FEA-Guided 3D Printing of Gradient-Modulus Polyvinyl Alcohol-Based Hydrogel Meniscus with Biomechanically Optimized Heterogeneity

Purpose: To develop a finite element analysis (FEA)-guided 3D printing strategy for fabricating polyvinyl alcohol-based hydrogel (PVA-H) meniscus models with anatomically accurate gradient mechanical properties. Methods: Porcine knee joint CT/MRI DICOM data were were reconstructed into three-dimensional (3D) model (Mimics 21.0) and processed for FEA (Geomagic Studio 2014, Hypermesh 14.0, MSC Nastran 2019). Region-specific elastic moduli were assigned based on biomechanical testing of six zones of porcine meniscus (Instron 5967). PVA-H (10-20% w/v) was synthesized via freeze-thaw cycling (-20°C, 8h cycles) and characterized using SEM, rheometry (AR2000EX), FTIR, and UV-Vis spectroscopy. Two mold-based 3D printing approaches were employed for fabrication the PVA-H heterogeneous meniscus model. Biocompatibility was assessed via CCK-8 assay and live/dead staining. Results: Compared to homogeneous models, the FEA-optimized heterogeneous model showed 9.3% reduction in peak stress (2.27 vs. 2.48 MPa), Physiological stress redistribution (13.9~32.1% increase in anterior horn/lateral body; 9.3~16.0% decrease in posterior horn), and superior stress transition smoothness. 3D-printed PVA-H constructs showed seamless inter-zone integration and anatomical fidelity. The 20% PVA-H exhibited native-like viscoelastic properties: comparable shear stress at 628.3 rad/s (4441 vs 4239 Pa), and similar viscosity profiles at >450 rad/s. The fabricated PVA-H meniscus model had excellent biocompatibility and no cell growth inhibition. Conclusion: This FEA-guided 3D printing approach successfully created biomechanically optimized, gradient-modulus PVA-H meniscus models that outperform homogeneous designs, representing a significant advancement toward functional meniscus substitutes.