The study is, in accordance with current legislation, definable as monocentric Prospective Observational. The primary outcome will be blood loss calculated on the basis of hemoglobin (Hb) on the third postoperative day. adult patients who will undergo surgery of hip arthroplasty. Patients will undergo: Preoperative T0: clinical visit/medical history, completion of the VAS questionnaire, Blood sampling to assess hemoglobin values Operative T1: hip arthroplasty surgery using one of the surgical approaches routinely used within our Institute T2 - Postoperative at 1 day from T1: VAS questionnaire, evaluation of any Adverse events T3 - Postoperative at 3 days from T1: blood loss based on the values of hemoglobin (Hb), assessment of any adverse events, and VAS questionnaire T4- Post operative at 45 days +/- 10 days from T1: evaluation of any events adverse, follow-up visit.