Timing of tourniquet release in total knee arthroplasty

BACKGROUND For total knee arthroplasty (TKA), the tourniquet is routinely employed for better visualization, less blood loss, and easier cementation. However, the time to release tourniquet remains controversial. Therefore, we performed current meta-analysis to assess whether releasing tourniquet before wound closure is more effective in reducing blood loss than releasing tourniquet after wound closure in TKA without an increased risk of complications. METHODS To conduct this meta-analysis, we searched Medline, Embase, Web of science, and the Cochrane library up to November 2016, for randomized controlled trials comparing tourniquet releasing before and after wound closure in TKA. A meta-analysis was performed following the guidelines of the Cochrane Reviewer's Handbook and the PRISMA statement. Methodological quality of the trials was assessed using the Cochrane risk assessment scale. The data of the included studies were analyzed using Stata 12.0. RESULTS Sixteen trials involving 1010 patients were identified in current meta-analysis. Our meta-analysis demonstrated that there were no significant differences in the 2 groups in terms of calculated blood loss (weighted mean difference [WMD] = 160.65, 95% confidence interval [CI]: -0.2 to 321.49, P = .05), postoperative blood loss (WMD = -45.41, 95% CI: -120.11 to 29.29, P = .233),postoperative hemoglobin decline (WMD = 0.16, 95% CI: -2.5 to 2.82, P = .905), transfusion volume (WMD = 79.19, 95% CI: -5.05 to 163.44, P = .065),transfusion rates (relative risk [RR] = 1.19, 95% CI: 0.95-1.50, P = .134), major complications (RR = 0.51, 95% CI: 0.15-1.73, P = .278), and deep vein thrombosis (RR = 0.44, 95% CI: 0.14-1.37, P = .157).Compared with the group of releasing tourniquet after wound closure, the group of releasing tourniquet before wound closure had a higher volume of total blood loss (WMD = 130.96, 95% CI: 58.83-203.09, P = .000) and a longer operation time (WMD = 6.56, 95% CI: 3.12-10.01, P = .000). However, releasing tourniquet before wound closure could reduce minor complications (RR = 0.53, 95% CI: 0.34-0.82, P = .004). CONCLUSIONS On the basis of current meta-analysis, the method of releasing tourniquet before wound closure could increase total blood loss and operation time; nevertheless, the risk of complications decreased. Thus, if patients are in severe anemia condition, the tourniquet perhaps should be released after wound closure to decrease blood loss. In contrary, releasing tourniquet before wound closure to decrease the risk of complications would be a better choice.