Computational modeling of articular cartilage: Mechanical experiments, sensitivity analyses, parameter...

Area of Science:

• Biomechanics
• Biomaterials Science
• Computational Biology

Background:

• Articular cartilage is a complex, multiphase material vital for joint function.
• Osteoarthritis and other diseases significantly impact cartilage mechanical behavior.
• Accurate finite element simulations are crucial for understanding cartilage mechanics.

Purpose of the Study:

• To improve the fidelity of finite element simulations for articular cartilage.
• To refine a well-established biphasic constitutive model using integrated experimental data and analyses.
• To provide a robust computational tool for investigating cartilage mechanics.

Main Methods:

• Integrated mechanical experiments (uniaxial extension, confined compression, biaxial extension).
• Sensitivity analyses (Morris method) to identify dominant material parameters.
• Parameter identification and model validation using experimental data and digital image correlation.

Main Results:

• Fiber stiffness was dominant in uniaxial extension; permeability and matrix stiffness were significant in confined compression.
• Parameter fitting achieved excellent matches with experimental data (R²≥0.989 for uniaxial, R²>0.998 for confined compression).
• Independent validation against biaxial extension showed simulated stress-strain curves within the experimental range.

Conclusions:

• The validated biphasic model accurately predicts articular cartilage mechanical behavior under various loading conditions.
• Results highlight the importance of fiber reinforcement in tension and fluid pressurization in compression.
• The study provides a valuable tool for research into cartilage degeneration and treatment development.