NCT07291791

tDCS for Pain Modulation in Knee Osteoarthritis

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

• Status: Active Not Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 102 (estimated)
• Sponsor: Suez Canal University · Academic / Other
• Sex: All
• Age: 35 Years
• Healthy volunteers: Not accepted

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. 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.

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.

Conditions

• Knee Osteoarthritis

Interventions

Type	Name	Description
DEVICE	Transcranial Direct Current Stimulation (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.

Timeline

• Start date: 2025-12-20
• Primary completion: 2026-05-20
• Completion: 2026-06-01
• First posted: 2025-12-18
• Last updated: 2026-04-13

Locations

1 site across 1 country: Egypt