Efficacy of Percutaneous Electrolysis in the Treatment of Achilles Tendinopathy

Achilles Tendinopathy Clinical Trial

Official title:

Evaluation of the Efficacy of Adding Low-intensity Percutaneous Musculoskeletal Electrolysis to the Conservative Treatment of Noninsertional Achilles Tendinopathy: a Randomized Controlled Clinical Trial

Clinical Trial Details — Status: Recruiting

Administrative data

• NCT number: NCT05301959
• Other study ID #: 5694
• Status: Recruiting
• Phase: N/A
• Start date: July 1, 2023
• Est. completion date: December 2025

Study information

• Verified date: July 2023
• Source: Maimonides University
• Contact: Santiago M d'Almeida, PT SCS
• Phone: 01140573099
• Email: dalmeida.santiago[@]maimonides.edu
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

Achilles tendinopathy (AT) is one of the most reported myotendinous pathologies due to overuse in the literature. In the general adult population, its incidence is 2.35 cases per 1,000 patients, with no difference between men and women. The international literature reports that up to 29% of patients fail with conservative treatment.

Within physiotherapy, new alternatives for the treatment of tendinopathies arise, applying electric currents percutaneously, which from a mechanical effect associated to the use of a needle and an electric effect by the use of galvanic currents, generate a local inflammatory response; activation of the central nervous system and analgesia.

The aim of the research is to evaluate the efficacy of adding low intensity percutaneous electrolysis to the treatment with a high load eccentric exercise program based on the protocol of Silbernagel et al. in adults with Achilles tendinopathy to improve its functionality.

A randomized, double-blind, blinded, evaluator-blinded, controlled clinical trial will be conducted in parallel groups (experimental treatment vs. sham treatment), with a follow-up at 26 and 52 weeks after the first intervention. Non-probability and intentional sampling will be performed.

Recruitment information / eligibility

• Status: Recruiting
• Enrollment: 102
• Est. completion date: December 2025
• Est. primary completion date: December 2024
• Accepts healthy volunteers: No
• Gender: All
• Age group: 18 Years to 65 Years

Eligibility

Inclusion Criteria:

• Presence of symptoms in one or both Achilles tendons with a minimum duration of two months. In case the symptoms are bilateral, the intervention or placebo will only be administered and its results evaluated- in the limb with greater symptomatology. If it is not possible to differentiate which one presents greater pain, the right Achilles tendon will be chosen.

• Spontaneous pain of at least three points measured by a visual analog scale (VAS), reproducible by palpation between 2 and 6 cm above the insertion of the Achilles tendon in the calcaneal bone.

• Evidence of tendinopathy by MRI.

• Presence of post-static dyskinesia.

• Willingness to not perform additional treatments (such as footwear modifications, physical therapy, orthotics, injections, or surgery) for Achilles tendon pain during the conduct of the trial.

• Willingness to attempt to discontinue self-administration of medications (NSAIDs) for pain relief Achilles tendon(s) pain for at least 14 days prior to baseline assessment and during the course of the trial.

Exclusion Criteria:

• Presence or suspicion of pregnancy.

• Previous surgical intervention on the AT in the symptomatic leg(s)

• Total or partial rupture in the symptomatic AT

• Chronic ankle instability, in the foot with symptomatic tendon(s).

• Pathologies that can derive in pain in the region of the AT without being proper of the picture. (e.g.: osteoarthritis, impingement syndromes).

• Presence of arthritis or any metabolic or endocrine disorder (type 1 or 2 diabetes).

• Psychological disorders.

• Oncologic history.

• Treatment with quinolones or fluoroquinolones during the last two years.

• Treatment with statins for the control of hypercholesterolemia for more than two months

• Treatments within or at the periphery of the Achilles tendon, with anesthetics, corticosteroids or any other pharmacological agent during the last three months.

