**2. Search of literature**

Our review team completed the search of electronic databases, including the Cochrane Central Register of Controlled Trials (2010), PubMed Medline (1966 to May 2011), and Embase (1980 to May 2011). We used the following search terms and Boolean operators: (tourniquet) AND (knee OR arthroplasty OR joint replacement). We also searched the reference lists of the relevant articles for any further associated studies. The criteria for inclusion were (1) reports dealing with patients undergoing primary TKA and (2) studies about tourniquet use. After reviewing the titles and abstracts of the studies, we determined if the study was appropriate for retrieval. The retrieved literature was completely reviewed. A consensus about the content of this review article was reached throughout series of discussion.
