Effects of postoperative administration of celecoxib on pain management in patients after total knee arthroplasty: study protocol for an open-label randomized controlled trial

BACKGROUND Multimodal analgesia is achieved by combining different analgesics and different methods of analgesic administration, synergistically providing superior pain relief when compared with conventional analgesia. Multimodal analgesia can also result in reductions in the side effects and complications of analgesia, thereby improving patient safety. Preventive analgesia, treatment before initiation of the surgical procedure, has a potential to be more effective in reducing pain sensitization than treatment initiated after surgery. Multimodal analgesia that includes prophylactic administration of selective cyclooxygenase-2 (COX-2) inhibitors can improve postoperative pain and reduce opioid analgesic consumption after total knee arthroplasty (TKA). However COX-2 inhibitors are not approved for use as preventive analgesia in Japan. Thus, assessing the effectiveness of COX-2 inhibitors during the early postoperative period is important to establish clinical practice guidelines in Japan. This study was designed to examine the effects of celecoxib administration immediately after surgery, in addition to multimodal analgesia, on postoperative pain management after TKA. METHODS/DESIGN This randomized, prospective, open-label controlled study will include 120 patients undergoing unilateral TKA. All patients will routinely receive single injections of femoral and sciatic nerve blocks, along with postoperative patient-controlled analgesia (PCA) with fentanyl. Patients will be randomly assigned to receive or not receive immediate postoperative administration of celecoxib. The primary outcome is a visual analog scale (VAS) pain score the second day after surgery. Secondary outcomes include opioid consumption, VAS pain score for 7 days after surgery, range of knee motion, evaluation of sleep quality, overall evaluations by patients and physicians, rates of postoperative nausea and vomiting, and consumption of rescue analgesics. DISCUSSION The objective of this study is to evaluate the effects of celecoxib administration immediately after surgery on pain after TKA surgery. A randomized controlled trial design will address the hypothesis that administration of oral celecoxib immediately after surgery, along with multimodal analgesia that includes peripheral nerve block and PCA, could reduce VAS pain score after TKA surgery. TRIAL REGISTRATION UMIN-CTR 000014624 (23 July 2014).