title: Does mobile-bearing knee arthroplasty motion change with activity?
abstract: BACKGROUND
  The purpose of this study was to evaluate the effect of mobile-bearing implant design and activity on knee arthroplasty kinematics during three activities of daily living.
  
  
  METHODS
  In vivo kinematics were analyzed using 3D model registration from fluoroscopic images of non-weightbearing knee flexion-extension, weight-bearing squatting and stair activities in 20 knees in 10 patients with bilateral total knee arthroplasty. Each patient had one rotating-platform and one meniscal-bearing variant of the same prosthesis design.
  
  
  RESULTS
  Anteroposterior translations in meniscal-bearing knees were larger than those in rotating-platform knees for the different dynamic conditions. Meniscal-bearing knees showed more posterior femoral locations with activities that increased demand on the quadriceps. Condylar translations changed little in rotating-platform knees with different activities.
  
  
  CONCLUSIONS
  Activity dynamics can have a significant influence on knee kinematics, and have a greater effect on the kinematics of unconstrained meniscal-bearing prostheses than rotating-platform knee prostheses.
  
  
  METHODS
  Level II.
authors.affiliation: Department of Orthopaedics, Takagi Hospital Oume Knee Surgery Center, Tokyo, Japan; Department of Mechanical & Aerospace Engineering, University of Florida, Gainesville, FL, USA. Electronic address: ymikashima2007@yahoo.co.jp.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Mikashima
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Ishii
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Takeda
authors.forename: Hideo
authors.initials: H
authors.lastname: Noguchi
authors.forename: Shigeki
authors.initials: S
authors.lastname: Momohara
authors.forename: Scott A
authors.initials: SA
authors.lastname: Banks
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D001696:Biomechanical Phenomena; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D011446:Prospective Studies; D011474:Prosthesis Design; D016059:Range of Motion, Articular / Q000502:physiology*; D012399:Rotation; D016474:Weight-Bearing / Q000502:physiology
keywords: Activity; Kinematics; Meniscal-bearing; Mobile-bearing knee arthroplasty; Rotating-platform