• Needle phobia

• Allergy to metal

Related Conditions & MeSH terms

• Achilles Tendinopathy
• Tendinopathy

Intervention

Device:
• low intensity percutaneous musculoskeletal electrolysis
An acupuncture needle (0.30mm X 25mm) will be introduced into the device's strut. With the equipment on and with a base intensity of 120µA, the acupuncture needle is introduced in a proximal-distal and postero-anterior direction, in the area of the Achilles tendon body. The position of the needle will be checked with ultrasound and once the point to be treated is reached, the working intensity will be increased up to 600 µA. The emission will be maintained until the participant reports a pain of 60/100 in VAS. At that moment, the emission will be paused completely until the participant reports a sensation of at least 20/100 in VAS. After this period the emission will be continued at 600 µA. This cycle will continue until the emission lasts for more than 120 sec, continuously. At this point, the needle will be repositioned to repeat the emission protocol a maximum of 3 times in total.
• Sham application
A modification will be made in a second equipment, closing the circuit with a 10kO resistor inside the equipment, in the output strand chip. Allowing the simulation of emission without emitting current to the participant and without being able to appreciate any type of alteration in the handling of the equipment, by the operators. Therefore, the same steps will be followed as in the experimental group.

Other:
• Silbernagel protocol
The Silbernagel et al. protocol comprises several heel raising exercises with concentric and eccentric movements, performed on two legs and one leg. It is composed of 3 sets of 15 repetitions and that during the exercises allows pain to be present, but not being disabling. The exercises will be performed only once a day. The progression will be made by changing from standing exercises to monopodal support, moving from concentric-eccentric to purely eccentric loading, adding weight in a backpack (in steps of 5 kg when pain does not exceed 5 in the pain monitoring model) and finally using fast rebound exercises and plyometric exercises.

Locations

Country	Name	City	State
Argentina	Maimonides University	Ciudad Autonoma de Buenos Aires	Caba

Sponsors (1)

