High-strength and corrosion-controlled magnesium-based bone implants

H. Ibrahim
University of Tennessee Chattanooga,
United States

Keywords: magnesium, biodegradable, bone implants, coatings


Magnesium is a lightweight metal that is naturally present in the human body with a biodegradable nature in aqueous mediums. These properties make magnesium an attractive material for its use in various biomedical applications when the material is not recommended to stay permanently in the body, such as bone implants. The success in developing biodegradable (nonpermanent) implants is expected to result in a clinical breakthrough for bone fracture repair. We know that the permanent existence of stiff metallic parts (e.g., Ti-6Al-4V and 316L stainless) in the body after bone healing frequently results in detrimental reactions, including inflammation, possible infection, and bone resorption. Also, leaving the implant inside the body after healing may cause future bone fractures due to physical activities, especially in children, teenagers, and athletes. All these problems lead to pain, implant loosening, device failure, and the need for revision surgery. To this end, we have developed both a biocompatible magnesium alloy (Mg-Zn-Ca-Mn-based alloy) and a fabrication method (heat treatment and coating) that deliver a high-strength and corrosion-tailored material that can provide the needed stability during the healing period for bone implant applications, and subsequently degrade until vanished completely after the healing of tissues. In vitro and in vivo assessments of our magnesium alloy and fabrication method showed high levels of biocompatibility in terms of degradation and fracture healing. For instance, our animal studies, using New Zealand white rabbit utilizing a lateral femoral condyle model, showed no negative effects on bone formation, and no evidence of a strong or persistent inflammatory reaction. Our technology will be used by orthopedic surgeons to treat patients with bone fractures in a wide variety of anatomical locations such as jaws, skulls, and extremities. At this stage, we are focused on the craniomaxillofacial fixation (CMF) market. The global craniomaxillofacial fixation market was valued at USD $ 1,382.1 million in 2019 and is expected to grow at a rate of 7.2% from 2019 to 2026. It is estimated to reach a value of USD $2,208.8 million in 2026. In addition, the market size of bioresorbable materials is expected to register a growth rate of 7.8% through 2026, according to a new research report by Global Market Insights, Inc. This is attributed to the growing old age population in the US, which has contributed a major share toward the growth of bioresorbable bone graft materials.