Daily Activity and Clinical Outcome Measurement of Arthrosamid® Administration in Symptomatic Knee Osteoarthritis.

Inclusion Criteria: * Subjects \> 18 years of age at the time of injection * Advanced osteoarthritis, involving one or multiple of the following phenotypes: tricompartmental osteoarthritis, isolated or severe patella-femoral osteoarthritis, and/or a Kellgren and Lawrence grade II or III classification: * Patellofemoral osteoarthritis referring to symptoms, including pain, that are principally of patellofemoral origin (Patellar syndrome). * Radiological Kellgren and Lawrence grade II to III from a standing knee radiograph taken less than 6 months previously. * Subjects with a normal BMI ≥ 18.5 kg/m² and \< 30 kg/m² * Symptomatic osteoarthritis diagnosed via radiographic assessment and according to the clinical and radiological criteria of the American College of Rheumatology * Fully ambulatory patient for functional evaluation. * 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 (IFU) of Arthrosamid®: * If an active skin disease or infection is present at or near the injection site * If the joint is infected or severely inflamed * If a degradable intra-articular injectable such as hyaluronic acid is present, it must be expected to be absorbed according to the manufacturer's information for the specific product, before injection with Arthrosamid® * Other medical conditions contributing to the rehabilitation process of the injection according to the surgeon * Important medical conditions such as, Parkinson's Disease, dementia, multiple sclerosis and cerebral vascular accident, which can disturb the patient's rehabilitation after injection according to the surgeon * Patient is participating in another clinical trial or has participated in a clinical trial in the last three months * Patients who did not met all the inclusion criteria