[Effect of preoperative cyclooxygenase-2 inhibitor for postoperative pain in patients after total knee arthroplasty: a meta-analysis].

The current evidence indicated that preoperative administration of COX-2inhibitor can effectively improve the effect of postoperative analgesia, reduce the consumption of morphine and lessen the incidence of pruritus. Due to the limited quantity of the included studies and the evidence with limited strength,further high-quality RCTs are needed to verify the aforementioned conclusion.