Lead Sponsor	Collaborator
Maimonides University

Country where clinical trial is conducted

Argentina, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Victorian Institute of Sport Assessment - Achilles - Baseline	patient reported outcomes specifically designed for the assessment of pain and function in the achilles tendinopathy. It has a scale from 0 (worst) to 100 (best).	Baseline
Primary	Victorian Institute of Sport Assessment - Achilles - Week 1	patient reported outcomes specifically designed for the assessment of pain and function in the achilles tendinopathy. It has a scale from 0 (worst) to 100 (best).	one week at study entry
Primary	Victorian Institute of Sport Assessment - Achilles - Week 2	patient reported outcomes specifically designed for the assessment of pain and function in the achilles tendinopathy. It has a scale from 0 (worst) to 100 (best).	two week at study entry
Primary	Victorian Institute of Sport Assessment - Achilles - Week 3	patient reported outcomes specifically designed for the assessment of pain and function in the achilles tendinopathy. It has a scale from 0 (worst) to 100 (best).	three week at study entry
Primary	Victorian Institute of Sport Assessment - Achilles - Week 4	patient reported outcomes specifically designed for the assessment of pain and function in the achilles tendinopathy. It has a scale from 0 (worst) to 100 (best).	four week at study entry
Primary	Victorian Institute of Sport Assessment - Achilles - Week 5	patient reported outcomes specifically designed for the assessment of pain and function in the achilles tendinopathy. It has a scale from 0 (worst) to 100 (best).	five week at study entry
Primary	Victorian Institute of Sport Assessment - Achilles - Week 6	patient reported outcomes specifically designed for the assessment of pain and function in the achilles tendinopathy. It has a scale from 0 (worst) to 100 (best).	six week at study entry
Primary	Victorian Institute of Sport Assessment - Achilles - Week 7	patient reported outcomes specifically designed for the assessment of pain and function in the achilles tendinopathy. It has a scale from 0 (worst) to 100 (best).	seven week at study entry
Primary	Victorian Institute of Sport Assessment - Achilles - Week 8	patient reported outcomes specifically designed for the assessment of pain and function in the achilles tendinopathy. It has a scale from 0 (worst) to 100 (best).	eight week at study entry
Primary	Victorian Institute of Sport Assessment - Achilles - Week 9	patient reported outcomes specifically designed for the assessment of pain and function in the achilles tendinopathy. It has a scale from 0 (worst) to 100 (best).	nine week at study entry
Primary	Victorian Institute of Sport Assessment - Achilles - Week 10	patient reported outcomes specifically designed for the assessment of pain and function in the achilles tendinopathy. It has a scale from 0 (worst) to 100 (best).	ten week at study entry
Primary	Victorian Institute of Sport Assessment - Achilles - Week 11	patient reported outcomes specifically designed for the assessment of pain and function in the achilles tendinopathy. It has a scale from 0 (worst) to 100 (best).	eleven week at study entry
Primary	Victorian Institute of Sport Assessment - Achilles - Week 12	patient reported outcomes specifically designed for the assessment of pain and function in the achilles tendinopathy. It has a scale from 0 (worst) to 100 (best).	twelve week at study entry
Primary	Victorian Institute of Sport Assessment - Achilles - Week 26	patient reported outcomes specifically designed for the assessment of pain and function in the achilles tendinopathy. It has a scale from 0 (worst) to 100 (best).	twenty-six week at study entry
Primary	Victorian Institute of Sport Assessment - Achilles - Week 52	patient reported outcomes specifically designed for the assessment of pain and function in the achilles tendinopathy. It has a scale from 0 (worst) to 100 (best).	fifty-two week at study entry
Secondary	visual analog scale - Baseline	The intensity of pain experienced during a sequence of three monopodal countermovement jumps with both hands on the waist will be evaluated on a graduated scale. A maximum of three jumps will be performed and the highest jump will be recorded. Immediately afterwards, participants will be asked to indicate with an "X" on a 100mm line the intensity of pain experienced in the Achilles tendon. It has a scale from 0 (no pain) to 100 (worst pain).	Baseline
Secondary	visual analog scale - Week 1	The intensity of pain experienced during a sequence of three monopodal countermovement jumps with both hands on the waist will be evaluated on a graduated scale. A maximum of three jumps will be performed and the highest jump will be recorded. Immediately afterwards, participants will be asked to indicate with an "X" on a 100mm line the intensity of pain experienced in the Achilles tendon. It has a scale from 0 (no pain) to 100 (worst pain).	one week at study entry
