Efficacy of Therapy With PRP Injections Versus HA in Patients With Advanced Grade of GONArthrosis

Inclusion Criteria: 1. Age ≥ 18 years ; 2. MRI confirmed grade III or IV unilateral gonarthrosis ; 3. Pain ≥ 3/10 on the visual analogue scale (VAS); 4. Patient with a BMI \< 35 5. Patient capable of giving consent prior to participation in the study; 6. Affiliated or entitled under a social security scheme. Exclusion Criteria: 1. Non-steroidal anti-inflammatory drugs\* or corticosteroids\*\* taken in the 7 days prior to inclusion; 2. Local injection of hyaluronic acid in the 2 months prior to inclusion; 3. Local injection of PRP within 1 year prior to inclusion; 4. Local injection of corticosteroids within 5 months prior to inclusion; 5. Current anticoagulant treatment that cannot be stopped during the hyaluronic acid or PRP injection protocol period; 6. Patient diagnosed with any type of cancer in the last 3 years; 7. Pregnant women, women in labour or breast-feeding women; 8. Patients under judicial protection (guardianship, curatorship, etc.) or safeguard of justice; 9. Any other reason which, in the opinion of the investigator, could interfere with the evaluation of the study objectives. * Acetylsalicylic acid is allowed when it is prescribed as an antiplatelet agent at doses lower than or equal to 160 mg per day. It has, indeed, no anti-inflammatory effect at these doses. * Corticosteroids can be administered when they have a local action different from the one applied to the treated knee (cutaneous, instiled or inhaled routes).