The efficacy of ketamine in total knee arthroplasty: a randomized controlled trial protocol.

Background: Appropriate pain management is essential to improve the postoperative recovery after total knee arthroplasty (TKA). There is a paucity of literature on ketamine for TKA procedures. The aim of this study was to evaluate the analgesic efficacy of ketamine in patients undergoing primary TKA. Methods: This study was designed as a prospective, double blind, single center, randomized controlled trial. The participants were randomly assigned to either the ketamine or placebo groups, using a set of random numbers for the allocation sequence. All patients underwent TKA without patella resurfacing under spinal anesthesia. Preoperative workup, surgical technique, and postoperative management were standardized for all the patients. The primary outcome of this noninferiority study is opioid consumption within the first 24hours following surgery, pain scores, distance ambulated, patient satisfaction, length of hospital stay, and complications. Results: The results of this study were expected to provide useful information on the effectiveness and safety of ketamine for immediate postoperative analgesia after TKA surgery.