The French Society of Rheumatology cannot rule on the value of intra-articular injections of PRP due to the lack of hindsight and insufficient data. In fact, the injection protocols are very heterogeneous in terms of preparation method, the presence or not of leukocytes, the number of centrifugations, the volume injected, the ultrasound guidance, which makes it difficult to analyze the literature. The investigator objective is therefore to evaluate the effectiveness of combined injections of PRP and hyaluronic acid.

Inclusion Criteria:

• age : > 18 years old
• Patients benefiting, in the context of knee osteoarthritis, from viscosupplementation alone or from two injections of PRP, in combination with HA, at the Amiens University Hospital.

Exclusion Criteria:

• Patient refusal to use the data
• Language barrier
• Age less than 18 years old.

Patients benefiting, in the context of knee osteoarthritis, from viscosupplementation alone or from two injections of PRP, in combination with HA, at the Amiens University Hospital.