title: Development and validation of a weight-bearing finite element model for total knee replacement.
abstract: Total knee arthroplasty (TKA) is a successful procedure for osteoarthritis. However, some patients (19%) do have pain after surgery. A finite element model was developed based on boundary conditions of a knee rig. A 3D-model of an anatomical full leg was generated from magnetic resonance image data and a total knee prosthesis was implanted without patella resurfacing. In the finite element model, a restarting procedure was programmed in order to hold the ground reaction force constant with an adapted quadriceps muscle force during a squat from 20° to 105° of flexion. Knee rig experimental data were used to validate the numerical model in the patellofemoral and femorotibial joint. Furthermore, sensitivity analyses of Young's modulus of the patella cartilage, posterior cruciate ligament (PCL) stiffness, and patella tendon origin were performed. Pearson's correlations for retropatellar contact area, pressure, patella flexion, and femorotibial ap-movement were near to 1. Lowest root mean square error for retropatellar pressure, patella flexion, and femorotibial ap-movement were found for the baseline model setup with Young's modulus of 5 MPa for patella cartilage, a downscaled PCL stiffness of 25% compared to the literature given value and an anatomical origin of the patella tendon. The results of the conducted finite element model are comparable with the experimental results. Therefore, the finite element model developed in this study can be used for further clinical investigations and will help to better understand the clinical aspects after TKA with an unresurfaced patella.
authors.affiliation: a Department of Orthopedic Surgery, Physical Medicine and Rehabilitation , University Hospital of Munich (LMU) , Munich , Germany.
authors.forename: M
authors.initials: M
authors.lastname: Woiczinski
authors.affiliation: a Department of Orthopedic Surgery, Physical Medicine and Rehabilitation , University Hospital of Munich (LMU) , Munich , Germany.
authors.forename: A
authors.initials: A
authors.lastname: Steinbrück
authors.affiliation: a Department of Orthopedic Surgery, Physical Medicine and Rehabilitation , University Hospital of Munich (LMU) , Munich , Germany.
authors.forename: P
authors.initials: P
authors.lastname: Weber
authors.affiliation: a Department of Orthopedic Surgery, Physical Medicine and Rehabilitation , University Hospital of Munich (LMU) , Munich , Germany.
authors.forename: P E
authors.initials: PE
authors.lastname: Müller
authors.affiliation: a Department of Orthopedic Surgery, Physical Medicine and Rehabilitation , University Hospital of Munich (LMU) , Munich , Germany.
authors.forename: V
authors.initials: V
authors.lastname: Jansson
authors.affiliation: a Department of Orthopedic Surgery, Physical Medicine and Rehabilitation , University Hospital of Munich (LMU) , Munich , Germany.
authors.forename: Ch
authors.initials: Ch
authors.lastname: Schröder
mesh_terms: D000328:Adult; D019645:Arthroplasty, Replacement, Knee; D001696:Biomechanical Phenomena; D003198:Computer Simulation; D055119:Elastic Modulus; D020342:Finite Element Analysis; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D007720:Knee Prosthesis; D008954:Models, Biological; D010329:Patella / Q000502:physiology; D016119:Posterior Cruciate Ligament / Q000502:physiology; D016059:Range of Motion, Articular / Q000502:physiology; D015203:Reproducibility of Results; D016474:Weight-Bearing / Q000502:physiology
keywords: Finite element method; controlled numerical model; experimental validation; knee rig; total knee arthroplasty