The aim of the study is to compare the efficacy up to 12 months of two different types of PRP (PRP with leukocytes vs PRP depleted of leukocytes) in the echo-guided infiltrative treatment of hip OA by including 230 patients in the study and evaluating them through subjective (using the WOMAC score as the primary outcome) and objective clinical scores.

Platelet-rich plasma (PRP) has recently emerged as an attractive biological approach to address joint degeneration. It has gained increasing attention because of the high concentration of growth factors, cytokines, and bioactive molecules stored in platelet-rich α-granules, which have been shown to participate in joint tissue homeostasis, being involved in both healing processes and immunoregulation and modulation of inflammation. Several preparation methods are available for PRP, which can give products with different compositions and characteristics.The presence of leukocytes is one of the most debated aspects of PRP efficacy, and is used as one of the main discriminators to distinguish different PRPs.

Patients with OA of the hip will be included in a randomized controlled, double-blind trial, in which one group of patients will be treated with 3 infiltrations of PRP with leukocytes and one group will be treated instead with 3 infiltrations of PRP without leukocytes. A total of 230 patients will be included and will undergo infiltrative treatment after collecting informed consent for study participation. Patients will be clinically evaluated before the injection procedure and at 2-6-12 months after treatment by the medical staff.

Inclusion Criteria:

• Signs and symptoms of hip OA (pain intensity of at least 4 points and not more than 8 of VAS pain - 0-10 scale in the previous week);
• Radiographic signs of hip OA (Grade 1-2 according to Tonnis classification) or MRI signs (chondropathy or minimal labrum degeneration without acute lesions) even if Grade 0.
• Unilateral involvement; Hemoglobin > 11 g/dl;
• Platelet count > 150,000 plt/mm3 (Recently performed CBC examination);
• Negative serological tests for HBsAg, HCV Ab, HIV-1-2 Ab
• No clinically significant electrocardiographic changes (Recently performed ECG).
• Ability and consent of patients to actively participate in clinical follow-up;- Signature of informed consent.

Exclusion Criteria:

• Patients unable to express consent;
• Patients undergoing infiltration of other substance in the previous 6 months;
• Patients undergoing lower limb surgery to be treated in the previous 12 months;
• Patients with malignant neoplasms;
• Patients with rheumatic diseases;- Patients with uncontrolled diabetes;-Patients with hematological diseases (coagulopathies);
• Patients on anticoagulant-antiaggregant therapy that cannot be discontinued for at least 3 days prior to blood collection;
• Patients with uncontrolled thyroid metabolic disorders;
• Patients abusing alcoholic beverages, drugs or medications;
• Body Mass Index > 30;
• Patients who have taken NSAIDs in the 3 days prior to blood draw;
• Patients with cardiovascular disease for whom 300 ml blood draw would be contraindicated;
• Patients with recently performed CBC examination with Hb< 11 g/dl and Platelet values < 150,000 plt/mm3.
• Positive serological tests for HBsAg, HCV Ab, HIV-1-2 Ab
• Pregnant and/or fertile women.
• Pain intensity less than 4 points or greater than 8 in accordance with the VAS scale.
• Patients with other hip pathologies: acetabular protrusion, concentric migration of the femoral head, presence of excessive deformity resulting from acetabular or femoral head dysplasia, collapse deformity, and deformed femoral head sequelae of Perthes disease or osteonecrosis of the femoral head.
• Previous extensive surgery of the reference joint (osteotomy around the hip, open or arthroscopic osteochondroplasty for femoro-acetabular conflict).

This is a double-blind randomized controlled trial with allocation 1:1. Patient blinding will be provided during the injection treatment.