Comparison between kinetic and kinetic-kinematic driven knee joint finite element models

Area of Science:

• Biomechanics
• Computational modeling
• Orthopedics

Background:

• Finite element models (FEM) of the knee joint are crucial for understanding joint mechanics.
• Complex FEMs provide detailed insights but are computationally intensive, limiting their use in large-scale studies.
• There is a need for simplified yet accurate knee joint models for analyzing large patient cohorts.

Purpose of the Study:

• To compare the accuracy of kinetic-kinematic driven (simpler) versus kinetic driven (complex) finite element models of the knee joint during the stance phase of gait.
• To evaluate the feasibility of using simplified knee models for large cohort studies without compromising diagnostic results, particularly concerning cartilage stress and strain.

Main Methods:

• Developed and compared two finite element models of the knee joint: a complex model including patella and tendons, driven by kinetic data (forces and moments), and a simpler model driven by kinetic-kinematic data (forces and angles).
• Analyzed the stance phase of gait for both models.
• Quantified differences in joint rotations, translations, joint reaction forces, and cartilage stresses and strains between the two models.

Main Results:

• The greatest discrepancies between the complex and simpler models were observed in internal-external rotation and axial joint reaction force.
• All other rotations, translations, and joint reaction forces showed high similarity between the models.
• Cartilage stresses and strains in the lateral compartment were similar; minor differences were noted in the medial compartment early in the stance phase.

Conclusions:

• Kinetic-kinematic driven knee joint finite element models with simpler geometry are feasible for large cohort studies.
• These simplified models can be effectively used for analyzing cartilage responses and failures related to potential overloads, especially in large-scale patient analyses.
• The use of simplified models offers a computationally efficient alternative without significant loss of accuracy for specific biomechanical assessments.