER. 
(ADULTS) 
INFORMED CONSENT LETTER TO PARTICIPATE IN RESEARCH PROTOCOLS. 
Study name: 
intralesional application of Incobotulinum Toxin vs. 
Corticosteroid in patients with plantar fasciitis. 
Place and date: 
HGR No.1, IMSS, Merida, Yucatan.2024. 
Justification and objective of the study: 
intralesional botulinum toxin A with the effect of 
intralesional corticosteroids in patients diagnosed 
with plantar fasciitis. 
Procedures: 
The group of patients referred to the physical 
medicine and rehabilitation service will be selected 
and will meet the selection criteria. They will 
receive their first consultation and will be invited to 
take part in the study. They will allow the use of 
data from their clinical records that are considered 
necessary for this study. They will answer 
questionnaires and participate in measurements 
upon admission and 4 weeks after entering the 
program. 
Possible risks or discomforts 
Pain at the application site, muscle pain typical of 
any rehabilitation program. 
Possible benefits you will receive by 
participating in this study: 
The application program of Incobotulinum Toxin or 
Dexamethasone offers the patient the possibility of 
reducing pain and stiffness as well as improving the 
functionality of the affected ankle and foot. 
Information on results and treatment 
alternatives: 
Incobotulinum 
Toxin 
or 
intralesional 
Dexamethasone will be announced . 
Participation or withdrawal: 
I have been informed that I am free to decide 
whether or not to participate in this study and that I 
may withdraw from it at any time without this 
affecting the care I receive from the Institute. 
Privacy and confidentiality: 
I was told that my personal data will be encrypted 
and protected in such a way that it can only be 
identified by the Researchers of this study or, 
where appropriate, future studies. 

41 
 
In case of doubts or clarifications related to the study, you can contact: 
Principal Investigator: 
- - - 
Contributors: 
- - - 
In case of doubts or clarifications regarding your rights as a participant, you may contact: Research 
Ethics Commission of the CNIC of the IMSS: Avenida Cuauhtémoc 330 4th floor Block “B” of the 
Congress Unit, Colonia Doctores. Mexico City, CP 06720. Telephone (55) 56 27 69 00 extension 
21230, Email: comision.etica@imss.gob.mx 
 
Name and signature of the subject. 
 
Name and signature of the person obtaining 
consent. 
 
Name and signature of Witness 1 
 
Name and signature of Witness 2