EVI-01-IT Safety Study

Inclusion Criteria: * Eighteen (18) years old or above; * Patient signed informed consent form; * Patients with stable symptoms related to knee osteoarthritis for at least 3 months prior to screening; * Failure, inadequate response or intolerance to analgesics and/or NSAIDs or low-grade opioids; * Kellgren-Lawrence radiographic stage: II-III diagnosed in the previous 12 months; * WOMAC average pain index score \> 40 mm and \< 90 (on a VAS 0-100 mm) on the knee to be treated; * Difference ≥ 10 mm between the WOMAC average pain score of the knee to be treated and WOMAC average pain score of the contralateral knee at screening; * Body Mass Index (BMI) inferior to 35 kg/m2 (weight/height). Exclusion Criteria: * Concomitant inflammatory joint disorder; * Had received previous visco-supplementation treatment in the study knee within 6 months or intra articular corticosteroids within 3 months\* prior to inclusion; * Infection in or around the study knee; * Relevant skin disease in the area of injection site; * Documented presence of injury or trauma of the study knee at screening, including evidence of a subchondral fracture, meniscal lesion, presence of bone or cartilage fragments in the study knee; * History of allergy or intolerance to sodium hyaluronate; * Documented presence of osteonecrosis in one or both knees; * Inability to understand the study procedure; * Participation in another clinical trial within 30 days prior to screening; * Ongoing therapy with daily dosage \> 101 mg of acetylsalicylic acid as part of cardiovascular preventive treatment. If dose \< 101 mg, it must be maintained during the study; * Pregnant or breast-feeding at inclusion. * 1 month = 30 days