This prospective randomized controlled trial aims to examine the effect of fascia iliaca compartment block on the postoperative pain and opioid consumption in pediatric patients (3y≤ age \<18y) who will undergo orthopedics surgery (proximal femoral osteotomy). Patients will be allocated to either the FICB(Fascia iliaca compartment block + IV PCA) group or the control group (no block + IV PCA). Fascia iliaca compartment block will be performed using 0.25% ropivacaine (1mL/kg, MAX 30mL) under ultrasound-guidance at the end of surgery. The total opioid consumption at 12, and 24 hours after the surgery, and the pain score at 10 min after PACU admin, 1,6,24 hours after the surgery, the total dose of additional rescue analgesia (intravenous ketorolac or nalbuphine) at 12 and 24 hours after the surgery will be recorded.