Secondary	visual analog scale - Week 2	The intensity of pain experienced during a sequence of three monopodal countermovement jumps with both hands on the waist will be evaluated on a graduated scale. A maximum of three jumps will be performed and the highest jump will be recorded. Immediately afterwards, participants will be asked to indicate with an "X" on a 100mm line the intensity of pain experienced in the Achilles tendon. It has a scale from 0 (no pain) to 100 (worst pain).	Two week at study entry
Secondary	visual analog scale - Week 3	The intensity of pain experienced during a sequence of three monopodal countermovement jumps with both hands on the waist will be evaluated on a graduated scale. A maximum of three jumps will be performed and the highest jump will be recorded. Immediately afterwards, participants will be asked to indicate with an "X" on a 100mm line the intensity of pain experienced in the Achilles tendon. It has a scale from 0 (no pain) to 100 (worst pain).	three week at study entry
Secondary	visual analog scale - Week 4	The intensity of pain experienced during a sequence of three monopodal countermovement jumps with both hands on the waist will be evaluated on a graduated scale. A maximum of three jumps will be performed and the highest jump will be recorded. Immediately afterwards, participants will be asked to indicate with an "X" on a 100mm line the intensity of pain experienced in the Achilles tendon. It has a scale from 0 (no pain) to 100 (worst pain).	four week at study entry
Secondary	visual analog scale - Week 5	The intensity of pain experienced during a sequence of three monopodal countermovement jumps with both hands on the waist will be evaluated on a graduated scale. A maximum of three jumps will be performed and the highest jump will be recorded. Immediately afterwards, participants will be asked to indicate with an "X" on a 100mm line the intensity of pain experienced in the Achilles tendon. It has a scale from 0 (no pain) to 100 (worst pain).	five week at study entry
Secondary	visual analog scale - Week 6	The intensity of pain experienced during a sequence of three monopodal countermovement jumps with both hands on the waist will be evaluated on a graduated scale. A maximum of three jumps will be performed and the highest jump will be recorded. Immediately afterwards, participants will be asked to indicate with an "X" on a 100mm line the intensity of pain experienced in the Achilles tendon. It has a scale from 0 (no pain) to 100 (worst pain).	six week at study entry
Secondary	visual analog scale - Week 7	The intensity of pain experienced during a sequence of three monopodal countermovement jumps with both hands on the waist will be evaluated on a graduated scale. A maximum of three jumps will be performed and the highest jump will be recorded. Immediately afterwards, participants will be asked to indicate with an "X" on a 100mm line the intensity of pain experienced in the Achilles tendon. It has a scale from 0 (no pain) to 100 (worst pain).	seven week at study entry
Secondary	visual analog scale - Week 8	The intensity of pain experienced during a sequence of three monopodal countermovement jumps with both hands on the waist will be evaluated on a graduated scale. A maximum of three jumps will be performed and the highest jump will be recorded. Immediately afterwards, participants will be asked to indicate with an "X" on a 100mm line the intensity of pain experienced in the Achilles tendon. It has a scale from 0 (no pain) to 100 (worst pain).	eight week at study entry
Secondary	visual analog scale - Week 9	The intensity of pain experienced during a sequence of three monopodal countermovement jumps with both hands on the waist will be evaluated on a graduated scale. A maximum of three jumps will be performed and the highest jump will be recorded. Immediately afterwards, participants will be asked to indicate with an "X" on a 100mm line the intensity of pain experienced in the Achilles tendon. It has a scale from 0 (no pain) to 100 (worst pain).	nine week at study entry
Secondary	visual analog scale - Week 10	The intensity of pain experienced during a sequence of three monopodal countermovement jumps with both hands on the waist will be evaluated on a graduated scale. A maximum of three jumps will be performed and the highest jump will be recorded. Immediately afterwards, participants will be asked to indicate with an "X" on a 100mm line the intensity of pain experienced in the Achilles tendon. It has a scale from 0 (no pain) to 100 (worst pain).	ten week at study entry
Secondary	visual analog scale - Week 11	The intensity of pain experienced during a sequence of three monopodal countermovement jumps with both hands on the waist will be evaluated on a graduated scale. A maximum of three jumps will be performed and the highest jump will be recorded. Immediately afterwards, participants will be asked to indicate with an "X" on a 100mm line the intensity of pain experienced in the Achilles tendon. It has a scale from 0 (no pain) to 100 (worst pain).	eleven week at study entry
Secondary	visual analog scale - Week 12	The intensity of pain experienced during a sequence of three monopodal countermovement jumps with both hands on the waist will be evaluated on a graduated scale. A maximum of three jumps will be performed and the highest jump will be recorded. Immediately afterwards, participants will be asked to indicate with an "X" on a 100mm line the intensity of pain experienced in the Achilles tendon. It has a scale from 0 (no pain) to 100 (worst pain).	twelve week at study entry
