Work

Finite element-guided indirect 3D printing of gradient PVA hydrogel meniscus constructs: a proof-of-concept study

Year: 2026

Type: article

Abstract: Finite element analysis (FEA) can translate tissue-level mechanical information into fabrication-ready designs. However, its use for spatially graded hydrogel meniscus constructs remains limited, and simulation-derived differences require cautious interpretation when the fabricated material does not reproduce the modeled tissue properties. One porcine knee was reconstructed from computed tomography and magnetic resonance imaging to build a whole-knee meniscus model. The paired medial and lateral menisci from the same knee were divided into 12 regions, and three technical compressive measurements per region were used to assign regional moduli to matched finite element zones. Homogeneous and heterogeneous meniscus models were compared under identical geometry, boundary conditions, and a 1000 N axial load at 0° flexion. The specimen-specific modulus ranking (1.83–118.57 MPa) was simplified into low-, intermediate-, and high-modulus zones and fabricated using 10%, 15%, and 20% (w/v) polyvinyl alcohol hydrogel (PVA-H) formulations in 3D-printed molds. This mapping preserved rank order rather than absolute modulus equivalence. Compressive modulus, morphology, rheology, and preliminary extract-based cytocompatibility were assessed. In the FEA screening model, the heterogeneous assignment yielded a 10.3% lower modeled peak von Mises stress than the homogeneous average-modulus model (2.24 ± 0.02 MPa vs. 2.47 ± 0.03 MPa), and modeled zone-wise stress differences ranged from − 16.0% to + 30.1%. Mean equivalent strain differed minimally (0.071 ± 0.032 vs. 0.073 ± 0.033). The fabricated constructs reproduced the gross meniscal shape and showed continuous inter-zone interfaces. The measured compressive moduli of 10%, 15%, and 20% PVA-H were 0.42 ± 0.05, 0.89 ± 0.07, and 1.58 ± 0.11 MPa, respectively ( n = 5 per group); these values were substantially below the 1.83–118.57 MPa specimen-specific moduli used in the FEA. At 628.3 rad/s, descriptive frequency-sweep testing showed shear stresses of 4441 Pa for 20% PVA-H and 4239 Pa for native porcine meniscus. MC3T3-E1 extract testing showed no detectable cytotoxicity over 48 h in this preliminary assay. This proof-of-concept study presents a practical design-to-mold route for a discrete-gradient PVA-H meniscus prototype. Because the FEA used specimen-specific tissue moduli that were substantially higher than the fabricated PVA-H moduli, its predicted stress differences should not be transferred directly to the printed construct or interpreted as experimental proof of functional superiority. Future studies should incorporate anisotropic or fiber-reinforced constitutive models, whole-construct mechanical validation, fatigue and tribological testing, meniscus-relevant cells, and in vivo assessment. Not applicable.

Source: Journal of Orthopaedic Surgery and Research

DOI: 10.1186/s13018-026-07147-x