Long-term Safety and Performance of KiOmedine CM-Chitosan Supplementation in Advanced Symptomatic Knee Osteoarthritis

Inclusion Criteria: * Male or female aged ≥ 40 years and ≤ 85 years. * Advanced osteoarthritis, involving one or multiple of the following phenotypes: tricompartmental osteoarthritis, isolated or severe patella-femoral osteoarthritis, a BMI ≥ 30 kg/m2, and/or a Kellgren and Lawrence grade III or IV classification: * Patellofemoral osteoarthritis referring to symptoms, including pain, that are principally of patellofemoral origin (Patellar syndrome). * Radiological Kellgren and Lawrence grade III to IV from a standing knee radiograph taken less than 6 months previously. * Symptomatic osteoarthritis diagnosed via radiographic assessment and according to the clinical and radiological criteria of the American College of Rheumatology (ACR). * Single intra-articular corticosteroid injection during the screening visit (V0), according to standard clinical practice, to resolve clinically apparent knee effusion and/or local signs of inflammation. Patients can only participate in the clinical investigation when there is no sign of effusion and no local signs of inflammation at the patient in visit (V1) which is planned 1-2 weeks after the screening visit. * Moderate to severe symptomatic pain (i.e., total score on the WOMAC pain subscale ≥12) at screening visit in the treatment knee not or poorly responding to first line non-opioid analgesics and non-steroidal anti-inflammatory drug in oral uptake. * Pain criteria assessed prior to injection using the 5-point Likert WOMAC pain score: * Treatment knee: moderate to severe pain in the most affected knee (i.e., total score on the WOMAC pain subscale ≥12). * Non-treatment knee: no to mild pain in the less/non affected knee (i.e., total score on the WOMAC pain subscale ≤5). * Fully ambulatory patient for functional evaluation. * For female NOT surgically sterile (tubal ligation or hysterectomy) or NOT postmenopausal for at least one year, must have an effective contraception (pill, patch, ring, diaphragm, implant or intrauterine device). * Able to understand and follow the instructions of the study. * Having signed a written informed consent. Exclusion Criteria: Meeting one of the following contraindications as stated in the instructions for use of KiOmedine® CM-Chitosan or Synvisc® One: * A known allergy or hypersensitivity to any of the product components, * Infections or skin disease at or around the injection site, * Severe inflammation, synovitis or inflammatory arthritis of the knee joint, * A history of autoimmune and crystal diseases, * Evidence of lymphatic or venous stasis or serious blood disorders.