Secondary	visual analog scale - Week 26	The intensity of pain experienced during a sequence of three monopodal countermovement jumps with both hands on the waist will be evaluated on a graduated scale. A maximum of three jumps will be performed and the highest jump will be recorded. Immediately afterwards, participants will be asked to indicate with an "X" on a 100mm line the intensity of pain experienced in the Achilles tendon. It has a scale from 0 (no pain) to 100 (worst pain).	twenty-six week at study entry
Secondary	visual analog scale - Week 52	The intensity of pain experienced during a sequence of three monopodal countermovement jumps with both hands on the waist will be evaluated on a graduated scale. A maximum of three jumps will be performed and the highest jump will be recorded. Immediately afterwards, participants will be asked to indicate with an "X" on a 100mm line the intensity of pain experienced in the Achilles tendon. It has a scale from 0 (no pain) to 100 (worst pain).	fifty-two week at study entry
Secondary	The Foot and Ankle Ability Measure - Baseline	an evaluative instrument that assesses functional limitations for those with foot- and ankle-related disorders. it's a patient reported outcomes which allows to quantify sport activity and participation. It has a scale from 0 (worst) to 100 (best). It consists of 29 questions, divided into 2 subscales, activities of daily living and sports activities. The criterion for discharge is a value greater than or equal to 90 points.	Baseline
Secondary	The Foot and Ankle Ability Measure - Week 1	an evaluative instrument that assesses functional limitations for those with foot- and ankle-related disorders. it's a patient reported outcomes which allows to quantify sport activity and participation. It has a scale from 0 (worst) to 100 (best). It consists of 29 questions, divided into 2 subscales, activities of daily living and sports activities. The criterion for discharge is a value greater than or equal to 90 points.	one week at study entry
Secondary	The Foot and Ankle Ability Measure - Week 2	an evaluative instrument that assesses functional limitations for those with foot- and ankle-related disorders. it's a patient reported outcomes which allows to quantify sport activity and participation. It has a scale from 0 (worst) to 100 (best). It consists of 29 questions, divided into 2 subscales, activities of daily living and sports activities. The criterion for discharge is a value greater than or equal to 90 points.	two week at study entry
Secondary	The Foot and Ankle Ability Measure - Week 3	an evaluative instrument that assesses functional limitations for those with foot- and ankle-related disorders. it's a patient reported outcomes which allows to quantify sport activity and participation. It has a scale from 0 (worst) to 100 (best). It consists of 29 questions, divided into 2 subscales, activities of daily living and sports activities. The criterion for discharge is a value greater than or equal to 90 points.	three week at study entry
Secondary	The Foot and Ankle Ability Measure - Week 4	an evaluative instrument that assesses functional limitations for those with foot- and ankle-related disorders. it's a patient reported outcomes which allows to quantify sport activity and participation. It has a scale from 0 (worst) to 100 (best). It consists of 29 questions, divided into 2 subscales, activities of daily living and sports activities. The criterion for discharge is a value greater than or equal to 90 points.	four week at study entry
Secondary	The Foot and Ankle Ability Measure - Week 5	an evaluative instrument that assesses functional limitations for those with foot- and ankle-related disorders. it's a patient reported outcomes which allows to quantify sport activity and participation. It has a scale from 0 (worst) to 100 (best). It consists of 29 questions, divided into 2 subscales, activities of daily living and sports activities. The criterion for discharge is a value greater than or equal to 90 points.	five week at study entry
Secondary	The Foot and Ankle Ability Measure - Week 6	an evaluative instrument that assesses functional limitations for those with foot- and ankle-related disorders. it's a patient reported outcomes which allows to quantify sport activity and participation. It has a scale from 0 (worst) to 100 (best). It consists of 29 questions, divided into 2 subscales, activities of daily living and sports activities. The criterion for discharge is a value greater than or equal to 90 points.	six week at study entry
Secondary	The Foot and Ankle Ability Measure - Week 7	an evaluative instrument that assesses functional limitations for those with foot- and ankle-related disorders. it's a patient reported outcomes which allows to quantify sport activity and participation. It has a scale from 0 (worst) to 100 (best). It consists of 29 questions, divided into 2 subscales, activities of daily living and sports activities. The criterion for discharge is a value greater than or equal to 90 points.	seven week at study entry
