title: No differences in in vivo kinematics between six different types of knee prostheses.
abstract: OBJECTIVE
  The aim of this study was to compare a broad range of total knee prostheses with different design parameters to determine whether in vivo kinematics was consistently related to design. The hypothesis was that there are no clear recognizable differences in in vivo kinematics between different design parameters or prostheses.
  
  
  METHODS
  At two sites, data were collected by a single observer on 52 knees (49 subjects with rheumatoid arthritis or osteoarthritis). Six different total knee prostheses were used: multi-radius, single-radius, fixed-bearing, mobile-bearing, posterior-stabilized, cruciate retaining and cruciate sacrificing. Knee kinematics was recorded using fluoroscopy as the patients performed a step-up motion.
  
  
  RESULTS
  There was a significant effect of prosthetic design on all outcome parameters; however, post hoc tests showed that the NexGen group was responsible for 80% of the significant values. The range of knee flexion was much smaller in this group, resulting in smaller anterior-posterior translations and rotations.
  
  
  CONCLUSIONS
  Despite kinematics being generally consistent with the kinematics intended by their design, there were no clear recognizable differences in in vivo kinematics between different design parameters or prostheses. Hence, the differences in design parameters or prostheses are not distinct enough to have an effect on clinical outcome of patients.
  
  
  METHODS
  Therapeutic study, Level III.
authors.affiliation: Biomechanics and Imaging Group, Department of Orthopaedics, Leiden University Medical Center, PO Box 9600, J11-S, 2300 RC, Leiden, The Netherlands. N.Wolterbeek@lumc.nl
authors.forename: N
authors.initials: N
authors.lastname: Wolterbeek
authors.forename: R G H H
authors.initials: RG
authors.lastname: Nelissen
authors.forename: E R
authors.initials: ER
authors.lastname: Valstar
mesh_terms: D000368:Aged; D001172:Arthritis, Rheumatoid / Q000601:surgery; D001696:Biomechanical Phenomena; D005260:Female; D005471:Fluoroscopy; D006801:Humans; D007719:Knee Joint / Q000502:physiology; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery; D011474:Prosthesis Design; D016059:Range of Motion, Articular