Efficacy of Hyaluronic Acid and Platelet-rich Plasma Combination in Knee Osteoarthritis

Inclusion criteria: * Knee pain for 4 months; * Knee degenerative sign evaluated with X-ray with a Kellgren-Lawrence grade inferior to 3; * Patients able to understand the study conditions and willing to participate for its entire duration; * Patients who signed written informed consent. Exclusion criteria: * Severe knee osteoarthritis of grade 4; * Diabetes mellitus; * Rheumatoid arthritis; * Ongoing malignancies; * Certified allergic reactions towards the administered drugs ; * Malalignment of mechanical axis of the lower limb (varus \> 10 °, valgus \> 10 °); * Coagulopathies; * Severe cardiovascular diseases; * Ongoing infections; * Immunodepression; * Anticoagulants or anti-platelet agents; * Haemoglobin \< 11 g/dl; * Platelet count \< 150,000/mm\^3 * Drug addiction; * Alcoholism; * Psychiatric disease; * Pregnancy or breastfeeding.