Biodegradable magnesium matrix composites for bone fixation devices

Abstract

When a bone is fractured, it loses its structural integrity which makes it unable to bear any mechanical load. Therefore, a broken bone must be supported until it regains its strength to handle the body's movement and weight. A surgical procedure is needed to set a fractured bone. This procedure often involves repositioning the bone fragments into their natural position and then, attaching them together using internal fixation devices such as plates and screws. These fixation devices restore load-beanng capacity to bone, allowing the fractured bone to be healed by the primary bone healing mechanism. To date, implants used for internal fixadon are usually made from titanium and stainless steel, which are strong but, notorious for triggering adverse reactions such allergic responses caused by implant erosion in patients. Therefore, permanent fixtures should be removed from the body after the fractured bone heals sufficiently, which imposes another invasive surgery on the patient. The advent of biodegradable magnesium-based composites about two decades ago was an attempt to address the clinical complications regarding the permanent fixtures. However, magnesium-based composites are still in their infancy, and a have a lot to achieve before being considered as fully functional materials for bone fixation purposes. Currently, there are two major issues with magnesium composites. Firstly, most of the magnesium-based composites made to date lack sufficient mechanical integrity, making them unsuitable for load-bearing applications. The second, and the most important, issue would be the rapid degradation of magnesium when exposed to physiological solutions, causing pre-mature mechanical failure before the patient fully recovers. The main aim of this thesis is to provide the necessary background and technical information to address these issues, and to be a reliable platform for future researches on the subject to build upon.