The Influence of Anesthetic Technique on Post-operative Pain Scores and Range of Motion in Primary Total Hip Arthroplasty

To compare analgesia and orthopedic rehabilitation milestones in patients receiving either spinal anesthesia (local anesthetic plus opioid) or general endotracheal anesthesia with lumbar plexus block.

: Total hip arthroplasty (THA) is a common surgery worldwide. Despite the prevalence of this procedure, there is no "gold standard" anesthetic. Several different techniques are utilized. The two most common anesthesia modalities are: 1) spinal anesthesia 2) general anesthesia (with or without a peripheral nerve block). The choice of anesthetic technique is often based on the training and experience of the anesthesia provider, as well as the culture of the institution. Both spinal anesthesia (consisting of local anesthetic and opioid) and general anesthesia (combined with lumbar plexus nerve block) can provide adequate intra-operative anesthesia as well as prolonged post-operative analgesia. The goal of this study is to determine if the choice of one of these two anesthetic techniques influences postoperative pain scores and orthopedic rehabilitation markers in patients undergoing primary THA.

Several studies have compared spinal versus general anesthesia in terms of post-operative pain relief, nausea and vomiting, blood loss, and deep venous thrombosis. Most of these studies did not utilize a lumbar plexus nerve block for postoperative analgesia in the general anesthesia subjects. The investigators are not aware of any randomized, controlled studies examining differences in orthopedic outcomes when THA is performed under spinal anesthesia or general anesthesia with lumbar plexus nerve block. These two anesthetic techniques result in different degrees of intraoperative muscle relaxation which may affect post-operative range of motion. Analgesic differences between the two techniques may also affect range of motion and post-operative ambulation.

The investigators propose to compare post-operative pain scores as a primary outcome in patients receiving either spinal anesthesia (bupivicaine with morphine) or general anesthesia with lumbar plexus block for THA. Orthopedic outcomes, including distance of first ambulation, physical therapy range of motion, and limb length discrepancies will be measured as secondary outcomes. Continuous pulse oximetry and capnograpahy data will be recorded for 24 hours postoperatively on all patients. The incidence of urinary tract infections and post-operative nausea and vomiting between groups will be additional measured outcomes.