title: Functional performance of mobile versus fixed bearing total knee prostheses: a randomised controlled trial.
abstract: OBJECTIVE
  The primary goal of this study was to assess the difference in active flexion between patients with a mobile versus a fixed bearing, cruciate retaining, and total knee arthroplasty. The study was designed as a randomised controlled multi-centre trial.
  
  
  METHODS
  Participants were assigned to interventions by using block-stratified, random allocation. Outcome parameters were active flexion, passive flexion, and Knee Society Score (KSS). Outcome parameters were assessed preoperatively and at 3, 6, and 12 months postoperatively by an independent nurse.
  
  
  RESULTS
  Ninety-two patients from one centre were included, 46 in each group. Active flexion was comparable for the two groups, 99.9° for the mobile bearing group and 101° for the fixed bearing group with a baseline controlled difference of 1.0 (95% CI -3.9 to 5.8, n.s.). The Clinical KSS was comparable between the two bearing groups (Mobile 90.0 vs. fixed 92.4, n.s.). The functional KSS showed a difference that was attributable to the stair climbing subscore, which showed a difference in favour of the fixed bearing design between preoperative and 3 months (7.3 point difference; 95% CI 2.3-12.5; P = 0.005) as well as 12 months (4.8 point difference; 95% CI 0.1-9.6; P = 0.045).
  
  
  CONCLUSIONS
  There were no short-term differences in active flexion between fixed bearing and mobile bearing total knee arthroplasty.
  
  
  METHODS
  I.
authors.affiliation: Department of Neurosurgery, Leiden University Medical Center, Albinusdreef 2, PO Box 9600, 2300 RC, Leiden, The Netherlands. wch.jacobs@gmail.com
authors.forename: W C H
authors.initials: WC
authors.lastname: Jacobs
authors.forename: B
authors.initials: B
authors.lastname: Christen
authors.forename: A B
authors.initials: AB
authors.lastname: Wymenga
authors.forename: A
authors.initials: A
authors.lastname: Schuster
authors.forename: D B
authors.initials: DB
authors.lastname: van der Schaaf
authors.forename: A
authors.initials: A
authors.lastname: ten Ham
authors.forename: U
authors.initials: U
authors.lastname: Wehrli
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology* / Q000601:surgery; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000503:physiopathology / Q000601:surgery*; D011474:Prosthesis Design; D016059:Range of Motion, Articular; D020127:Recovery of Function; D016896:Treatment Outcome