This study aims to describe and to evaluate the effectiveness (success rate) of a supine ultrasound (US) guided single-puncture sciatic, obturator and femoral neve block technique (SOFT block) in knee surgery.

Under aseptic technique, all the patients will receive US-guided femoral, obturator and sciatic nerve blocks using a single puncture point. All blocks will be performed by an expert anesthetist. The femoral nerve will be blocked lateral to the femoral artery. The obturator nerve will be blocked after it exits the obturator canal (deep to pectineus muscle). While the sciatic nerve will be blocked deep (posterior) to the inferior border of quadratus femoris muscle. The motor block of the femoral, obturator and sciatic nerves and sensory block of the lateral femoral cutaneous nerve (LFCN) will be assessed before shifting the patient to the operating room.

The performance time, patient discomfort, technique success rate, the associated successful LFCN block and any complication will be recorded by the assistant. All patients were assessed neurologically before discharge and during the physiotherapy visits for 3 weak after surgery.

Inclusion Criteria:

• Adult patients scheduled for arthroscopic knee ligament reconstruction

Exclusion Criteria:

• BMI > 30 kg.m-2,
• ASA physical state >II
• Allergy to the used local anesthetics
• Infection at the injection site
• age <18y