Adductor Canal Block (ACB) Before and After Primary Total Knee Arthroplasty (TKA)

Total knee arthroplasty (TKA) is associated with severe postoperative pain. Multimodal analgesia, including peripheral nerve block, is recommended for post-operative pain relief 1. Perineural analgesia offers the advantage of extended pain relief up to 24 hours after surgery2. This is a prospective, randomized control trial designed to compare the analgesic efficacy of the adductor canal block (ACB) performed immediately before or immediately after primary total knee arthroplasty (TKA). The primary objective of this study is to measure pain score associated with knee motion following TKA among patients receiving ACB as part of their analgesic regimen for TKA. Secondary end points include assessment of postoperative ambulation, range of motion, pain at rest, opioid consumption, and patient satisfaction between the two analgesic approaches. The investigators hypothesize that ACB before the surgery will reduce a patient's postoperative pain and improve patient satisfaction. All consecutive patients undergoing primary TKA will be recruited for enrollment in the study. Patients will be for randomized preoperatively to receive either preemptive ABC (PreACB) or postoperative ABC (PostACB). Patients randomized to the PreACB group will receive the block prior to incision. Patients randomized to the PostACB group will receive the block at the end of the surgery. Both techniques are in accordance to the standard of care at our institute. All patients will have the ACB done by a regional anesthesiologist in the regional anesthesia unit, or in the operating room. Patient medical history will be obtained and blocks will be placed per usual protocol. Operative and anesthetic details, including medications given, will be recorded. Pain scores and pain medications given in the PACU will be recorded. Supplementary analgesics will be provided per institutional PACU protocol. Study data will be recorded for up to 72 hours or until patient discharge. A follow-up will occur in 4- 6 we