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Knee OsteoarthritisKOA-tDCSNCT07291791

tDCS for Pain Modulation in Knee Osteoarthritis

A study testing Transcranial Direct Current Stimulation (tDCS) in people with Knee Osteoarthritis, run by Suez Canal University at 1 site in Egypt.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

Knee osteoarthritis (KOA) is a common condition that causes long-lasting knee pain and difficulty with daily activities. Many patients have pain that is stronger than expected from joint changes because the nervous system becomes more sensitive to pain. Read more about this study

Who is it for?
Ages 35 years and older
Conditions the study is for
Knee Osteoarthritis
What is being tested?
Transcranial Direct Current Stimulation (tDCS)
Type of treatment
Medical device
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
102 participants
Where
1 siteEgypt
Study dates
20 Dec 2025to 31 May 2026
Phase
Interventional
Are there results?
None posted in the registry

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 35 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Diagnosis of knee osteoarthritis (KOA) according to the American College of Rheumatology (ACR) clinical criteria.
  • Adults of both sexes aged 35 years or older.
  • Clinical knee pain persisting for at least 3 months.
  • Average knee pain intensity ≥ 4/10 on the Numerical Rating Scale (NRS; 0-10) during the previous 24 hours, with one dominant affected knee.
  • Central sensitization phenotype: impaired conditioned pain modulation (CPM), defined as no change or a reduction in pressure pain threshold (PPT) after the conditioning stimulus, corresponding to a PPT ratio ≥ 1 (pre-to-post stimulus).
  • Prior pharmacological pain management with NSAIDs and/or SNRIs discontinued due to adverse effects, intolerance, or contraindications, and able to complete the required washout period (2 weeks for NSAIDs and 4 weeks for SNRIs) before baseline assessment.
  • Able and willing to provide written informed consent and comply with study procedures.

Who cannot join

  • Participants will be excluded if they have any condition that could affect cortical excitability, confound outcome measures, or interfere with tDCS safety, including:
  • Other chronic pain conditions associated with central sensitization (e.g., fibromyalgia).
  • Inflammatory arthropathies (e.g., rheumatoid arthritis, psoriatic arthritis, systemic lupus erythematosus).
  • Neuropathic pain syndromes (e.g., lumbar or cervical radiculopathy).
  • Any clinically significant or unstable systemic disease (cardiovascular, hepatic, renal, or metabolic disorders).
  • Pregnancy or active malignancy.
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  • Neurological or psychiatric disorders including epilepsy, history of syncope, traumatic brain injury with residual deficit, or major depressive disorder.
  • Current participation in physiotherapy, electrotherapy, or exercise rehabilitation programs.
  • Metallic implants or implanted electrical devices (e.g., pacemakers, cochlear implants, deep brain stimulators).
  • Cognitive impairment interfering with understanding instructions or providing informed consent.
  • Dermatological contraindications at stimulation or testing sites (e.g., open wounds, infection, irritation).
  • History of alcohol or substance abuse, or current use of centrally acting medications that alter cortical excitability (e.g., benzodiazepines).

Trial locations and contacts

1 site in 1 country.

Egypt1 site
  • Suez Canal University Hospitals - Physical Medicine, Rheumatology and Rehabilitation Outpatient Clinics

    Ismailia, 41522

Other trials in Egypt

About this study

Official title: Evaluation of the Neuromodulatory Effects of Transcranial Direct Current Stimulation on Pain in Knee Osteoarthritis Patients: A Double Blind Randomized Controlled Trial

Knee osteoarthritis (KOA) is a common condition that causes long-lasting knee pain and difficulty with daily activities. Many patients have pain that is stronger than expected from joint changes because the nervous system becomes more sensitive to pain. Transcranial direct current stimulation (tDCS) is a non-invasive technique that uses a small electrical current applied to the scalp to help reduce pain sensitivity.

This study will test whether active tDCS over the primary motor cortex can reduce pain and improve function in people with knee osteoarthritis. A total of 102 participants will be randomly assigned to receive either active tDCS or sham (placebo) stimulation. All participants will receive 15 sessions over three weeks. We will measure pain intensity, pain sensitivity, physical function, depression, cognition, and quality of life before the treatment, after the 3-week treatment program, and again at the 1-month follow-up.

