Platelet-rich Plasma in Symptomatic Knee Osteoarthritis

Inclusion Criteria: * Age between 40 and 79 * Symptomatic knee OA according to ACR criteria evolving for more than 3 months * Predominantly femoro-tibial pain * KL 2 or 3 on femorotibial compartment on X-rays of less than 6 months * ENS ≥ 40/100 (with or without usual analgesic treatments) * Failures or contraindications to conventional treatments (analgesics, NSAIDs) * Patient able to understand the requirements of the trial and having signed a free and informed consent before entering the study * Patient able to read and understand written instructions * Patient able to complete the self-questionnaires * Use of effective contraception in premenopausal women Exclusion Criteria: * Other pathologies of the lower limbs interfering with the evaluation of knee osteoarthritis (symptomatic hip OA, Lumbar pain…) * Symptomatic contralateral knee OA with NRS ≥ 40/100 * Predominant patellofemoral symptoms * Radiographic knee OA stage 1 or 4 of KL * Predominant radiographic patellofemoral OA * History of target knee surgery with material * History of inflammatory or microcrystalline rheumatism * History of fibromyalgia * Morbid obesity (BMI\> 40kgs / m2) * Inflammatory flare (KOFUS score ≥ 7) * Use of opioids in the month prior to inclusion * Patient refusing to stop NSAIDs during the study and conventional analgesics 48 hours * History of infection of the target knee * Presence of chondrocalcinosis on the frontal x-ray * Previous PRP injection * Injection of HA or CS into the target knee during the last 3 months * History of hemostasis disorders or taking a curative dose of anticoagulant * Treatment with antiplatelet agents \[Acetylsalicylic acid (Aspegic, Kardegic, Duoplavin, Resitune, Asasantine), Clopidogrel (Plavix, Duoplavin), Dipyridamole (Persantine, Cleridium, Asasantine)\] * Haematological disease in progress or in remission for less than 5 years (malignant hemopathies, myelodysplasia, autoimmune thrombocytopenia) * Thrombocytopenia (\<150,000 platelets) * Patient undergoing treatment with chemotherapy or immunosuppressive drugs * Infection at the time of inclusion (bacterial infection and / or presence of fever and / or taking antibiotics) * Participation in a clinical trial on knee osteoarthritis during the last year * Participation in any clinical trial completed less than 3 months ago * Patient whose mental state does not allow him to understand the nature, objectives and possible consequences of the study * Patient under legal protection (curatorship or guardianship) * Pregnant woman or planning to become pregnant during the study or breastfeeding