GonarthrosisPhase 2INDIGONCT07668674
Functional Brain MRI to Understand Pain Phenotypes in Knee Osteoarthritis
A Phase 2 study testing blood sampling and Resting-state functional MRI in people with Gonarthrosis and Neuropathic Pain, Nociceptive Pain, run by University Hospital, Clermont-Ferrand at 3 sites in France.
Trial summary
Some people with knee osteoarthritis (gonarthrosis) experience pain differently. In some, the pain is described as "nociceptive" (directly related to the joint), while in others it has "neuropathic" characteristics (related to nerve function). Read more about this study
- Who is it for?
- Ages 40 years and older, women only
- Conditions the study is for
- Gonarthrosis, Neuropathic Pain, Nociceptive Pain
- What is being tested?
- blood sampling and Resting-state functional MRI
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 60 participants
- Where
- 3 sitesFrance
- Study dates
- Jul 2026to Aug 2028
- Phase
- Phase 2
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 40 years and older
- Women only
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Women aged 40 or older (only women will be included to ensure consistency in the analyses, given the higher prevalence of osteoarthritis in women and the influence of sex/gender on the experience of pain)
- Diagnosis of femorotibial osteoarthritis of the knee according to the 1986 American College of Rheumatology criteria
- Presence of knee pain with an intensity of ≥ 4/10 on a numerical rating scale (NRS)
- Chronic knee pain, i.e., lasting at least 6 months with at least 15 days of pain in the past 30 days
- Completion of the PainDETECT questionnaire, which will allow the patient to be assigned to one of two groups prior to the enrollment visit (those with nociceptive pain [score ≤ 12] and those with neuropathic pain [score > 13])
- Patients have read and understood the information letter
- Patients have signed the informed consent form
- Patients are enrolled in a social security program
Who cannot join
- Other joint diseases affecting the knees (gout, chondrocalcinosis, rheumatoid arthritis, spondyloarthritis, psoriatic arthritis)
- Conditions that, in the investigator's opinion, interfere with the assessment of osteoarthritic pain, such as conditions causing neuropathic pain in the lower extremities (e.g., peripheral neuropathy, chronic radiculopathy) or fibromyalgia
- Kellgren-Lawrence radiographic stage IV in one or both knees
- Patients with one or more knee prostheses
- Claustrophobia making MRI impossible
- Contraindication to MRI
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- Pregnant or breastfeeding women
- Patients under guardianship, conservatorship, deprived of liberty, or under judicial protection
- Patients who have participated in an interventional clinical trial within the last 6 months that could impact the primary endpoint
Trial locations and contacts
3 sites in 1 country. Contact the study team or a site near you to ask about taking part.
France3 sites
CHU Clermont-Ferrand
Clermont-Ferrand
Lise Laclautre, 0473754963, promo_interne_drci@chu-clermontferrand.fr
Sylvain MATHIEU
APHP - Pitié-Salpêtrière
Paris
Florian BAILLY, +33142161194, Florian.bailly@aphp.fr
Florian BAILLY
APHP - Saint-Antoine
Paris
Jérémie SELLAM, +33149282520, Jeremie.sellam@aphp.fr
Jérémie SELLAM
About this study
Official title: Functional Brain MRI to Understand Pain Phenotypes in Knee Osteoarthritis: a Multicenter Comparative Pilot Study
Some people with knee osteoarthritis (gonarthrosis) experience pain differently. In some, the pain is described as "nociceptive" (directly related to the joint), while in others it has "neuropathic" characteristics (related to nerve function).
The goal of this multicenter, cross-sectional and comparative study is to compare resting brain activity in a brain region called the anterior insula among female patients with painful knee osteoarthritis who experience nociceptive pain compared to those with neuropathic pain.
Read more
Researchers will compare brain activity at rest between these two types of pain in women over 40 with painful knee osteoarthritis. A better understanding could help improve pain management in the future.
Participants will be asked to :
- complete questionnaires during the inclusion visit and on the day of the scan,
- undergo a clinical examination and a blood test at the inclusion visit,
- undergo a functional MRI (fMRI), an imaging test that allows observation of brain activity at rest.
Paticipants in the study does not involve any additional treatment. the fMRI scan is non-invasive and does not require any injections.
Read the detailed description
This study will include patients with painful knee osteoarthritis (pain scoring ≥ 4/10 on the Numerical Rating Scale (NRS)). Patients matched by age (within 3 years) will be divided into two groups based on their PainDETECT score: those with nociceptive pain (score ≤ 12) and those with neuropathic pain (score > 13).
Participants will be recruited from three rheumatology centers (30 in Clermont-Ferrand, 15 at Saint-Antoine Hospital, and 15 at Pitié-Salpêtrière Hospital in Paris). The rheumatologist will verify eligibility and provide information during the pre-enrollment consultation, within 30 days prior to enrollment. After obtaining their informed consent, patients will attend the enrollment visit and be assigned to a group based on their PainDETECT score.
