Review Article The current trends of Mg alloys in biomedical applications—A review Usman Riaz, 1 Ishraq Shabib, 1,2 Waseem Haider 1,2 1 School of Engineering and Technology, Central Michigan University, Mount Pleasant, Michigan, 48859 2 Science of Advanced Materials, Central Michigan University, Mount Pleasant, Michigan, 48859 Received 25 April 2018; revised 10 November 2018; accepted 15 November 2018 Published online 00 Month 2018 in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/jbm.b.34290 Abstract: Magnesium (Mg) has emerged as an ideal alternative to the permanent implant materials owing to its enhanced prop- erties such as biodegradation, better mechanical strengths than polymeric biodegradable materials and biocompatibility. It has been under investigation as an implant material both in cardio- vascular and orthopedic applications. The use of Mg as an implant material reduces the risk of long-term incompatible interaction of implant with tissues and eliminates the second surgical procedure to remove the implant, thus minimizes the complications. The hurdle in the extensive use of Mg implants is its fast degradation rate, which consequently reduces the mechanical strength to support the implant site. Alloy development, surface treatment, and design modification of implants are the routes that can lead to the improved corrosion resistance of Mg implants and extensive research is going on in all three directions. In this review, the recent trends in the alloy- ing and surface treatment of Mg have been discussed in detail. Additionally, the recent progress in the use of computational models to analyze Mg bioimplants has been given special con- sideration. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res B Part B: 00B: 000–000, 2018. Key Words: biodegradation, alloy development, surface treat- ment, computational models How to cite this article: Riaz U, Shabib I, Haider W. 2018. The current trends of Mg alloys in biomedical applications—A review. J Biomed Mater Res B Part B. 2018:9999B:9999B:1–27. INTRODUCTION Magnesium (Mg) has emerged as a potential biomaterial owing to its biocompatibility, good mechanical strength, and biodegra- dation. Mg is nontoxic 1 in nature with the daily recommended intake of 240–420 mg/day for adults. 2 This value is almost 50 times higher than the recommended intake of Iron (Fe) and Zinc (Zn), which are other potential implant materials. 1 Addi- tionally, Mg and its alloys have shown excellent biocompatibil- ity in physiological conditions. 1,3–7 Along with biocompatibility, Mg has suitable mechanical properties for an implant material such as being light weight and having a good strength to weight ratio. 8,9 Moreover, the elastic modulus of Mg is about 45 GPa, which is closer to the elastic modulus of bone (3–20 GPa), reducing the possibility of stress shielding. 1 On the other hand, Fe and Zn have elastic modulus values of 211.4 and 90 GPa, respectively, much higher than that of bone. 1 Along with suit- able mechanical properties and biocompatibility, biodegrada- tion is the primary reason for the enhanced interest in Mg as an implant material. 7–13 Prolonged interactions of implants in the biological surroundings can lead to many complexities 10,13–15 and are not desirable. Mg alloy implants avoid these long-term incompatible interactions with the body tissues 15 eliminating the possibilities of any complexity. All the above-mentioned properties make Mg a potential material to replace the conven- tional permanent implant materials. The research on the potential of Mg as an implant mate- rial is not new as it has been under investigation in biomedi- cal applications since the late 1800s. 8 It is reported that Mg in medical applications was first employed by Edward C. Huse, who used Mg wires as ligatures to stop bleeding in 1878. 16 Later on, E.W. Andrew considered absorbable metal clips as an alternative to ligatures as they ensured the safety of hemostasis. 16 In 1900, Erwin Payr proposed the idea of using Mg as fixator pins, wires, plates, and nails. 16 Addition- ally, he did significant work on the biodegradation of Mg and proposed the factors responsible for its in vivo corrosion. 16 In 1906, Albin Lambotte treated a boy with a fracture in the lower leg by using a Mg plate with steel screws. 16 The degra- dation of Mg inside the body encouraged him to investigate Mg as a biodegradable implant. Later on, he successfully treated four children having supracondylar humerus frac- tures. 16 On the basis of successful results, Lambotte recom- mended the use of Mg implants in the treatment of several fractures and surgeries. 16 Jean Verbrugge, an assistant to Correspondence to: W. Haider; e-mail: haide1w@cmich.edu © 2018 Wiley Periodicals, Inc. 1