Patients in the ACB group (Group I) will receive a single-shot adductor canal block under ultrasound guidance bupivacaine administered preoperatively.

Patients in the ACB + iPACK group (Group II) will receive a single-shot adductor canal block combined with an infiltration between the popliteal artery and the capsule of the knee (iPACK) under ultrasound guidance bupivacaine.

All patients in Group I will receive a preoperative adductor canal block. In all groups, an intravenous patient-controlled analgesia device containing morphine will be administered for postoperative pain management.

In the recovery room, all patients will given a patient- controlled analgesia device containing morphine 0.5 mg/ml, set to deliver a 1mg bolus dose of morphine with an 15 min lockout time and 4 mg 1 h limit.Total morphine consumption during the 24 hours postoperative period will recorded at 5 times intervals ( 2, 4, 6, 12, 24 hours).

A Research assistant, blinded to the group allocation, interviewed patients and collected data at 5 times intervals ( 2, 4, 6, 12, 24, hours) in the 24 hours postoperatively. Patients were asked to rate their pain using verbal analog scale, where 0= no pain and 10= worst pain possible.

incidences of nausea and vomiting during the 24 hours postoperative period will recorded at 6 time intervals ( 2, 4, 6, 12, 24 hours).