title: [Effect of preoperative cyclooxygenase-2 inhibitor for postoperative pain in patients after total knee arthroplasty: a meta-analysis].
abstract: OBJECTIVE
  To systematically evaluate the efficacy and safety of preoperative administration of cyclooxygenase-2 (COX-2) inhibitor on pain occurring with total knee arthroplasty (TKA).
  
  
  METHODS
  We electronically searched PubMed, Cochrane Library, EMBASE, CNKI, CBM, Wanfang data from inception to March 15, 2014 and manual searched journal of library collection to identify randomized controlled trials (RCTs) about preoperative administration of COX-2 inhibitor on pain occurring with TKA. The methodological quality of the included RCTs was assessed and the data were extracted according to the Cochrane Handbook 5.1.0. Meta-analysis was performed by using RevMan 5.2 software.
  
  
  RESULTS
  A total of 6 RCTs involving 228 patients were included. The results of meta-analyses showed that: (1) Efficacy: The visual analog scale (VAS) of post-operation at 12-hour (WMD = -0.60, 95% CI -0.83 to -0.37, P < 0.000 01) and 24-hour (WMD = -0.74, 95% CI -1.29 to - 0.19, P = 0.008) was decreased when COX-2 inhibitor was used before operation. And compared with control group, experimental group decreased the modified numerical pain rating scale (MNPRS) at 24-hour (WMD = -0.50, 95% CI -0.70 to -0.30, P < 0.000 01), 48-hour (WMD = -0.55,95% CI -0.65 to -0.45,P < 0.000 01) under quiescent conditions, and the same result at 24-hour (WMD = -0.82, 95% CI -1.26 to -0.38, P <0.000 01), 48-hour (WMD = -0.71, 95% CI -0.82 to -0.60, P < 0.000 01) under active conditions. The morphine consumption postoperatively were fewer in experimental group at the first day (WMD = - 1.35, 95% CI -1.92 to -0.79, P < 0.000 01) and the second day (WMD = -1.60, 95% CI -2.68 to -0.52, P = 0.004). (2) Safety: COX-2 inhibitor could lessen the incidence of postoperative pruritus (RR = 0.35, 95% CI 0.15 to 0.84, P = 0.02), but not statistically decrease of nausea and vomiting (RR = 0.83, 95% CI 0.54 to 1.28, P = 0.40) and exhaustion (RR = 0.63, 95% CI 0.05 to 7.67, P = 0.72).
  
  
  CONCLUSIONS
  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.
authors.forename: Zhong-wei
authors.initials: ZW
authors.lastname: Ji
authors.forename: Ni-rong
authors.initials: NR
authors.lastname: Bao
authors.forename: Jian-ning
authors.initials: JN
authors.lastname: Zhao
authors.forename: Jian-fa
authors.initials: JF
authors.lastname: Ni
mesh_terms: D019645:Arthroplasty, Replacement, Knee; D052246:Cyclooxygenase 2 Inhibitors / Q000627:therapeutic use*; D006801:Humans; D010149:Postoperative Pain / Q000188:drug therapy*; D011183:Postoperative Complications / Q000517:prevention & control; D011537:Pruritus / Q000517:prevention & control
chemical_list: D052246:Cyclooxygenase 2 Inhibitors