The purpose of this study is to evaluate the efficacy of bio-optimized curcumin(Flexofytol) during a 90-days period in knee ostearthritis patients on the serum levels of specific biomarkers of osteoarthritis and on the evaluation of pain.

Inclusion Criteria:

• 45 to 80 years of age
• Internal femorotibial gonarthrosis responding to the clinical and radiological criteria of ACR
• Symptomatic knee for more than 6 months
• Mean knee pain on the last 24 hours of at least 40 mm on VAS
• Kellgren & Laurence grade II to III
• Patients able to avoid NSAIDs and analgesics during the study
• Patients having signed informed consent
• Patients able to follow the study instructions

Exclusion Criteria:

• Related to the osteoarthritis pathology:

  • Osteoarthritis linked to a metabolic arthropathy
  • Predominant associated symptomatic femoropatellar osteoarthritis
  • Chondromatosis or villonodular synovitis of the knee
  • Recent trauma (< 1 month) of the knee responsible for the pain
  • Inflammatory flare
  • Pathology potentially interfering with the evaluation (metabolic inflammatory arthropathy, rheumatoid arthritis, lower limb radiculalgia, arthritis...
  • Paget disease
  • Homolateral coxarthrosis
  • Articular Prosthesis
  • Knee joint effusion

• Related to previous and associated treatments:

  • Corticosteroids injection in the previous month, whatever the joint concerned,
  • Hyaluronan injection in the evaluated knee during the previous 6 months,
  • NSAID or analgesics in the 72 hours prior to inclusion
  • No modification of Slow-acting drugs for OA and/or dietary supplements taken within less than 6 months prior to the study(ex: chondroitin sulfate, diacerein, soy and avocado unsaponifiables, oxaceprol, granions de cuivre, glucosamine, phytotherapy for OA, homeopathy for OA...),
  • Anticoagulant (coumarinic) treatment and heparin
  • General corticotherapy,
  • Contraindication to paracetamol.

• Related to associated pathologies:

  • Patient suffering from serious associated illness (liver failure, kidney failure, non-controlled cardiovascular diseases...)

• Related to patients:

  • Pregnant or breastfeeding women
  • Pre-menopausal women with no contraception
  • Patients unable to write
  • Patients enrolled in a clinical trial in the previous 3 months
  • Patients under juristic protection or under guardianship.