Secondary	The Foot and Ankle Ability Measure - Week 8	an evaluative instrument that assesses functional limitations for those with foot- and ankle-related disorders. it's a patient reported outcomes which allows to quantify sport activity and participation. It has a scale from 0 (worst) to 100 (best). It consists of 29 questions, divided into 2 subscales, activities of daily living and sports activities. The criterion for discharge is a value greater than or equal to 90 points.	eight week at study entry
Secondary	The Foot and Ankle Ability Measure - Week 9	an evaluative instrument that assesses functional limitations for those with foot- and ankle-related disorders. it's a patient reported outcomes which allows to quantify sport activity and participation. It has a scale from 0 (worst) to 100 (best). It consists of 29 questions, divided into 2 subscales, activities of daily living and sports activities. The criterion for discharge is a value greater than or equal to 90 points.	nine week at study entry
Secondary	The Foot and Ankle Ability Measure - Week 10	an evaluative instrument that assesses functional limitations for those with foot- and ankle-related disorders. it's a patient reported outcomes which allows to quantify sport activity and participation. It has a scale from 0 (worst) to 100 (best). It consists of 29 questions, divided into 2 subscales, activities of daily living and sports activities. The criterion for discharge is a value greater than or equal to 90 points.	ten week at study entry
Secondary	The Foot and Ankle Ability Measure - Week 11	an evaluative instrument that assesses functional limitations for those with foot- and ankle-related disorders. it's a patient reported outcomes which allows to quantify sport activity and participation. It has a scale from 0 (worst) to 100 (best). It consists of 29 questions, divided into 2 subscales, activities of daily living and sports activities. The criterion for discharge is a value greater than or equal to 90 points.	eleven week at study entry
Secondary	The Foot and Ankle Ability Measure - Week 12	an evaluative instrument that assesses functional limitations for those with foot- and ankle-related disorders. it's a patient reported outcomes which allows to quantify sport activity and participation. It has a scale from 0 (worst) to 100 (best). It consists of 29 questions, divided into 2 subscales, activities of daily living and sports activities. The criterion for discharge is a value greater than or equal to 90 points.	twelve week at study entry
Secondary	The Foot and Ankle Ability Measure - Week 26	an evaluative instrument that assesses functional limitations for those with foot- and ankle-related disorders. it's a patient reported outcomes which allows to quantify sport activity and participation. It has a scale from 0 (worst) to 100 (best). It consists of 29 questions, divided into 2 subscales, activities of daily living and sports activities. The criterion for discharge is a value greater than or equal to 90 points.	twenty-six week at study entry
Secondary	The Foot and Ankle Ability Measure - Week 52	an evaluative instrument that assesses functional limitations for those with foot- and ankle-related disorders. it's a patient reported outcomes which allows to quantify sport activity and participation. It has a scale from 0 (worst) to 100 (best). It consists of 29 questions, divided into 2 subscales, activities of daily living and sports activities. The criterion for discharge is a value greater than or equal to 90 points.	fifty-two week at study entry
Secondary	ultrasound Shear Wave elastography - baseline	Shear Wave Elastography (SWS), which consists of a special ultrasound methodology that allows quantitative characterization of the elastic capacity of a tissue through the propagation velocity of the ultrasound wave. The Siemens Acuson S2000 system with a model 9L4 linear transducer will be used.; The patients will be placed on a table in ventral decubitus and the ankle outside the plane of the table in neutral position. To determine the point to be scanned, the maximum perpendicular distance between the anterior and posterior limits of the tendon between 2 to 6 cm from the insertion in the calcaneus will be taken and this value will be reported in mm.; The SWS value will be expressed in m/s. The range of SWS is 0-9 m/s. The standard SWS measurement window size shall be 1cm2 , with a region of interest of 3mm. Three measurements will be recorded in each plane (regions of interest) where homogeneous tissue is considered and the average value of the 6 measurements will be reported.	Baseline
