Achilles Tendon RuptureNCT04727047
NMES for Achilles Tendon Rupture
A study testing neuromuscular electrical stimulation in people with Achilles Tendon Rupture, run by Penn State University at 1 site in United States.
Trial summary
The majority of patients suffering an Achilles tendon rupture develop long term functional deficits in the affected leg. The goal of the proposed study is to evaluate a new rehabilitation protocol using Neuromuscular Electrical Stimulation (NMES) for reducing muscle atrophy and improving tendon properties. Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Achilles Tendon Rupture
- What is being tested?
- neuromuscular electrical stimulation
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 8 participants
- Where
- 1 siteUnited States
- Study dates
- 15 Feb 2023to 31 Dec 2024
- Phase
- Interventional
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Achilles tendon rupture
Who cannot join
- Those unable to understand spoken English.
- Participants treated non-operatively
- Augmented surgical repair (i.e., use of additional tissue at the repair site)
- Tendon ruptures associated with the use of fluoroquinolones (Examples include ciprofloxacin (Cipro), gemifloxacin (Factive), levofloxacin (Levaquin), moxifloxacin (Avelox), norfloxacin (Noroxin), and ofloxacin (Floxin))
- Allergy to ultrasound gel
- Any other condition affecting the ability of the participant to walk or jump
- Any other health conditions known to impair normal healing: Diabetes, Cardiovascular conditions decreasing blood supply to the leg
- Those unable to consent
Trial locations and contacts
1 site in 1 country.
United States1 site
Penn State University
State College, Pennsylvania, 16802
About this study
Official title: Neuromuscular Electrical Stimulation for Achilles Tendon Rupture Rehabilitation
The majority of patients suffering an Achilles tendon rupture develop long term functional deficits in the affected leg. The goal of the proposed study is to evaluate a new rehabilitation protocol using Neuromuscular Electrical Stimulation (NMES) for reducing muscle atrophy and improving tendon properties. If proven beneficial, the proposed protocol can be easily adopted and incorporated as part of routine care for Achilles tendon rupture.
Read the detailed description
Achilles Tendon Ruptures (ATR) are common and permanently affect the function of the lower leg. Regardless of treatment approach the majority of patients develop long term functional deficits, which include decreased plantar flexion strength, lower heel-rise height, and altered gait patterns. It is believed that tendon lengthening and calf muscle atrophy, which develop during the first few weeks of recovery, are major factors contributing to these functional deficits. The initial development of atrophy is likely caused by reduced loading and muscle activity of the affected leg. However, long-term atrophy may be related to tendon elongation. On the other hand, tendon elongation initially rises during the first few weeks of unloading and slowly reduces, but not completely, when loading is resumed. However, atrophied calf muscles may not provide sufficient loading for optimal tendon recovery. Therefore, there seems to be vicious spiral between tendon elongation and muscle atrophy.
The objective of this study is to develop a neuromuscular electrical stimulation (NMES) rehabilitation protocol for Achilles tendon ruptures. Our preliminary data has shown that force applied to the tendon can be modulated using electrical intensity and pad placement. Therefore, NMES can produce significant contraction in the calf muscles and induce controllable, low-magnitude, cyclic loading to the tendon; which cannot be achieved with voluntary muscle contractions. This approach can potentially overcome limitations of the current rehabilitation protocols.
- Conditions
- Achilles Tendon Rupture
- Being tested
- neuromuscular electrical stimulation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
neuromuscular electrical stimulationDevice
All subjects will receive standard rehabilitation for Achilles tendon repair. In addition, neuromuscular electrical stimulation will be applied to the calf muscles of the injured leg. The stimulation volume, the electrode placement and the intensity of the stimulation will be selected based on the mechanical strength of healing Achilles tendon. The intervention will be applied for 6 weeks after repair.
| Study group | Role | What they receive |
|---|---|---|
| Neuromuscular Electrical Stimulation | Active comparator | Neuromuscular electrical stimulation will be applied to the calf muscles. The level of stimulation will be increased weekly from 10 to 30 mA during the first 6 weeks after surgery.
In addition, patients will follow standard therapy for Achilles tendon repair. Receives: Device: neuromuscular electrical stimulation |
| Control | No intervention | Patients will follow standard therapy for Achilles tendon repair. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Ability to Perform a Single Heel Rise
The ability of patients to perform a single heel rise using the injured will be tested.
Measured: Week 12
Secondary outcomes (7)
Tendon Length
Length from the tendon insertion to the myotendinous junction
Measured: Week12
Tendon Thickness
Tendon thickness measured via ultrasound imaging at the rupture location
Measured: Week 6, 12
Gastrocnemius Muscle Cross-sectional Area
Area of the tendon measured via ultrasound imaging at the rupture location
Measured: Week 6, 12
Soleus Muscle Estimated Volume
Muscle volume estimated from ultrasound imaging
Measured: Week 6, 12
Foot and Ankle Outcome Score (FAOS)
Score that assesses patient pain, other symptoms, function in daily living, function in sport and recreation, and foot/ankle related quality of life. Scores range from 0 to 100 with a score of 0 indicating the worst possible foot/ankle symptoms and 100 indicating no foot/ankle symptoms.
Measured: Week 6, 12
Achilles Total Rupture Score
It consists of ten items evaluating aspects of symptoms and function. Each item has scores ranging between 0 and 10 on a Likert scale. The instrument therefore has a maximum score of 100, which corresponds to no symptoms and full function.
Measured: Week 6, 12
Tampa Scale for Kinesiophobia (TSK)
Questionnaire based on evaluation of fear of movement, fear of physical activity, and fear avoidance. The total score of the scale range from 17- 68, where 17 means no kinesiophobia, 68 means severe kinesiophobia, and score ± 37 indicates there is kinesiophobia.
