title: Postoperative leg position following total knee arthroplasty influences blood loss and range of motion: a meta-analysis of randomized controlled trials.
abstract: OBJECTIVE
  Postoperative leg position has been reported as an efficient and convenient technique to minimize blood loss and improve early recovery following total knee arthroplasty (TKA); however, no single study was large enough to definitively determine optimal leg position. Therefore, we performed a meta-analysis pooling the results from randomized controlled trials (RCTs) to evaluate the effect of postoperative leg position on blood loss and range of motion (ROM) in TKA.
  
  
  METHODS
  Potential academic articles were identified from the Cochrane Library, Medline (1966-October 2015), PubMed (1966-October 2015), Embase (1980-October 2015), ScienceDirect (1985-October 2015) and other databases. Gray studies were identified from the references of included literature reports. The pooling of data was analyzed by RevMan 5.1.
  
  
  RESULTS
  Ten RCTs were included in the meta-analysis. There were significant differences in the total blood loss (mean difference [MD] = -130.66, 95% CI: -198.74 to -62.57, P = 0.0002), hidden blood loss (MD = -73.27, 95% CI: -117.57 to -28.96, P = 0.001), blood transfusion requirement (risk difference [RD] = -0.10, 95% CI: -0.19 to -0.22, P = 0.02), postoperative hemoglobin level (MD = 0.73, 95% CI: 0.42 to 1.04, P < 0.00001) and range of motion (MD = 3.79, 95% CI: 1.43 to 6.14, P = 0.002) between the flexion group and extension group. No significant differences were found regarding length of hospital stay, deep vein thrombosis (DVT) and wound infection between the two groups.
  
  
  CONCLUSIONS
  This meta-analysis indicated that the postoperative flexion position of the leg in TKA was effective and safe, significantly decreasing total blood loss, hidden blood loss and blood transfusion requirement. In addition, the postoperative range of motion is significantly improved by the flexion position of the leg.
authors.affiliation: a Tianjin Hospital , Tianjin , China ;
authors.forename: Xin
authors.initials: X
authors.lastname: Fu
authors.affiliation: a Tianjin Hospital , Tianjin , China ;
authors.forename: Peng
authors.initials: P
authors.lastname: Tian
authors.affiliation: b General Hospital of Tianjin Medical University , Tianjin , China.
authors.forename: Zhi-jun
authors.initials: ZJ
authors.lastname: Li
authors.affiliation: a Tianjin Hospital , Tianjin , China ;
authors.forename: Xiao-lei
authors.initials: XL
authors.lastname: Sun
authors.affiliation: a Tianjin Hospital , Tianjin , China ;
authors.forename: Xin-long
authors.initials: XL
authors.lastname: Ma
mesh_terms: D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects* / Q000379:methods*; D001803:Blood Transfusion; D006454:Hemoglobins / Q000032:analysis; D006470:Hemorrhage / Q000517:prevention & control*; D006801:Humans; D007866:Leg; D007902:Length of Stay; D056888:Patient Positioning; D011183:Postoperative Complications; D011184:Postoperative Period; D016032:Randomized Controlled Trials as Topic; D016059:Range of Motion, Articular; D020246:Venous Thrombosis / Q000150:complications
chemical_list: D006454:Hemoglobins
keywords: Arthroplasty; Blood loss; Knee position; Meta-analysis; Range of motion