The nerve stimulator guided technique of continuous lumbar plexus block (LPB) is the accepted standard of care at University of Pittsburgh Medical Center (UPMC) for the management of postoperative analgesia after Total Hip Arthroplasty. Over 900 continuous lumbar plexus blocks were performed at UPMC Presbyterian Shadyside hospital within the last year alone. Continuous thoracic paravertebral block (TPVB) is also commonly performed at UPMC Presbyterian Shadyside . Over 2000 are performed annually for a wide variety of surgical procedures. Recently authors have suggested that a lumbar paravertebral block (LPVB) may represent an alternative approach to the lumbar plexus. Indeed the L2 paravertebral approach of the lumbar plexus has been described to provide adequate postoperative analgesia following hip arthroscopic surgery. However, to date, there is no prospective direct comparison between L2 Lumbar plexus approach and the posterior approach for postoperative analgesia after Total Hip Arthroplasty.