Magnesium Alloys for Open-Pored Bioresorbable Implants

Abstract

If bone defects occur, the body's own healing mechanism can close them below a critical size; for larger defects, bone autografts are used. These are typically cut from the same person's hip in a second surgery. Consequently, the risk of complications, such as inflammations, rises. To avoid the risks resulting from the second surgery, absorbable, open-pored implants can be used. In the present study, the suitability of different magnesium alloys as absorbable porous bone substitute material has been investigated. Using the investment casting process with its design flexibility, the implant's structure can be adapted to the ideal pore geometry with respect to bone ingrowth behavior. Different magnesium alloys (Mg-La2, LAE442, and ZX61) were studied and rated in terms of their degradation rate, bone ingrowth behavior, biocompatibility, and resorbability of the individual alloying elements.

In vivo investigation of open-pored magnesium scaffolds LAE442 with different coatings in an open wedge defect

“…Scanning electron microscope (SEM) images were taken of unstained histological sections prepared as described in 2.7 according to Maier et al 36 to characterize the surfaces of the scaffolds. Energy-dispersive X-ray spectroscopy (EDS) analyses were performed in selected areas to determine the composition of the elements.…”

“…[21][22][23] To further increase corrosion resistance, both Mg solids and bone substitutes are additionally coated. [36][37][38] MgF 2 has been reported in the literature to improve corrosion properties and has shown to be very biocompatible. 21,22,27,39,40 The use of an additional calcium phosphate (CaP) coating on the MgF 2 layer even provided additional corrosion protection.…”

The Potential of Calcium/Phosphate Containing MAO Implanted in Bone Tissue Regeneration and Biological Characteristics

“…Another advantage of the biodegradable properties of Mg alloys also avoid a second surgery for implant removal, which prevents additional medical therapy such as inflammation, increased sensitivity to pain and extra costs to the patients [ 8 ]. Most traditional metallic materials stay as an anchor in the body for a longer duration of time, leading to corrosion anomalies due to the degradation of the implanted product [ 9 ]. In the case of stents, contemporary stents are manufactured from stainless steel (316L), which has high corrosion resistance and remains as a permanent implant in the body.…”

Progress in partially degradable titanium-magnesium composites used as biomedical implants

“…Conventional implants, which have been extensively used for orthopedic applications and are constructed of Ti-based alloys ( Liu et al, 2019 ; Yan et al, 2019 ), stainless steel ( Brooks et al, 2017 ; Teo et al, 2021 ), and cobalt-based alloys ( Mas Ayu et al, 2019 ), will remain inside the body permanently after its implantation. Magnesium ( Maier et al, 2020 ; Wu et al, 2021 ; Zeller-Plumhoff et al, 2021 ) are also classified as implants as biodegradable materials, in addition to the metals indicated above. In general, stainless steels and Co-based alloys suffer from a major biological drawback.…”