Saphenous Nerve Block vs. Femoral Nerve Block for Total Knee Arthroplasty

One leg will receive the saphenous nerve block, at the level of the adductor canal (study technique). The block will be under ultrasound guidance. The local anesthetic will be 15 ml of 0.5% bupivacaine. All study patients, regardless of study arm will receive combined spinal epidural, with 3 ml of 0.5% bupivacaine as the spinal agent. Epidural local anesthetic, if needed, will consist of 2% lidocaine.

The other leg will receive the femoral nerve block (control technique). The block will be under ultrasound guidance. The local anesthetic will be 30 ml of 0.25% bupivacaine. All study patients, regardless of study arm will receive combined spinal epidural, with 3 ml of 0.5% bupivacaine as the spinal agent. Epidural local anesthetic, if needed, will consist of 2% lidocaine.