Efficacy and Safety of Intraarticular Sodium Hyaluronate Single Injection in Patients With Osteoarthritis of the Knee

Inclusion Criteria: * Patient ≥ 45 years of age of either sex. * Primary knee OA of the medial or lateral femoro-tibial compartment documented according to ACR criteria with symptoms, at screening, from at least 3 months. * KL radiological grade 2-3. * Antero-posterior view X-Ray image of the target knee * Pain intensity at screening in the target knee ≥40 mm and \<80 mm measured by Visual Analogue Scale (VAS), and ≤ 20 mm in the contralateral knee. * Able to understand and willing to comply with study procedures. * Able to provide informed consent. Exclusion Criteria: * BMI ≥ 30 kg/m2. * Pregnant or lactating women. Women of child-bearing age not using effective contraception. * Severe inflammation of the target knee. * Previous surgery in the target knee, including arthroscopy. * Subjects with any musculoskeletal condition affecting the target knee that would impair the proper evaluation * Patients with joint inflammatory disease, microcrystalline arthropathies and significant osteoarthritis symptoms in other joints apart from the knee, and which require pharmacological treatment. * Underlying disease considered by the investigator that might interfere with the development and evaluation study. * Subjects with venous or lymphatic stasis in the relevant limb. * Previous administration of any of the following treatments: hyaluronic acid i.a. (last year); steroids i.a. or joint lavage (last 3 months), glucosamine sulfate, chondroitin sulfate or diacerein (last 3 months), NSAIDs (last 14 days), any investigational drug (last month) or its administration during this study. * Pain in other parts of the body greater than the knee pain that could interfere with the evaluation. * Any pathology that, under investigator judgement, interfere with the administration or assessment. * Patients with known hypersensitivity to SH or paracetamol. * Patients in waiting list for surgery. * Patients awaiting disablement assessment. * Previous participation in this protocol