This is a prospective, long-term, observational, all-comers, open-label, multi-centre clinical investigation enrolling subjects with knee osteoarthritis who is eligible for treatment with Arthrosamid® according to the Instruction for Use.

This is a prospective, long-term, observational, all-comers, open-label, multi-centre clinical investigation enrolling subjects with knee OA who is eligible for treatment with Arthrosamid® according to the Instruction for Use (IFU).

All subjects will be followed over an observational period of five years with yearly follow-up check points. The first follow-up visit should be six months after the treatment. All follow up visits can be performed as telephone visits.

Inclusion Criteria:

• Stated willingness to comply with all study procedures and availability for the duration of the study
• Male or female, aged ≥ 18 years
• Clinical diagnosis of knee OA

Exclusion Criteria:

• 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 manufacturer's information for the specific product, before injection with Arthrosamid®
• If the patient has previously received treatment with a different non-absorbable injectable/implant
• If the patient has received a knee alloplasty or has any foreign material in the knee
• If the patient has undergone knee arthroscopy within the last 6 months
• If the patient has haemophilia or is in uncontrolled anticoagulant treatment

Patients will be recruited from participating rheumatology or orthopedic centers.