Adductor Canal Block for Medial Compartment Knee Arthroplasty

This study will evaluate the affects of a single injection ultrasound-guided adductor canal block for patients undergoing robotic-assisted (MAKOplasty) medial UKA (unicompartmental knee arthroplasty). Specifically, this study will compare the adequacy of postoperative analgesia provided by the adductor canal block with that provided by single injection lumbar plexus blockade. The working hypothesis is that the analgesia provided by the adductor canal block will be equivalent to the analgesia provided by the lumbar plexus block. The primary outcome will be a comparison of verbal numerical pain scores at rest and with movement over the first 24 hours following nerve blockade.