Secondary	ultrasound Shear Wave elastography - Week 4	Shear Wave Elastography (SWS), which consists of a special ultrasound methodology that allows quantitative characterization of the elastic capacity of a tissue through the propagation velocity of the ultrasound wave. The Siemens Acuson S2000 system with a model 9L4 linear transducer will be used.; The patients will be placed on a table in ventral decubitus and the ankle outside the plane of the table in neutral position. To determine the point to be scanned, the maximum perpendicular distance between the anterior and posterior limits of the tendon between 2 to 6 cm from the insertion in the calcaneus will be taken and this value will be reported in mm.; The SWS value will be expressed in m/s. The range of SWS is 0-9 m/s. The standard SWS measurement window size shall be 1cm2 , with a region of interest of 3mm. Three measurements will be recorded in each plane (regions of interest) where homogeneous tissue is considered and the average value of the 6 measurements will be reported.	four week at study entry
Secondary	ultrasound Shear Wave elastography - Week 8	Shear Wave Elastography (SWS), which consists of a special ultrasound methodology that allows quantitative characterization of the elastic capacity of a tissue through the propagation velocity of the ultrasound wave. The Siemens Acuson S2000 system with a model 9L4 linear transducer will be used.; The patients will be placed on a table in ventral decubitus and the ankle outside the plane of the table in neutral position. To determine the point to be scanned, the maximum perpendicular distance between the anterior and posterior limits of the tendon between 2 to 6 cm from the insertion in the calcaneus will be taken and this value will be reported in mm.; The SWS value will be expressed in m/s. The range of SWS is 0-9 m/s. The standard SWS measurement window size shall be 1cm2 , with a region of interest of 3mm. Three measurements will be recorded in each plane (regions of interest) where homogeneous tissue is considered and the average value of the 6 measurements will be reported.	eight week at study entry
Secondary	ultrasound Shear Wave elastography - Week 12	Shear Wave Elastography (SWS), which consists of a special ultrasound methodology that allows quantitative characterization of the elastic capacity of a tissue through the propagation velocity of the ultrasound wave. The Siemens Acuson S2000 system with a model 9L4 linear transducer will be used.; The patients will be placed on a table in ventral decubitus and the ankle outside the plane of the table in neutral position. To determine the point to be scanned, the maximum perpendicular distance between the anterior and posterior limits of the tendon between 2 to 6 cm from the insertion in the calcaneus will be taken and this value will be reported in mm.; The SWS value will be expressed in m/s. The range of SWS is 0-9 m/s. The standard SWS measurement window size shall be 1cm2 , with a region of interest of 3mm. Three measurements will be recorded in each plane (regions of interest) where homogeneous tissue is considered and the average value of the 6 measurements will be reported.	twelve week at study entry
Secondary	ultrasound Shear Wave elastography - Week 26	Shear Wave Elastography (SWS), which consists of a special ultrasound methodology that allows quantitative characterization of the elastic capacity of a tissue through the propagation velocity of the ultrasound wave. The Siemens Acuson S2000 system with a model 9L4 linear transducer will be used.; The patients will be placed on a table in ventral decubitus and the ankle outside the plane of the table in neutral position. To determine the point to be scanned, the maximum perpendicular distance between the anterior and posterior limits of the tendon between 2 to 6 cm from the insertion in the calcaneus will be taken and this value will be reported in mm.; The SWS value will be expressed in m/s. The range of SWS is 0-9 m/s. The standard SWS measurement window size shall be 1cm2 , with a region of interest of 3mm. Three measurements will be recorded in each plane (regions of interest) where homogeneous tissue is considered and the average value of the 6 measurements will be reported.	twenty-six week at study entry
Secondary	ultrasound Shear Wave elastography - Week 52	Shear Wave Elastography (SWS), which consists of a special ultrasound methodology that allows quantitative characterization of the elastic capacity of a tissue through the propagation velocity of the ultrasound wave. The Siemens Acuson S2000 system with a model 9L4 linear transducer will be used.; The patients will be placed on a table in ventral decubitus and the ankle outside the plane of the table in neutral position. To determine the point to be scanned, the maximum perpendicular distance between the anterior and posterior limits of the tendon between 2 to 6 cm from the insertion in the calcaneus will be taken and this value will be reported in mm.; The SWS value will be expressed in m/s. The range of SWS is 0-9 m/s. The standard SWS measurement window size shall be 1cm2 , with a region of interest of 3mm. Three measurements will be recorded in each plane (regions of interest) where homogeneous tissue is considered and the average value of the 6 measurements will be reported.	fifty-two week at study entry
