Comparative Study of Two Hyaluronic Acid Formulation in the Management of Knee Osteoarthritis

Inclusion Criteria: 1. Female and male subjects ≥ 40 and ≤ 75 years of age 2. Body mass index (BMI) ≥20 and \<35 kg/m2 3. Tegner score ≥3 4. Subjects with primary knee OA of the medial or lateral femorotibial compartment with symptoms at screening and for at least 3 months prior to screening according to American College of Rheumatology (ACR) criteria and who have not responded to conservative non-pharmacologic treatment or simple analgesic regimens 5. Subjects with Kellgren-Lawrence (K-L) radiological grade 2 or 3 in the target knee 6. Subjects with at least one X-Ray image of the target knee taken at screening or within 6 months prior to the screening. 7. Subjects with OA pain intensity meeting the criteria below: * Subjects demonstrating at both the screening (V0) and the baseline (V1) visit, pain intensity in the target knee of 2 - 3 and in the contralateral knee 0 as measured by the WOMAC LK3.1 A1 Pain subscale (walking on a flat surface) 8. Willingness to discontinue oral and topical analgesics including NSAIDs and accept "rescue" paracetamol as the only medicine for joint pain prior to the injection and throughout the study. "Rescue" medication will be discontinued 24 hours before any study visit 9. Subjects able to understand and willing and able to comply with study procedures 10. Subjects able to provide informed consent 11. If female of childbearing potential, must have a negative pregnancy test at screening and agree to use a reliable form of contraception throughout the study\*. Note: To be considered of non-childbearing potential, females must be surgically sterile or postmenopausal for at least 1 year. \*Highly effective birth control methods include: combined hormonal contraception containing estrogen and progestogen) associated with inhibition of ovulation (oral, intravaginal, transdermal); progestogen-only hormonal contraception associated with inhibition of ovulation (oral, injectable, implantable); intrauterine device (IUD); intrauterine ormone-releasing system (IUS); bilateral tubal occlusion; vasectomised partner; sexual abstinence. Exclusion Criteria: 1. Inability to perform a 50-foot walk test 2. Subjects with secondary (post-traumatic) knee OA of the target joint 3. Subjects with K-L radiological grade 1 or 4 in the target knee 4. Subjects with known X-ray findings of acute fractures, severe loss of bone density, avascular necrosis, and /or severe bone or joint deformity in the target knee 5. Clinically apparent tense effusion of the target knee on examination (determined by either a positive bulge sign or ballottement of the patella (patellar tap)) 6. Subjects with osteonecrosis of either knee 7. Subjects with a history of knee joint replacement or arthroplasty of the target knee 8. Subjects with a history of arthroscopy of the target knee in the past 6 months 9. Subjects with a history of osteotomy or surgery of the target or contralateral knee and any other weight-bearing joint that would have interfered with knee assessment 10. Subjects with acute, recurrent synovitis, or any inflammatory conditions in the target knee 11. Subjects with any significant injury to the target knee in the last 6 months (as per Investigator judgment) 12. Subjects with any musculoskeletal condition affecting the target knee that would impair the proper assessment of the Investigational Medical Device (IMD) performance in the target knee as assessed by the Investigator such as: 1. severe varus/valgus deformity (\>15°) 2. predominantly patellofemoral pain syndrome 13. Subjects with health condition associated with pain which may interfere with study variables evaluation 14. Subjects with a known history or present evidence of conditions which may affect the target knee assessments, like rheumatic disease, lupus arthropathy, infective or metabolic joint diseases; recurrent clinical chondrocalcinosis; crystal arthropathies; osteoarticular pathologies differing from arthrosis; acromegaly; haemochromatosis; Wilson's disease; primary osteochondromatosis; heritable disorders; collagen gene mutations 15. Subjects with gout or calcium pyrophosphate (pseudogout) diseases of the target knee with flare-ups within 6 months prior to screening 16. Subjects with fibromyalgia, pes anserine bursitis, lumbar radiculopathy and/or neurogenic or vascular claudication 17. Subject with significant anterior knee pain due to the diagnosed isolated patellar-femoral syndrome or chondromalacia in the target knee 18. Subjects with symptomatic OA of the hips, spine or ankle that interferes with the evaluation of the target knee 19. Subjects with venous or lymphatic stasis in the relevant limb 20. Subjects with a history of the following treatments: 1. IA corticosteroids in any joints in the past 3 months 2. Systemic (both oral and parenteral) and topical corticosteroids at the target knee in the past 30 and 90 days, respectively 3. Topical anti-inflammatory agents and analgesics applied at the target knee in the past 48 hours 4. Viscosupplementation with hyaluronic acid or joint-lavage in the target knee in the past 6 months 5. Physical therapy started in the past 3 months in the target knee. Subjects having started a physical therapy from more than 3 months can take part in the study 6. Change in the dosage of symptomatic slow-acting supplements for OA such as glucosamine, chondroitin sulfate, diacerhein, or other supplements such as avocado or soya extracts, etc. in the last month 7. Chronic or recurrent use of narcotic analgesics 21. Subjects with a history of chronic or recurrent use of NSAIDs/analgesics/narcotics because of diseases different from OA of the target knee 22. Subjects treated with agents which alter the perception of pain such as hypnotics, muscle relaxants, anxiolytics if the intake has started less than 8 days before screening 23. Subjects with a history of recurrent severe allergic or immune-mediated reactions or other immune disorders 24. Subjects with vascular insufficiency of lower limbs or peripheral neuropathy severe enough to interfere 25. Subjects with active liver disease 26. Subjects with any clinically significant laboratory values which, based on investigator judgment and subject clinical history, may affect study evaluation 27. Subjects who currently use heparin or anti-vitamin K (e. g. crystalline warfarin) anticoagulant therapy 28. Subjects with infections, wounds, bruising, disease or trauma in the area of the injection site or joint 29. Subjects with suspected or known history of hypersensitivity to paracetamol, lidocaine, hyaluronic acid or to hyaluronate preparations or gram-positive bacterial proteins 30. Subjects with any surgical procedures scheduled in the next 6 months 31. Subjects who have participated in a clinical study or investigation in the last 3 months 32. Pregnant or lactating women, and women of childbearing potential unwilling to use adequate contraception and conduct a pregnancy test at screening.