Read the detailed description

Knee osteoarthritis (KOA) is a major cause of chronic pain, disability, and reduced quality of life. In many patients, the severity of pain exceeds structural joint damage due to peripheral and central sensitization, including impaired conditioned pain modulation (CPM). Such dysfunction in descending inhibitory pathways contributes to pain amplification and poor response to standard treatments. Transcranial direct current stimulation (tDCS) is a non-invasive neuromodulatory technique capable of modulating cortical excitability, enhancing descending inhibition, and potentially restoring altered pain processing mechanisms.

This randomized, assessor- and participant-blinded, sham-controlled clinical trial will investigate the neuromodulatory effects of anodal primary motor cortex (M1) tDCS in patients with KOA exhibiting impaired CPM. A total of 102 participants who meet eligibility criteria will be randomly assigned (1:1) to receive either active anodal M1-tDCS (2 mA, 20 minutes per session) or sham stimulation, using identical electrode placement and brief initial stimulation to maintain blinding. Both groups will receive 15 sessions administered over three consecutive weeks.

Assessments will be conducted at baseline, immediately after the intervention, and at 1-month follow-up. Primary outcomes include changes in pain intensity measured by the Visual Analogue Scale (VAS) and Brief Pain Inventory (BPI). Secondary outcomes include peripheral and central sensitization measures-Pressure Pain Threshold (PPT), Conditioned Pain Modulation (CPM), Central Sensitization Inventory (CSI), and PainDETECT-as well as functional outcomes assessed using the WOMAC index, Timed Up and Go (TUG) test, and One-Leg Stance. Additional outcomes include depressive symptoms (Beck Depression Inventory, BDI), cognitive function (Mini-Mental State Examination, MMSE), and health-related quality of life (SF-12).

This study aims to provide a comprehensive evaluation of the analgesic and neuromodulatory effects of tDCS in KOA, and to clarify its impact on pain modulation, pain sensitization, physical function, depression, cognition, and overall quality of life.

Being tested
Transcranial Direct Current Stimulation (tDCS)
Keywords
Knee Pain, Osteoarthritis, tDCS, Neuromodulation, Central Sensitization
Medical subject headings
Osteoarthritis, Knee, Osteoarthritis

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Transcranial Direct Current Stimulation (tDCS)Device

    Also called tDCS

    Transcranial Direct Current Stimulation (tDCS) is a non-invasive neuromodulation technique that applies low-intensity direct current to modulate cortical excitability. In this trial, stimulation is delivered over the primary motor cortex (M1) using saline-soaked sponge electrodes. For the active arm, anodal tDCS is applied at 2 mA for 20 minutes per session, for 15 sessions over three weeks. For the sham arm, the same electrode placement and device settings are used, but the current is ramped down after approximately 30 seconds to mimic the sensation of active stimulation without producing neuromodulatory effects.

Study groups in NCT07291791
Study groupRoleWhat they receive
Active tDCSExperimentalParticipants in this arm (active tDCS group) will receive active anodal transcranial direct current stimulation (tDCS) applied over the primary motor cortex (M1). Stimulation will be delivered at 2 mA for 20 minutes per session, for a total of 15 sessions (five sessions per week for three consecutive weeks). Electrode placement follows standardized M1 montage protocols.
Receives: Device: Transcranial Direct Current Stimulation (tDCS)
Sham tDCSSham comparatorParticipants in this arm (sham tDCS group) will receive sham tDCS using identical electrode placement and device settings as the active tDCS arm. The current will be applied for approximately 30 seconds and then gradually ramped down to zero to mimic the initial tingling sensation of active stimulation while delivering no effective stimulation. A total of 15 sessions will be administered over three weeks.
Receives: Device: Transcranial Direct Current Stimulation (tDCS)

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Change in Pain Intensity (VAS and BPI Scores)

    Pain intensity will be assessed using the Visual Analogue Scale (VAS) and the Brief Pain Inventory (BPI). The primary outcome is the change in VAS and BPI pain scores from baseline to immediately post-intervention and one-month follow-up.

    Measured: Baseline, immediately after the 15-session intervention, and at 1-month follow-up.

Secondary outcomes (9)
  1. Change in Pressure Pain Threshold (PPT)

    PPT will be assessed using a digital pressure algometer at two standardized locations on the affected side-the medial knee joint line and the ipsilateral lower leg-to evaluate peripheral sensitization, as well as at a remote site on the forearm to assess central sensitization. The primary outcome will be the change in mean PPT values across three time points: baseline, immediately post-intervention, and 1-month follow-up.

