Influence of deformed primitive architecture on mechanical behavior of artificial porous meniscus

Abstract

Polycarbonate urethane (PCU) has emerged as a suitable material for artificial meniscus replacement after meniscectomy. However, the commercial PCU meniscal replacements could not reproduce native meniscus performance until now. The aim of this paper was to design porous permanent implants using the deformed primitives to better withstand the stress and transfer the load. Mechanical compression tests showed that higher volume fraction and function periodicities of primitive units will lead to denser structures which are stronger under loading. Finite element simulations were then conducted on ten different cases including intact healthy knees, knee joints with solid meniscal implants, and knee joints with meniscal implants with eight types of deformed primitive surfaces. Compression and shear stresses, stress concentrated areas and meniscal extrusion displacement were evaluated under the posture of balanced standing. Compared to the solid meniscal implant, the proposed porous implants reduced both stress extremes, stress concentration area and the displacement of meniscal extrusion. Meanwhile, the proposed PCU implants can be fabricated with 3D printing technology, indicating a good clinical application. Keywords: Meniscal implant, Porous structures, Polycarbonate-urethane (PCU), Triply periodic minimal surface, Mechanical properties, 3D printing