Every year, 3DP provides more alternatives and solutions in the medical field. Applications such as custom-made prosthetics and implants, platforms for pharmaceutical research, and PSAMs are the immediate emerging trends. Certainly, 3DP advancement is the convergence of multiple factors including improvements in medical software, 3D printer evolution, availability of new printing materials, improved industry support, and increasing commitment from medical societies and regulators. The overarching theme of this study is centered on exploring possible PSAMs and 3DP applications for improving surgical outcomes in orthopedics, particularly in ACL-R as well as providing functional models for TKA.
3-Matic, Rhinoceros, and SolidWorks were used to create three 3D computer-generated PSAMs: (1) Knee Joint model, wherein collagen fibers matrix structure is mimicked, (2) ACL-R model using a BPTB graft, incorporating key surgical outcomes such as orientations-architecture and positions-dimensions of the tunnels, as well as a custom-made SG based on patella anatomy (3) TKA model considering custom-made CS implants with symmetric tibial bearing design. Before printing, mechanical uni-axial tensile tests of materials were conducted using an Instron S3300, following the ASTM designation D412-C. The printing materials selection process and matching with anatomical structures were based on the analysis of the mechanical pattern of the strain-stress curves from different combinations of Agilus30™. The Stratasys J750™ printer was used to manufacture the ACL-R model (previous study), the ACL-R model with SG, and the TKA model.
The combinations No. 1-4 were chosen for 3DP with elastic modules of 1.8-0.7 MPa and Pearson coefficients of 0.980-0.991 respectively. The PSAMs were tested manually simulating 50 flexo-extension cycles without presenting ruptures, custom-made SG matches perfectly with PT anatomy.
Functional PSAMs were printed with high fidelity, considerable cost, and short duration from planning to manufacturing. These coincided completely with 3D computer-generated PSAMs replicating fibers and features of the Knee Joint anatomy. The proposed PSAMs can be considered as an alternative to replacing cadaver specimens for medical training, pre-operative planning, education purposes, and validation of predictive models. We highlight the potential of PolyJet manufacturing combined with specialized medical software as a path to change the way specialists and researchers plan, execute, and validate complex procedures.