Chapter 3 - Osseointegration Concepts of Trauma Fracture Fixation and Joint Replacement

Abstract

Bone fracture fixation is managed by trauma implants. Integration of the trauma implants is achieved by purchasing of trauma screws to the bone fragments to hold the implant at the fracture site. Effective osseointegration of the screws is associated with various geometrical and treatment parameters of the surface. Based on the insertion of screw through the cortical and trabecular bones, the screw design might be different. Screw threads are beneficial to be with maximal mechanical integration when purchasing to the bone. The shape of threads could be straight, parabolic, or tapered to enhance the mechanical stimulation of purchased bone tissue between the threads. The growth of the bone tissue through the surface of the screw could be biologically improved to promote the osseointegration of the screw to the trabecular bone. Joint replacements consist of various prostheses or components. Prostheses are articulated to provide natural ranges of motion at the affected joint and implanted to the bones to establish integration of the joint replacements to the bone and its stability in the long-term implantation. Osseointegration of the joint replacements is established by implanted prostheses by which the articulation performance of the joint replacements is achieved for a long-term use. Osseointegration of implanted prostheses is mechanically and biologically developed through the consideration of geometrical features at the contact surfaces with the bone to provide mechanical integration of the implanted prostheses. The design of these features is optimized to establish effective distribution and transferring of the physiological loads at the bone-prosthesis interface. On the other hand, biological integration of the implanted prostheses is supplemented by surface roughening, bioactive coating, or porous layering. In this chapter, trauma implants and joint replacements are reviewed in general aspects and their osseointegration challenges and requirements are discussed accordingly.