Resorbable bone fixation alloys, forming, and post-fabrication treatments

Abstract

Metallic alloys have been introduced as biodegradable metals for various biomedical applications over the last decade owing to their gradual corrosion in the body, biocompatibility and superior strength compared to biodegradable polymers. Mg alloys possess advantageous properties that make them the most extensively studied biodegradable metallic material for orthopedic applications such as their low density, modulus of elasticity, close to that of the bone, and resorbability. Early resorption (i.e., <3months) and relatively inadequate strength are the main challenges that hinder the use of Mg alloys for bone fixation applications. The development of resorbable Mg-based bone fixation hardware with superior mechanical and corrosion performance requires a thorough understanding of the physical and mechanical properties of Mg alloys. This paper discusses the characteristics of successful Mg-based skeletal fixation hardware and the possible ways to improve its properties using different methods such as mechanical and heat treatment processes. We also review the most recent work pertaining to Mg alloys and surface coatings. To this end, this paper covers (i) the properties and development of Mg alloys and coatings with an emphasis on the Mg-Zn-Ca-based alloys; (ii) Mg alloys fabrication techniques; and (iii) strategies towards achieving Mg-based, resorbable, skeletal fixation devices.

In Vitro Corrosion Assessment of Additively Manufactured Porous NiTi Structures for Bone Fixation Applications

“…The results confirm that the amount of the Ni ion released of the AM NiTi (dense structure) was similar to that for the conventionally fabricated NiTi. In addition, the AM porous structures (15,25,35 and 50% porosity) showed higher amounts of Ni ion release, which confirms the electrochemical corrosion results. For example, introducing 25% porosity increased the surface area from 594 mm 2 for bulk samples to 1997.5 mm 2 for the porous sample.…”

“…These impurities result in the formation of Ti-rich brittle phases, which affect the functional and structural properties of the material. Recently, Additive Manufacturing (AM) methods have been developed for the fabrication of metallic parts, including NiTi [24,25]. This near-net-shaping technology has been able to overcome the manufacturing limitations and has enabled the fabrication of complex geometries, such as scaffolds and porous structures [5,24,26].…”

Effect of Glue and Temperatures on Mechanical Properties of Starch-Based Biodegradable Composites Reinforced with Bagasse Fibers

“…excellent biocompatibility for biomedical application). However, their lower mechanical properties and poor long-term stability limit their use for such applications [3]. For instance, TPS has very low | mechanical properties (e.g.…”

Clinical, industrial, and research perspectives on powder bed fusion additively manufactured metal implants

“…calvarial defect model, however the rate of resorption remained sufficiently high that voids were observed between the implant surface and mineralised bone after 84 days [191]. Magnesium alloys have been the most widely used resorbable alloys [192,193], and as a result a wide range have been processed by L-PBF, including pure Mg, WE43, AZ91 and several Mg-Zn alloys [167,189,190,[194][195][196][197][198][199][200]. When produced by conventional means, Mg alloys and particularly pure Mg show low tensile strength, of the order of 30 MPa when cast, requiring heat treatment as a result [192].…”