Additively Manufactured Partially Porous PAEK Topologies for Proximal Tibia Revision Cones and Sleeves

Metaphyseal cones and sleeves are an increasingly common component utilized in revision total knee arthroplasty. These partially porous devices have a high surface area and aim to integrate with cancellous bone of the distal femur and proximal tibia to increase the stability of the implant. Incidences of metal-hypersensitivity and macrophage-stimulated osteolysis have motivated the development of a non-metal alternative in the form of   polyaryletherketone (PAEK) implants. We hypothesized that highly complex porous PAEK components could be additively manufactured to withstand the mechanical forces of the knee, while still allowing for bone ingrowth. Taguchi optimization was used to investigate parameters and porous geometries that achieved the highest ultimate load in 45° shear-compression. Micro-CT was used to evaluate the quality of the print porosity for each experimental group. Low-melt (LM) PAEK sample means exceeded all polyetheretherketone (PEEK) means, and geometry and percent porosity were found to be the most significant parameters for LM PAEK, while nozzle temperature, chamber temperature and layer height were the most significant for PEEK (p < 0.05). All samples passed the theoretical worst-case scenario of ~ 5.5 kN ultimate load in 45° shear. The mean errors for percent porosity were not significantly different (p > 0.05) and measured to be - 8.46% and - 12.25% for PEEK and LM PAEK groups, respectively. This work serves as a proof-of-concept for 3D printing highly porous non-metal metaphyseal sleeves/cones without compromising on strength.