Dynamic finite element knee simulation for evaluation of knee replacement mechanics

Area of Science:

• Biomechanics
• Computational modeling
• Orthopedic implant evaluation

Background:

• In vitro pre-clinical testing of total knee replacement (TKR) devices is crucial for evaluating new implant designs.
• Whole joint knee simulators offer controlled testing but are time and cost-prohibitive for extensive design variations.
• Experimentally-verified computational models offer an efficient alternative for analyzing multiple design parameters.

Purpose of the Study:

• To develop and validate a computational model of a dynamic, whole joint knee simulator.
• To enable efficient analysis of numerous total knee replacement design variations.
• To provide a platform for investigating clinical and research questions related to knee biomechanics.

Main Methods:

• Created specimen-specific finite element (FE) models of posterior-stabilized TKR from medical imaging and CAD data.
• Optimized soft-tissue properties using experimental laxity data from cadaveric specimens.
• Simulated dynamic deep knee bend and gait activities using a computational model of the Kansas knee simulator (KKS) with a PID controller.

Main Results:

• The computational model accurately predicted six degree-of-freedom patellofemoral (PF) and tibiofemoral (TF) kinematics and actuator loading.
• Model predictions showed good agreement with experimental data, with kinematic differences under 1.8 mm for translations and 2.2° for rotations.
• The validated FE simulator demonstrated its capability to replicate dynamic activities within the KKS.

Conclusions:

• The developed whole joint FE simulator provides an efficient and accurate method for pre-clinical evaluation of TKR designs.
• This computational approach significantly reduces the experimental burden for analyzing multiple implant variations and alignment conditions.
• The validated model can be applied to a broad spectrum of clinical and research inquiries in knee biomechanics and TKR development.