Integration of freeze-drying and Lugol-enhanced µCT imaging in virtual meniscus modelling for 3D printing and FE analysis

The knee menisci maintain stability and function of a healthy knee joint. Therefore, degenerative, or traumatic meniscus injuries may require meniscal implants to restore function. The aim of this study was to create a 3D-printable meniscus implant that emphasizes the representation of circumferential collagen fibres for biomechanical function. A novel Lugol-staining and freeze-drying technique was developed to prepare six human menisci for analysis of circumferential fibre volume proportion using μCT scans. Average volumes of 46.09% and 50.23% were observed in the medial and lateral meniscus, respectively. The resulting STL file, generated with UltiMaker Cura, had a circumferential infill structure occupying 48% of the total volume. A Python script was developed to extract coordinates from the G-code, facilitating the conversion of complex STL geometries into detailed volumetric finite element models (FEMs). These FEMs allow adjustment of volume proportions and outer layer thicknesses for finite element analysis (FEA), enabling virtual simulations to assess biomechanical properties and modify designs prior to implant manufacture. This methodology represents a promising avenue for advances in orthopaedic tissue engineering employing 3D-printing approaches.