High Versus Low Adductor Canal Block

The investigators will be comparing the efficacy of two different techniques for performing an adductor canal block to the saphenous nerve as a part of the multimodal pain control regimen for total knee arthroplasty. The investigators will be comparing a "low adductor canal block" in which the surgeon administers local anesthetic to the distal aspect of the nerve from the operative site to a "high adductor canal block" in which the anesthesiologist administers the local anesthetic more proximally along the thigh using ultrasound guidance. The investigators will power the study for non-inferiority to compare the newer "low" block to the more commonly performed and more widely studied "high" block.