The aim of this study is to compare between the post-operative analgesic effect of two approaches of transmuscular quadratus lumborum block (transverse versus paraspinous sagittal transmuscular QLB) in total hip replacement surgery.

During the preanesthetic assessment, all patients will be educated about the visual analogue scale (VAS) for pain assessment, with scores ranging from 0 to 10 (0 represent no pain, while10 represent maximum intolerable pain).

The patients will be randomly classified into three equal groups (25 patients each). Group allocation will be done by computer generated random numbers and closed opaque sealed envelopes. The study will be designed to be double blind as all patients and postoperative assessor will be blinded to group assignment.

Patients will be randomized to one of three equal groups:

• Group I: Control group (n= 25 patients): Patients in this group will receive ipsilateral sham ultrasound-guided block via subcutaneous injection of 1 ml of normal saline after surgery.
• Group II (n= 25 patients): Patients in this group will receive an ipsilateral single shot of transverse transmuscular approach of QLB (30 ml of plain bupivacaine 0.25%) after surgery using ultrasonographic guidance.
• Group III (n= 25 patients): patients in this group will receive an ipsilateral single-shot of paraspinous sagittal approach of QLB (30 ml of plain bupivacaine 0.25%) after surgery using ultrasonographic guidance.

Inclusion Criteria:

• 75 patients, aged between 21- 80 years old, of both sex American society of Anesthesiology I - III scheduled for total hip replacement surgery.

Exclusion Criteria:

• Patient refusal.
• Coagulopathy
• Spinal deformities
• Peripheral neuropathy; sensory disorders in the leg requiring surgery and chronic pain.
• Mental dysfunction, psychiatric illnesses and cognitive dysfunction.
• History of drug abuse &chronic analgesic use