Intra-articular Polyacrylamide Hydrogel in Knee Osteoarthritis

Inclusion Criteria: * Men and women above 50 years; * Verified knee osteoarthritis in accordance with the ACR (knee pain combined with one of the following signs: age above 50 years, knee crepitus or morning joint stiffness lasting for less than 30 minutes combined with radiologic signs of knee osteoarthritis); * Kellgren Lawrence radiological grade II-III knee osteoarthritis with the predominant involvement of the medial tibiofemoral region of the knee joint; * Joint space width (JSW) of the target knee joint at least 2.5 mm. Exclusion Criteria: 1. History of any injury or surgical intervention on the target knee joint (except for diagnostic arthroscopy made not longer than 60 days at the study entry); 2. Severe degenerative changes in the target knee joint determined as the joint space narrowing less than 2 mm; 3. Varus or valgus deformation of the target knee joint; 4. Instability of the target knee joint; 5. Active inflammation of the target knee joint (edema, hyperemia, present effusion) at the study entry; 6. Microcrystalline arthropathies; 7. Systemic inflammatory disease (rheumatoid arthritis, systemic lupus erythematosus, etc.); 8. Seronegative spondyloarthritis and reactive arthritis; 9. Inflammatory diseases of the skin and soft tissues in the proposed injection site for the test MD or placebo in the target joint; 10. History of venous thrombosis and thromboembolia; 11. Coagulogram abnormalities (APTT, prothrombin time, prothrombin index, fibrinogen); 12. Inflammatory changes in the complete blood count (leukocytosis, increase of erythrocyte sedimentation rate \[ESR\]); 13. Platelet count abnormality (in accordance with the reference ranges of the local laboratory; 14. Increase of rheumatoid factor level; 15. Increase of uric acid level \> 360 μmol/l; 16. Diabetes mellitus; 17. Hemophilia and other hemorrhagic diatheses, as well administration of anticoagulants and disaggregants; 18. Positive results of HIV, HBs-Ag, anti-HCV, RW tests; 19. Intra-articular injection to the target knee joint: * Noltrex - within 24 months prior patient's inclusion to the study; * hyaluronates - within 6 months prior patient's inclusion to the study; * glucocorticosteroids - within 1 month prior the study inclusion; * non-steroidal anti-inflammatory drugs (NSAID) - within 3 weeks prior patient's inclusion to the study. 20. Oral administration of non-steroidal anti-inflammatory drugs (NSAID) within 2 weeks prior the study inclusion; 21. Necessity of systemic glucocorticosteroids in any dosage form; 22. Paracetamol administration within 48 hours prior the study inclusion; 23. Pregnancy and lactation; 24. Hypersensitivity to components of the test MD or placebo; 25. Severe liver disorder determined as the increase of one of the values: ALT, AST, ALP, total bilirubin, GGTP more than 3 times the upper limit of normal; 26. Renal diseases with the glomerular filtration rate estimated per Cockraft-Gault formula less than 60 ml/min/1.73 m2 (III-V stage chronic renal disease \[CRD\]); 27. Clinically manifest hip osteoarthritis; 28. History of knee and coxofemoral endoprosthesis; 29. Acute infectious diseases or infectious aggravations of chronic diseases (respiratory infections) within one month prior the study inclusion; 30. Severe decompensated chronic or acute diseases and other conditions which, by the opinion of the study physician, may preclude the patient's participation in the study or affect the study results.