Each participant will undergo a clinical evaluation, including the following PRO measures: Lequesne and WOMAC functional indices, EuroQol EQ-5D, Hospital Anxiety and Depression Scale, fatigue and pain intensity scales, Catastrophizing Scale (PCS), ICOAP, OASIS, and Flare-OA scales. A QST test will also be performed using the Neogi method, which includes pressure pain thresholds, conditioned pain modulation, and temporal pain summation.
A blood test will be performed, including high-sensitivity CRP and metabolic markers (lipid profile, HbA1c, and fasting blood glucose), due to the link between metabolic syndrome and osteoarthritic pain.
Within 30 days of enrollment, participants will undergo an fMRI scan at the radiology department in Clermont-Ferrand or at La Pitié-Salpêtrière. On the day of the scan, participants will complete additional self-reports of knee pain using the questionnaires. Interpretation of the fMRI data will be centralized in Clermont-Ferrand.
- Conditions
- Gonarthrosis, Neuropathic Pain, Nociceptive Pain
- Being tested
- blood sampling, Resting-state functional MRI
- Keywords
- Gonarthrosis, Neuropathic pain, Nociceptive Pain, Functional MRI, Anterior insula, Brain activity in the anterior insula at rest, INDIGO
- Medical subject headings
- Osteoarthritis, Knee, Neuralgia, Nociceptive Pain
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
blood samplingBiological
Blood sampling will be performed at the inclusion visit. A biological assessment will include high sensitivity C reactive protein (hs-CRP) and metabolic markers (lipid profile, HbA1c, and fasting glucose). Additional blood samples (4 tubes) will be collected for biobank, including plasma and serum storage for the measurement of inflammatory markers.
Resting-state functional MRIProcedure or surgery
Resting-state functional brain MRI will be performed at Visit 2 (within 30 days of the screening visit). Participants will undergo a brain MRI acquisition at rest to evaluate anterior insula activity and functional connectivity with pain-related brain regions.
| Study group | Role | What they receive |
|---|---|---|
| Nociceptive pain knee osteroarthritis | Other | Participants with painful knee osteoarthritis classified as having nociceptive pain based on PainDETECT questionnaire score ≤12. Receives: Biological: blood sampling; Procedure: Resting-state functional MRI |
| Neuropathic-like pain knee osteoarthritis | Other | Participants with painful knee osteoarthritis classified as having neuropathic-like pain based on PainDETECT questionnaire score >13. Receives: Biological: blood sampling; Procedure: Resting-state functional MRI |
What is being measured
The primary outcome is the main question the study is designed to answer.
Resting-state anterior insula activity measured by functional MRI (BOLD signal amplitude)
Comparison of resting-state anterior insula brain activity between patients with painful knee osteoarthritis with nociceptive pain and those with neuropathic-like pain, classified using the painDETECT questionnaire.
Measured: At Visit 2 : within 30 days after inclusion, following Visit 1
Secondary outcomes (3)
Functional connectivity of the anterior insula with pain-related brain regions (resting-state MRI)
Functional connectivity between the anterior insula (seed region) and predefined pain-related brain regions (S1, M1, posterior incula, ACC, MCC, vmPFC, DLPFC, thalamus) will be quantified using seed-basing resting-state fMRI analysis.
Connectivity values will be expressed as Fisher-transformed correlation coefficients (z-scores).
Measured: At Visit 2 : within 30 days after inclusion
Correlation between clinical pain scores ans anterior insula activity (resting-state fMRI)
Correlation between clinical pain measures collected at visit 1 (painDETECT score, BAS pain intensity, WOMAC pain subscale, ICOAP score) and anterior insula activity measured at visit 2.
Anterior insula activity will be quantified using the beta coefficient from the general linear model (GLM) of resting-state fMRI.
Measured: Clinical measures at Visit 1 and imaging measures at Visit 2 (within 30 days after inclusion)
Correlation between clinical pain scores ans anterior insula functional connectivity (resting-state fMRI)
Correlation between clinical pain measures collected at visit 1 (painDETECT, VAS, WOMAC, ICOAP) and functional connectivity z-scores between the anterior insula ans pain-related brain regions measured at visit 2.
Measured: Clinical measures at visit 1 ; imaging at visit 2 (within 30 days after inclusion)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted25 Jun 2026
- Study startJul 2026 (estimated)
- Primary completionAug 2028 (estimated)
- Study completionAug 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for GonarthrosisStudies 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 2
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 60 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University Hospital, Clermont-Ferrand
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Sylvain MATHIEU, Principal investigator, University Hospital, Clermont-Ferrand
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07668674
- Sponsor's protocol ID
- AOI 2025 MATHIEU
- Other IDs
- 2025-A02366-43
- Acronym
- INDIGO
- Status last verified
- Apr 2026
- First submitted
- 24 Apr 2026
- Last updated
- 25 Jun 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No