title: The description of the human knee as four-bar linkage.
abstract: OBJECTIVE
  We investigate the dependence of the kinematics of the human knee on its anatomy. The idea of describing the kinematics of the knee in the sagittal plane using four-bar linkage is almost as old as kinematics as an independent discipline. We start with a comparison of known four-bar linkage constructions. We then focus on the model by H. Nägerl which is applicable under form closure.
  
  
  METHODS
  We use geometry and analysis as the mathematical methods. The relevant geometrical parameters of the knee will be determined on the basis of the dimensions of the four-bar linkage. This leads to a system of nonlinear equations.
  
  
  RESULTS
  The four-bar linkage will be calculated from the limits of the constructively accessible parameters by means of a quadratic approximation.
  
  
  CONCLUSIONS
  By adapting these requirements to the dimensions of the human knee, it will be possible to obtain valuable indications for the design of an endoprosthesis which imitates the kinematics of the natural knee.
authors.affiliation: University Medical Center, Department of Medical Informatics, Georg-August-University, Göttingen, Germany.|Joint Biomechanical Research Group, Department of Orthodontics, Georg-August-University, Göttingen, Germany.
authors.forename: Henning
authors.initials: H
authors.lastname: Dathe
authors.affiliation: Joint Biomechanical Research Group, Department of Orthodontics, Georg-August-University, Göttingen, Germany.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Gezzi
authors.affiliation: Lima Corporate, Udine Italy.
authors.forename: Christoph
authors.initials: C
authors.lastname: Fiedler
authors.affiliation: Joint Biomechanical Research Group, Department of Orthodontics, Georg-August-University, Göttingen, Germany.
authors.forename: Dietmar
authors.initials: D
authors.lastname: Kubein-Meesenburg
authors.affiliation: Joint Biomechanical Research Group, Department of Orthodontics, Georg-August-University, Göttingen, Germany.
authors.forename: Hans
authors.initials: H
authors.lastname: Nägerl
mesh_terms: D003198:Computer Simulation; D005269:Femur / Q000033:anatomy & histology / Q000502:physiology; D006801:Humans; D007717:Knee / Q000033:anatomy & histology* / Q000502:physiology*; D007719:Knee Joint / Q000033:anatomy & histology* / Q000502:physiology*; D008954:Models, Biological; D016059:Range of Motion, Articular / Q000502:physiology*; D013977:Tibia / Q000033:anatomy & histology / Q000502:physiology