Comparison Between Intra-articular Infiltrations of PRP, MFAT, and PRP-MFAT in the Treatment of Symptomatic Knee Osteoarthritis.

Inclusion Criteria: * Patients of both gender, between 20 and 75 year-old. * Symptomatics degenerativ or post traumatic chondropathy, on at least one of the 3 knee compartments ICRS grade 2, 3 or 4 with VAS\>4 and failure of well-conducted medical treatment for at least 1 year (palliative analgesics adapted to the pain, AINS, rehabilitation by a physiotherapist, injections intra-articulaires de corticoïdes et/ou d'acide hyaluronique) * Varus or valgus less than or equal to 5°. * BMI greater than 20 (in order to have sufficient fatty tissue) * Informed consent signed by the patient * HB \> 10g/dl * Negative beta-HCG at inclusion and effective contraception for patients of childbearing age, for 1 month. * Beneficiaries of or affiliated to a social security system Exclusion Criteria: * Contraindications to MRI : ocular foreign bodies, pacemaker, neurostimulator, cochlear implant, vascular clips, metallic heart valve * Body mass index (BMI) of less than 20 kg/m2 not allowig to obtain a sufficient quantity of adipose tissue. * Thrombocytopenia \< 150 G/L * Thrombocytosis \> 450 G/L * Known thrombopathy * TP=\> PR \< 70%. * TCA=\> APR \> 1.20s * Anemia HB \< 10g/dl * Positive markers for the following active infectious diseases: HIV 1 and HIV 2 human immunodeficiency virus infection; HTLV I and II virus infection; Hepatitis B virus infection; Hepatitis C virus infection; Syphilis causative agent infection. * Use of antiplatelet agents, aspirin, anti-vitamin K drugs for less than 15 days. * Chronic treatment with oral corticosteroids or the use of such treatment less than 2 weeks prior to inclusion * Intra-articular corticosteroid injection less than 2 months prior to inclusion * Intra-articular injection of hyaluronic acid less than 2 months prior to inclusion * Non-steroidal anti-inflammatory drugs less than 15 days prior to inclusion * Recent fever or infection (bacterial or viral) less than one month old * Autoimmune diseases * Inflammatory arthritis * Immune deficiency * Ongoing or chronic infectious diseases (viral or bacterial) * T Malignant tumours or history of malignant tumours less than 5 years prior to inclusion * Pregnant or lactating women * Adults protected by law (guardianship or curatorship) * Patient participating simultaneously in another research project involving the human person * Minors * Persons residing in a health or social institution * Persons in emergency situations * Persons deprived of liberty * Persons not covered by the French social security scheme * Contraindication to local anesthesia and/or surgery * Allergy to local anesthetics * Inmates