Measured: Week 6, 12
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted27 Jan 2021
- Study start15 Feb 2023
- Primary completion31 Dec 2024
- Study completion31 Dec 2024
Why it stopped: Recruitment of the number of required patients not completed
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Achilles Tendon RuptureStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 8 participants (actual)
Sponsor and investigators
- Lead sponsor
- Penn State University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Daniel Cortes, Penn State University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04727047
- Sponsor's protocol ID
- STUDY00016121
- Status last verified
- Aug 2026
- First submitted
- 15 Oct 2020
- Last updated
- 22 Sep 2026
- Results posted
- Yes, on ClinicalTrials.gov
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 22 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Neuromuscular Electrical Stimulation for Achilles Tendon Rupture Rehabilitation
- ClinicalTrials.gov ID
- NCT04727047
- Acronym / sponsor ID
- STUDY00016121
- Conditions
- Achilles Tendon Rupture
- Study type
- Interventional
- Recruitment status
- TerminatedReason stopped: Recruitment of the number of required patients not completed
- Enrolment
- 8 participants (actual)
- Lead sponsor
- Penn State UniversityUniversity, hospital or other
- Study start
- 15 Feb 2023 (actual)
- Primary completion
- 31 Dec 2024 (actual)
- Study completion
- 31 Dec 2024 (actual)
- First posted
- 27 Jan 2021 (actual)
- Results
- Posted 22 Sep 2026
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The majority of patients suffering an Achilles tendon rupture develop long term functional deficits in the affected leg. The goal of the proposed study is to evaluate a new rehabilitation protocol using Neuromuscular Electrical Stimulation (NMES) for reducing muscle atrophy and improving tendon properties. If proven beneficial, the proposed protocol can be easily adopted and incorporated as part of routine care for Achilles tendon rupture.
Detailed description
Achilles Tendon Ruptures (ATR) are common and permanently affect the function of the lower leg. Regardless of treatment approach the majority of patients develop long term functional deficits, which include decreased plantar flexion strength, lower heel-rise height, and altered gait patterns. It is believed that tendon lengthening and calf muscle atrophy, which develop during the first few weeks of recovery, are major factors contributing to these functional deficits. The initial development of atrophy is likely caused by reduced loading and muscle activity of the affected leg. However, long-term atrophy may be related to tendon elongation. On the other hand, tendon elongation initially rises during the first few weeks of unloading and slowly reduces, but not completely, when loading is resumed. However, atrophied calf muscles may not provide sufficient loading for optimal tendon recovery. Therefore, there seems to be vicious spiral between tendon elongation and muscle atrophy.
The objective of this study is to develop a neuromuscular electrical stimulation (NMES) rehabilitation protocol for Achilles tendon ruptures. Our preliminary data has shown that force applied to the tendon can be modulated using electrical intensity and pad placement. Therefore, NMES can produce significant contraction in the calf muscles and induce controllable, low-magnitude, cyclic loading to the tendon; which cannot be achieved with voluntary muscle contractions. This approach can potentially overcome limitations of the current rehabilitation protocols.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Neuromuscular Electrical Stimulation | Active comparator | Device: neuromuscular electrical stimulationNeuromuscular electrical stimulation will be applied to the calf muscles. The level of stimulation will be increased weekly from 10 to 30 mA during the first 6 weeks after surgery. In addition, patients will follow standard therapy for Achilles tendon repair. |
| Control | No intervention | –Patients will follow standard therapy for Achilles tendon repair. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (1 listed)
- Achilles tendon rupture
Key exclusion criteria (8 listed)
- Those unable to understand spoken English.
- Participants treated non-operatively
- Augmented surgical repair (i.e., use of additional tissue at the repair site)
- Tendon ruptures associated with the use of fluoroquinolones (Examples include ciprofloxacin (Cipro), gemifloxacin (Factive), levofloxacin (Levaquin), moxifloxacin (Avelox), norfloxacin (Noroxin), and ofloxacin (Floxin))
- Allergy to ultrasound gel
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| neuromuscular electrical stimulationAll subjects will receive standard rehabilitation for Achilles tendon repair. In addition, neuromuscular electrical stimulation will be applied to the calf muscles of the injured leg. The stimulation volume, the electrode placement and the intensity of the stimulation will be selected based on the mechanical strength of healing Achilles tendon. The intervention will be applied for 6 weeks after repair. | Device | Neuromuscular Electrical Stimulation |
Primary outcome
Ability to Perform a Single Heel Rise
Time frame: Week 12
The ability of patients to perform a single heel rise using the injured will be tested.
7 secondary outcomes
Tendon Length
Time frame: Week12
Tendon Thickness
Time frame: Week 6, 12
Gastrocnemius Muscle Cross-sectional Area
Time frame: Week 6, 12
Soleus Muscle Estimated Volume
Time frame: Week 6, 12
Foot and Ankle Outcome Score (FAOS)
Time frame: Week 6, 12
Achilles Total Rupture Score
Time frame: Week 6, 12
Tampa Scale for Kinesiophobia (TSK)
Time frame: Week 6, 12
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 22 Sep 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Individual participant dataSharing planned: Undecided
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing neuromuscular electrical stimulation in people with Achilles Tendon Rupture, run by Penn State University at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: stopped early, as of the sponsor's last update on 22 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Yes. Results are posted in the registry (first posted 22 Sep 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Ability to Perform a Single Heel Rise (time frame: Week 12). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 22 Sep 2026.