    Measured: Baseline, immediately after completing the 15 treatment sessions, and at 1-month follow-up

  2. Change in Central Sensitization using Central Sensitization Inventory (CSI) Score

    Central sensitization symptoms will be assessed using the Central Sensitization Inventory (CSI). The outcome is the change in CSI total score (0-100) between baseline, post-intervention, and follow-up.

    Measured: Baseline, immediately after the 15-session intervention, and at 1-month follow-up

  3. Change in Conditioned Pain Modulation (CPM) Efficiency

    CPM efficiency will be evaluated using the submaximal-effort tourniquet test. Pressure pain threshold (PPT) will be measured immediately before and after the conditioning stimulus. CPM efficiency will be calculated as the ratio of pre-conditioning PPT to post-conditioning PPT. A pre-to-post stimulus PPT ratio greater than or equal to 1 (indicating no change or a reduction in PPT after conditioning) will be classified as impaired CPM, reflecting deficient descending inhibitory pain modulation. The outcome is the change in CPM efficiency across baseline, post-intervention, and 1-month follow-up.

    Measured: Baseline, immediately after the 15-session intervention, and at 1-month follow-up

  4. Change in neuropathic-like pain features (PainDETECT Score)

    Neuropathic-like pain features will be assessed using the PainDETECT questionnaire. The outcome is the change in PainDETECT total score across baseline, post-intervention, and follow-up.

    Measured: Baseline, immediately after the 15-session intervention, and at 1-month follow-up

  5. Change in physical function (WOMAC Score)

    Pain, stiffness, and physical function will be evaluated using the WOMAC questionnaire. Higher WOMAC scores indicate greater physical dysfunction. The outcome is the change in WOMAC total and subscale scores from baseline to post-intervention and follow-up.

    Measured: Baseline, immediately after the 15-session intervention, and at 1-month follow-up

  6. Change in functional performance using Timed Up and Go (TUG) Performance and One-Leg Stance (OLS) Time.

    Functional performance will be assessed using the Timed Up and Go (TUG) test for functional mobility and the One-Leg Stance (OLS) test for balance. The outcome is defined as the change in TUG completion time and the change in maximum OLS stance duration (in seconds) across baseline, post-intervention, and 1-month follow-up.

    Measured: Baseline, immediately after the 15-session intervention, and at 1-month follow-up

  7. Change in depressive symptoms using the Beck Depression Inventory (BDI) Score

    Depressive symptoms will be assessed using the Beck Depression Inventory (BDI). The outcome is the change in total BDI score between baseline, post-intervention, and follow-up.

    Measured: Baseline, immediately after the 15-session intervention, and at 1-month follow-up

  8. Change in cognitive function using Mini-Mental State Examination (MMSE) Score

    Cognitive function will be evaluated using the Mini-Mental State Examination (MMSE). The outcome is the change in MMSE score across baseline, post-intervention, and 1-month follow-up.

    Measured: Baseline, immediately after the 15-session intervention, and at 1-month follow-up

  9. Change in SF-12 Quality of Life Score

    Health-related quality of life will be assessed using the SF-12 questionnaire. The outcome is the change in physical and mental component summary scores from baseline to post-intervention and 1-month follow-up.

    Measured: Baseline, immediately after the 15-session intervention, and at 1-month follow-up

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted18 Dec 2025
  2. Study start20 Dec 2025
  3. Primary completion20 May 2026
  4. Study completion31 May 2026

Resources

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
Model description
Two parallel arms: active tDCS and sham tDCS.
Masking
Double blind
Who is masked
Participant, Outcomes assessor
Enrolment
102 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07291791
Sponsor's protocol ID
tDCS121225
Acronym
KOA-tDCS
Status last verified
Dec 2025
First submitted
5 Dec 2025
Last updated
2 Jun 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No: Individual participant data (IPD) will not be shared because this is a single-center academic doctoral research project, and the ethical approval obtained does not permit public sharing of patient-level data. All collected data are confidential and will be used solely for the purposes of this study in accordance with institutional and national data protection regulations.

Questions about this trial

What is this clinical trial studying?

A study testing Transcranial Direct Current Stimulation (tDCS) in people with Knee Osteoarthritis, run by Suez Canal University at 1 site in Egypt.

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 7 inclusion and 12 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: finished, as of the sponsor's last update on 2 Jun 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 Egypt. 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. Some participants in this study may receive a placebo. 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?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

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?

Change in Pain Intensity (VAS and BPI Scores) (time frame: Baseline, immediately after the 15-session intervention, and at 1-month follow-up.). 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 2 Jun 2026.

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