title: Clinical and Biomechanical Evaluations of Staged Bilateral Total Knee Arthroplasty Patients with Two Different Implant Designs.
abstract: BACKGROUND
  Various implants of total knee arthroplasty (TKA) are used in clinical practice and each presents specific design characteristics. No implant managed this day to reproduce perfectly the biomechanics of the natural knee during gait.
  
  
  OBJECTIVE
  We therefore asked whether (1) differences in tridimensional (3D) kinematic data during gait could be observed in two different designs of TKA on the same patients, (2) if those gait kinematic data are comparable with those of asymptomatic knees and (3) if difference in clinical subjective scores can be observed between the two TKA designs on the same patient.
  
  
  METHODS
  We performed knee kinematic analysis on 15 patients (30 TKAs) with two different TKA implant designs (Nexgen, Zimmer and Triathlon, Stryker) on each knee and on 25 asymptomatic subjects (35 knees). Clinical evaluation included range of motion, weight bearing radiographs, questionnaire of joint perception, KOOS, WOMAC and SF-12.
  
  
  RESULTS
  Comparison between TKAs and asymptomatic knees revealed that asymptomatic knees had significantly less knee flexion at initial contact (p < 0.04) and more flexion for most of the swing phase (p between 0.004 and 0.04). Asymptomatic knees also had less varus at loading response, during stance phase and during most of the swing phase (p between 0.001 - 0.05). Transverse plane analysis showed a tendency for asymptomatic knees to be more in internal rotation during stance phase (p 0.02 - 0.04). Comparing both TKA designs, Nexgen(TM) implant had significantly more flexion at the end of swing phase (p = 0.04) compared to knees with the Triathlon(TM) implant. In frontal plane, from initial contact to maximum mid stance angle and between the mean mid stance angle and initial contact Nexgen(TM) TKA had significantly more adduction (varus, p =0.02 - 0.03). Clinical scores of both TKAs did not have significant difference.
  
  
  CONCLUSIONS
  TKA with the tested implants did not reproduce natural knee kinematics during gait. In our cohort of patients, TKA implant design translated in limited kinematics differences during gait and on clinical results.
authors.affiliation: Hôpital Maisonneuve-Rosemont, Université de Montréal, 5415 Boulevard de l'Assomption Montreal, H1T 2M4 Quebec, Canada.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Renaud
authors.affiliation: Laboratoire de recherche en Imagerie Orthopédique, École de Technologie Supérieure, Centre de Recherche du CHUM, Tour Viger 900, rue St-Denis, local R11.322 Montreal, H2X 0A9 Quebec, Canada.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Fuentes
authors.affiliation: Laboratoire de recherche en Imagerie Orthopédique, École de Technologie Supérieure, Centre de Recherche du CHUM, Tour Viger 900, rue St-Denis, local R11.322 Montreal, H2X 0A9 Quebec, Canada; École de Technologie Supérieure, 1100 Notre-Dame Ouest, Montreal, H3C 1K3 Quebec, Canada.
authors.forename: Nicola
authors.initials: N
authors.lastname: Hagemeister
authors.affiliation: Hôpital Maisonneuve-Rosemont, Université de Montréal, 5415 Boulevard de l'Assomption Montreal, H1T 2M4 Quebec, Canada.
authors.forename: Martin
authors.initials: M
authors.lastname: Lavigne
authors.affiliation: Hôpital Maisonneuve-Rosemont, Université de Montréal, 5415 Boulevard de l'Assomption Montreal, H1T 2M4 Quebec, Canada.
authors.forename: Pascal-André
authors.initials: PA
authors.lastname: Vendittoli
keywords: arthroplasty; design; function; gait; kinematic; knee replacement; total knee