The investigators have implemented a new technique for performing the ACB. This block is performed using a 20G fenestrated needle. The needle is FDA approved for peripheral nerve block. It has an occluded tip with 8 side ports on alternating sides of the distal 2cm. Injection through the fenestrated needle produces effective distribution of local anesthetic to nerves of the adductor canal without immediate proximity to the femoral artery and vein. The ultrasound landmarks used to perform ACB with the fenestrated needle are readily visible even in patients with very large thigh circumference.