Group one (G1): FNB technique
Placing the US probe on the proximal thigh perpendicular to its long axis, the femoral artery was located and followed towards the inguinal ligament. The femoral nerve was identified external to the artery. The injection point was located 1–2 cm distal to the inguinal ligament before the femoral artery bifurcation. Using an in-plane approach, the needle was advanced in a lateral-to-medial direction until the tip was located next to the femoral nerve.