lumbosacral plexus block (LSPB) has been widely applied in orthopedics departments due to its advantages, including reduction in the application of opiates, decreasing the occurrence of acute pain, promoting early activation, and shortening the time of hospital stay. LSPB is a peripheral regional technique of anesthesia and analgesia, that provides a block of the main components of the lumbosacral plexus.

Traditional ultrasound-guided lumbar plexus block combined with sacral plexus block requires separate blocks at different sites, requiring the lateral decubitus or prone position, which may be suboptimal in patients with severe pain. we present an anterior approach for combined lumbar and sacral plexus blocks with a one-point puncture.

Inclusion Criteria:

• ASA I-II.
• patients scheduled for unilateral femur or tibial surgery necessitate knee joint intervention
• patients who have severe pain hindering changing their position or patients who have spinal fractures or refusing spinal anesthesia.
• patients with the capability of communication

Exclusion Criteria:

• puncture site infection
• patients with coagulation disorders
• patients who refuse to participate or withdraw due to personal reasons
• allergy to local anesthetics.
• past surgery at the site of the block
• hip ankylosis
• drug abuse
• Body mass index ≥ 35 kg/m2
• peripheral vascular insufficiency
• use of alpha or beta blocker agents
• Nerve injury or neuropathy of the affected lower limb
• cardiovascular or respiratory decompansation

Randomization assignments will be kept in sealed envelopes until all preprocedural measurements will be completed