title: Mobile bearing or fixed bearing? A meta-analysis of outcomes comparing mobile bearing and fixed bearing bilateral total knee replacements.
abstract: BACKGROUND
  To compare outcomes between mobile-bearing (MB) and fixed-bearing (FB) in bilateral total knee replacements.
  
  
  METHODS
  The MEDLINE, EMBASE and Cochrane Library databases were searched. Randomized controlled trials of bilateral total knee arthroplasty with one of each design implanted were identified. Weighted mean differences (WMDs) and pooled risk ratios (RRs) were calculated using fixed- or random-effects models.
  
  
  RESULTS
  Twelve studies were identified with a total of 807 patients and 1614 knees. All RCTs were of high quality with a low risk of bias. No statistical difference was found between MB and FB at 2- to 5-year follow-up in terms of America Knee Society score (WMD: -1.29, 95% CI: -5.65 to 3.06), pain score (WMD: -3.26, 95% CI: -10.45 to 3.93), range of motion (WMD: -4.16, 95% CI: -9.97 to 1.66), reoperation (RR: 1.00, 95% CI: 0.28 to 3.60), and radiolucent lines (RR: 1.51, 95% CI: 0.70 to 3.24). The results were similar at 1-, 5- to 8-, or >8-year follow-up. Patient's satisfaction (RR: 0.85, 95% CI: 0.54 to 1.34), and complication (≤2-year, RR: 0.55, 95% CI: 0.29 to 1.04; >2-year, RR: 1.0, 95% CI=0.73 to 1.38) also showed no difference between two groups.
  
  
  CONCLUSIONS
  Based on this meta-analysis we are unable to detect the superiority of MB as compared to FB. More randomized trials with a larger sample size and longer follow-up are needed to evaluate these two kinds of prosthesis.
  
  
  METHODS
  Therapeutic Level II.
authors.affiliation: Department of Orthopedic Trauma and Hand Surgery, The First Affiliated Hospital of Guangxi Medical University, No. 6, Shuang Yong Road, Nanning 530021, Guangxi Province, China.
authors.forename: Zhan-dong
authors.initials: ZD
authors.lastname: Bo
authors.affiliation: Department of Orthopedic Trauma and Hand Surgery, The First Affiliated Hospital of Guangxi Medical University, No. 6, Shuang Yong Road, Nanning 530021, Guangxi Province, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Liao
authors.affiliation: Department of Orthopedic Trauma and Hand Surgery, The First Affiliated Hospital of Guangxi Medical University, No. 6, Shuang Yong Road, Nanning 530021, Guangxi Province, China. Electronic address: zhaojinmin@126.com.
authors.forename: Jin-min
authors.initials: JM
authors.lastname: Zhao
authors.affiliation: Department of Orthopedic Trauma and Hand Surgery, The First Affiliated Hospital of Guangxi Medical University, No. 6, Shuang Yong Road, Nanning 530021, Guangxi Province, China.
authors.forename: Qing-jun
authors.initials: QJ
authors.lastname: Wei
authors.affiliation: Department of Orthopedic Trauma and Hand Surgery, The First Affiliated Hospital of Guangxi Medical University, No. 6, Shuang Yong Road, Nanning 530021, Guangxi Province, China.
authors.forename: Xiao-fei
authors.initials: XF
authors.lastname: Ding
authors.affiliation: Department of Orthopedic Trauma and Hand Surgery, The First Affiliated Hospital of Guangxi Medical University, No. 6, Shuang Yong Road, Nanning 530021, Guangxi Province, China.
authors.forename: Biao
authors.initials: B
authors.lastname: Yang
mesh_terms: D019645:Arthroplasty, Replacement, Knee; D006801:Humans; D007720:Knee Prosthesis; D010147:Pain Measurement; D063868:Patient Outcome Assessment; D017060:Patient Satisfaction; D011183:Postoperative Complications; D011474:Prosthesis Design; D016032:Randomized Controlled Trials as Topic; D016059:Range of Motion, Articular; D012086:Reoperation
keywords: Bilateral; Fixed bearing; Meta-analysis; Mobile bearing; Total knee arthroplasty