A review on the utilization of SS 316L lattice structures for orthopaedics developed by the laser powder bed fusion process

Abstract

Stainless Steel 316L (SS316L) is widely used in orthopaedics due to its biocompatibility, affordability, ease of fabrication, adequate mechanical strength and corrosion resistance. Despite its many benefits, the stiffness of SS316L has been a significant cause for concern since it causes stress shielding and implant failure. A potential solution for stress shielding in orthopaedic implants is lattice SS316L, which can be fabricated using the laser powder bed fusion (LPBF) process. The development of lattice structures using the LPBF process allows the scaffolds to adhere, grow and differentiate bone cells with specific mechanical properties suitable for bone implants. The study highlights different lattice structures employed in orthopaedic implants, mainly focusing on the gyroid structures and delves into the fabrication of SS316L lattice structures. Compared to traditional solid implants, the TPMS SS316L gyroid showed at least a 30%–70% improvement in weight reduction, reduced stress shielding by 80%, material saving and a 10%–20% improvement in biocompatibility and 50%–200% osseointegration. Compared to other porous metallic implants, there was a 10%–15% improvement in the compressive and tensile strengths. A 10%–20% at reduced weight concerning strength-to-weight ratio and 40% economically viable. The review also highlights the influence of various lattice parameters on the mechanical and biological attributes of lattice structures, emphasizing the benefits of gyroid lattice structures and their potential impact on the Orthopaedics sector. Furthermore, by leveraging the unique properties of gyroid lattices, SS316L offers a promising solution for stress shielding in orthopaedic implants, with an affordable and compatible alternative to titanium implants in orthopaedics.