Patients undergoing total hip and knee arthroplasty experience substantial and sustained postoperative pain. Inadequate analgesia may impede physical therapy and rehabilitative efforts and delay hospital dismissal. Traditionally, postoperative analgesia after total joint replacement was provided by either intravenous patient-controlled analgesia or epidural analgesia. Each, however, had disadvantages as well as advantages. Peripheral nerve blockade of the lumbosacral plexus has emerged as an alternative analgesic approach. In several studies, unilateral peripheral block provided a quality of analgesia and functional outcomes similar to those of continuous epidural analgesia and superior to those of systemic analgesia, but with fewer side effects because of their opioid-sparing properties. Peripheral nerve block techniques may be the optimal analgesic method following total joint arthroplasty.