This study is a prospective, monocentric, interventional post-market study evaluating the effects of a single intra-articular injection of Arthrosamid in patients with symptomatic knee osteoarthritis. Arthrosamid is a polyacrylamide hydrogel consisting of 97.5% sterile water and 2.5% cross-linked polyacrylamide that integrates into the synovial tissue and is used for the symptomatic treatment of knee osteoarthritis.

The study will include 30 eligible patients receiving a single Arthrosamid injection and will be followed for up to 12 months. The primary objective is to evaluate the performance of Arthrosamid in terms of daily activities and clinical outcomes in patients with symptomatic knee osteoarthritis. The primary endpoint assesses the percentage change from baseline in daily activity levels at 6 months after injection, measured using an activity tracker combined with a digital rehabilitation tool. Additional assessments include patient-reported outcome measures and clinical follow-up visits conducted as part of standard care.

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