title: Comparison of High-Flexion and Conventional Implants in Total Knee Arthroplasty: A Meta-Analysis.
abstract: BACKGROUND
  The purpose of this study was to evaluate whether high-flexion prostheses are superior to conventional prostheses after total knee arthroplasty (TKA).
  
  
  METHODS
  We searched the PubMed and Embase databases for randomized trials and cohort studies comparing high-flexion with conventional knee implants. The heterogeneity across studies was examined by I2 and Cochran's Q-tests. Then the overall weighted mean differences of range of motion (ROM) and knee functional scores were evaluated.
  
  
  RESULTS
  A total of 16 trials involving 2643 knees met our inclusion criteria. The results revealed that high-flexion implants were superior to conventional implants in the improvement of range of motion (weighted mean difference, 2.92; 95% CI, 1.63-4.22; p<0.0001). The clear advantage of high-flex PS (posterior stabilized) as well as high-flex CR (cruciate retaining) implants was found in ROM when compared to PS implants (2.73; 95% CI, 1.27-4.20; p=0.0003) and CR implants (3.24; 95% CI, 0.28-6.20; p=0.003), respectively. However, there was no difference in Knee Society Scores (0.42; 95% CI, -0.60-1.43; p=0.42), Knee Society function (0.37; 95% CI, -1.48-2.22; p=0.70) and Hospital for Special Surgery scores (0.26; 95% CI, -0.47-1.00; p=0.48) between high-flexion and conventional groups.
  
  
  CONCLUSIONS
  The current meta-analysis revealed that high-flexion implants were superior to conventional implants in the improvement of ROM but not in functional outcome scores.
authors.affiliation: Department of Orthopaedics, Chinese PLA General Hospital, Beijing, China (mainland).
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Orthopaedics, Chinese PLA General Hospital, Beijing, China (mainland).
authors.forename: Min
authors.initials: M
authors.lastname: Wei
authors.affiliation: Department of Orthopaedics, Chinese PLA General Hospital, Beijing, China (mainland).
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Department of Orthopaedics, Chinese PLA General Hospital, Beijing, China (mainland).
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Orthopaedics, Chinese PLA General Hospital, Beijing, China (mainland).
authors.forename: Yaofei
authors.initials: Y
authors.lastname: Cui
mesh_terms: D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D007720:Knee Prosthesis / Q000706:statistics & numerical data*; D015233:Models, Statistical; D039781:PubMed; D016032:Randomized Controlled Trials as Topic