Hydrolyzed Collagen Formulation vs Placebo in Knee Osteoarthritis

Inclusion Criteria: 1. Unilateral involvement; 2. Signs and symptoms of degenerative pathology of knee cartilage; 3. Radiographic and MRI signs of degenerative pathology of the knee cartilage (Kellgren-Lawrence 1-4 grades); 4. Failure, defined as the persistence of symptoms, after at least one course of conservative treatment (pharmacological, physiotherapeutic or infiltrative treatment); 5. Ability and consent of patients to actively participate in clinical follow-up; Exclusion Criteria: 1. Patients who have undergone intra-articular injections of another substance in the previous 6 months; 2. Patients undergoing knee surgery within the previous 12 months; 3. Patients with malignant neoplasms; 4. Patients with rheumatic diseases; 5. Patients with diabetes; 6. Patients with hematologic diseases (coagulopathies); 7. Patients on anticoagulant therapy; 8. Patients with metabolic disorders of the thyroid gland; 9. Patients abusing alcoholic beverages, drugs or medications; 10. Body Mass Index \> 35; 11. Pregnant or lactating women. 12. Patients with established hypersensitivity to bovine collagen or vitamin C. 13. Patients with joint or peri-articular infections, emarto, erythema, or psoriatic patches in the knee joint area