title: The effect of tourniquet use in total knee arthroplasty: grading the evidence through an updated meta-analysis of randomized, controlled trials.
abstract: OBJECTIVE
  Although tourniquets are widely used in total knee arthroplasty (TKA), the effectiveness and safety are still in controversy. We therefore conducted an updated meta-analysis to compare the outcomes of tourniquet-assisted to non-tourniquet-assisted TKA and provide recommendations for using tourniquet in TKA.
  
  
  METHODS
  A systematic search of studies published through March 2013 was conducted using MEDLINE, EMBASE, OVID, and ScienceDirect. Randomized, controlled trials that assessed the influence of the use of a tourniquet in TKA and provided data on safety and clinical effects were identified. Demographic characteristics, adverse events, and clinical outcomes were manually extracted from all of the selected studies. The evidence quality levels and recommendations were assessed using the GRADE system.
  
  
  RESULTS
  Fifteen studies encompassing 804 patients and comparing TKA with and without the use of a tourniquet met the inclusion criteria. Overall, the result of meta-analysis indicated that using a tourniquet could decrease the intraoperative blood loss but could increase the postoperative blood loss. However, there was no statistically significant difference in calculated blood loss and measured total blood loss between the tourniquet and non-tourniquet group. There was no statistically significant difference in operation time. Patients treated with a tourniquet might not have higher risks of thromboembolic complications, such as deep vein thrombosis and pulmonary thromboembolism. The overall GRADE system evidence quality was very low, which lowers our confidence in their recommendations.
  
  
  CONCLUSIONS
  As a safe application, the use of a tourniquet during TKA may be effective for reducing intraoperative blood loss, but not for reducing the postoperative blood loss and actual total blood loss. However, no uniform guideline can be made based on the current evidence because of the very low evidence quality and lower GRADE recommendation strength.
authors.affiliation: Department of Orthopaedics, The Third Hospital of Hebei Medical University, Hebei Medical University, Shijiazhuang, 050051, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Li
authors.forename: Lu
authors.initials: L
authors.lastname: Yin
authors.forename: Zhao-Yu
authors.initials: ZY
authors.lastname: Chen
authors.forename: Lian
authors.initials: L
authors.lastname: Zhu
authors.forename: Hai-Li
authors.initials: HL
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.forename: Guang
authors.initials: G
authors.lastname: Yang
authors.forename: Ying-Ze
authors.initials: YZ
authors.lastname: Zhang
mesh_terms: D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects / Q000379:methods*; D016063:Blood Loss, Surgical / Q000517:prevention & control; D001810:Blood Volume; D019317:Evidence-Based Medicine; D006801:Humans; D061646:Operative Time; D019106:Postoperative Hemorrhage / Q000209:etiology; D011655:Pulmonary Embolism / Q000209:etiology; D016032:Randomized Controlled Trials as Topic; D014111:Tourniquets / Q000009:adverse effects; D020246:Venous Thrombosis / Q000209:etiology