Rare Earth Metals as Alloying Components in Magnesium Implants for Orthopaedic Applications

Comparison of two pore sizes of LAE442 scaffolds and their effect on degradation and osseointegration behavior in the rabbit model

“…The LAE442 alloy has already been classified by in vivo studies as a biocompatible and slowly degrading bone substitute (Angrisani et al, 2012;Angrisani et al, 2016;Hampp et al, 2013;Meyer-Lindenberg et al, 2010;Reifenrath et al, 2010;Rossig et al, 2015;Thomann et al, 2009;Witte et al, 2005;Witte et al, 2006). So far, however, only solid implants from LAE442 have been investigated (Angrisani et al, 2016;Hampp et al, 2013;Krause et al, 2009;Meyer-Lindenberg et al, 2010;Reifenrath et al, 2010;Rossig et al, 2015;Thomann et al, 2009;Witte et al, 2005;Witte et al, 2006;Witte et al, 2010;Wolters et al, 2013).…”

“…In order to avoid or significantly reduce limited mechanical stability and biocompatibility, more attention is being paid to bioresorbable bone substitutes consisting of magnesium alloys (Agarwal et al, 2016). The mechanical properties such as the Young's modulus (E = 41-45 GPa) and the density (1.74-1.84 g/cm 3 ) of magnesium (Mg) are similar to bone (E = 15-25 GPa/density = 1.8-2.1 g/cm 3 ) (Staiger, Pietak, Huadmai, & Dias, 2006), so the use of Mg as a bioresorbable metal can ensure long-term stability during the healing phase (Angrisani, Seitz, Meyer-Lindenberg, & Reifenrath, 2012). At the beginning of the last century, investigations with Mg implants were already being carried out on humans and animals to analyse the degradation of pure Mg in the form of plates, screws, and pins (Lambotte, 1932;Mcbride, 1938;Verbrugge, 1933;Verbrugge, 1934).…”

“…The corrosion behavior of Mg could be slowed down by adding various elements such as aluminum (Al), zinc (Zn), lithium (Li), and rare earth elements (SE). This resulted in better primary stability with good biocompatibility (Angrisani et al, 2012;Angrisani et al, 2016;Hampp et al, 2013;Höh et al, 2009;Lalk et al, 2013;Lalk, Reifenrath, Rittershaus, Bormann, & Meyer-Lindenberg, 2010;Meyer-Lindenberg et al, 2010;Rossig et al, 2015;Thomann et al, 2009;Witte et al, 2005;Witte et al, 2006;Witte et al, 2010). Compared with Al-Zn alloys (AZ91, AZ31) and an alloy with yttrium and rare earths (WE43) (Witte et al, 2005), the Mg alloy LAE442 (90 wt% Mg, 4 wt% Li, 4 wt % Al, 2 wt%) has proven to be a promising implant in various animal studies with regard to its good mechanical stability and biocompatibility (Angrisani et al, 2012;Angrisani et al, 2016;Hampp et al, 2013;Meyer-Lindenberg et al, 2010;Reifenrath et al, 2010;Rossig et al, 2015;Witte et al, 2005;Witte et al, 2006;Witte et al, 2010).…”

Electrochemical Analysis and In Vitro Assay of Mg-0.5Ca-xY Biodegradable Alloys

“…Although an improvement of both the mechanical properties and the corrosion behavior for an appreciable number of alloys was attained, the biocompatibility did not follow the same trend [15], controversial experimental data being reported about effects and toxicity of REs [15][16][17][18][19]. Because REs are mixtures of some lanthanides in various chemical compositions, a way to better control the effects of such elements on the biocompatibility of Mg-REs alloys is to use only one of the elements as alloying element in biodegradable Mg alloys [16]. From REs group besides lanthanides there are Y and Sc [16] which can have similar effects on the microstructure and properties of Mg alloys with those of lanthanide mixtures [20][21][22][23][24][25][26].…”

“…Mg-rare earths (REs) alloys from binary, ternary, and quaternary system alloys were investigated regarding the mechanical properties and the corrosion behavior, as well as from the biocompatibility point of view [15]. Although an improvement of both the mechanical properties and the corrosion behavior for an appreciable number of alloys was attained, the biocompatibility did not follow the same trend [15], controversial experimental data being reported about effects and toxicity of REs [15][16][17][18][19]. Because REs are mixtures of some lanthanides in various chemical compositions, a way to better control the effects of such elements on the biocompatibility of Mg-REs alloys is to use only one of the elements as alloying element in biodegradable Mg alloys [16].…”