Secondary	Vienna Achilles tendon morphological score - MRI - baseline	A 1.5T Siemens Healthcare 1.5T scanner will be used for the MRI evaluation, using a gradient strength of 40 mT/m and an 8-channel coil. The standard MRI protocol will be identical for all examinations and will consist of a localizer set and three morphological MR sequences: 1) a sagittal fat-suppressed sequence; 2) a sagittal T1 sagittal spin echo (SE) sequence and 3) a T2-w sequence.; Once the images are obtained, they will be evaluated with the "Vienna Achilles tendon morphological score" (VIMATS) protocol proposed by Apprich S. (2021) which conforms a semiquantitative rating scale where the score is composed of four different parameters: (1) thickness, (2) continuity, (3) signal and (4) associated pathologies. It has a continuous numerical scale from 0 to 100 where the higher the score, the better the patient's stage.	Baseline
Secondary	Vienna Achilles tendon morphological score - MRI - Week 4	A 1.5T Siemens Healthcare 1.5T scanner will be used for the MRI evaluation, using a gradient strength of 40 mT/m and an 8-channel coil. The standard MRI protocol will be identical for all examinations and will consist of a localizer set and three morphological MR sequences: 1) a sagittal fat-suppressed sequence; 2) a sagittal T1 sagittal spin echo (SE) sequence and 3) a T2-w sequence.; Once the images are obtained, they will be evaluated with the "Vienna Achilles tendon morphological score" (VIMATS) protocol proposed by Apprich S. (2021) which conforms a semiquantitative rating scale where the score is composed of four different parameters: (1) thickness, (2) continuity, (3) signal and (4) associated pathologies. It has a continuous numerical scale from 0 to 100 where the higher the score, the better the patient's stage.	four week at study entry
Secondary	Vienna Achilles tendon morphological score - MRI - Week 8	A 1.5T Siemens Healthcare 1.5T scanner will be used for the MRI evaluation, using a gradient strength of 40 mT/m and an 8-channel coil. The standard MRI protocol will be identical for all examinations and will consist of a localizer set and three morphological MR sequences: 1) a sagittal fat-suppressed sequence; 2) a sagittal T1 sagittal spin echo (SE) sequence and 3) a T2-w sequence.; Once the images are obtained, they will be evaluated with the "Vienna Achilles tendon morphological score" (VIMATS) protocol proposed by Apprich S. (2021) which conforms a semiquantitative rating scale where the score is composed of four different parameters: (1) thickness, (2) continuity, (3) signal and (4) associated pathologies. It has a continuous numerical scale from 0 to 100 where the higher the score, the better the patient's stage.	eight week at study entry
Secondary	Vienna Achilles tendon morphological score - MRI - Week 12	A 1.5T Siemens Healthcare 1.5T scanner will be used for the MRI evaluation, using a gradient strength of 40 mT/m and an 8-channel coil. The standard MRI protocol will be identical for all examinations and will consist of a localizer set and three morphological MR sequences: 1) a sagittal fat-suppressed sequence; 2) a sagittal T1 sagittal spin echo (SE) sequence and 3) a T2-w sequence.; Once the images are obtained, they will be evaluated with the "Vienna Achilles tendon morphological score" (VIMATS) protocol proposed by Apprich S. (2021) which conforms a semiquantitative rating scale where the score is composed of four different parameters: (1) thickness, (2) continuity, (3) signal and (4) associated pathologies. It has a continuous numerical scale from 0 to 100 where the higher the score, the better the patient's stage.	twelve week at study entry
Secondary	Vienna Achilles tendon morphological score - MRI - Week 26	A 1.5T Siemens Healthcare 1.5T scanner will be used for the MRI evaluation, using a gradient strength of 40 mT/m and an 8-channel coil. The standard MRI protocol will be identical for all examinations and will consist of a localizer set and three morphological MR sequences: 1) a sagittal fat-suppressed sequence; 2) a sagittal T1 sagittal spin echo (SE) sequence and 3) a T2-w sequence.; Once the images are obtained, they will be evaluated with the "Vienna Achilles tendon morphological score" (VIMATS) protocol proposed by Apprich S. (2021) which conforms a semiquantitative rating scale where the score is composed of four different parameters: (1) thickness, (2) continuity, (3) signal and (4) associated pathologies. It has a continuous numerical scale from 0 to 100 where the higher the score, the better the patient's stage.	twenty-six week at study entry
Secondary	Vienna Achilles tendon morphological score - MRI - Week 52	A 1.5T Siemens Healthcare 1.5T scanner will be used for the MRI evaluation, using a gradient strength of 40 mT/m and an 8-channel coil. The standard MRI protocol will be identical for all examinations and will consist of a localizer set and three morphological MR sequences: 1) a sagittal fat-suppressed sequence; 2) a sagittal T1 sagittal spin echo (SE) sequence and 3) a T2-w sequence.; Once the images are obtained, they will be evaluated with the "Vienna Achilles tendon morphological score" (VIMATS) protocol proposed by Apprich S. (2021) which conforms a semiquantitative rating scale where the score is composed of four different parameters: (1) thickness, (2) continuity, (3) signal and (4) associated pathologies. It has a continuous numerical scale from 0 to 100 where the higher the score, the better the patient's stage.	fifty-two week at study entry