ABSTRACT
The influence of immunology pervades all aspects of medicine, from the vast numbers of diagnostic tests that employ antibody-mediated reactions to the treatment of organ graft rejection with T cell specific pharmaceutical agents. The direct effects of immunology upon the practice of orthopaedic surgery may not be immediately obvious, but the consequences of immune responses to implanted materials are requiring greater consideration with the evolution of the specialty towards advanced tissue engineering. Problems due to immunological effects upon orthopaedic implants and grafts are less obvious than those encountered in the early years of organ transplantation, but recent studies suggest that the immune system may readily undermine the benefits of skilled surgery. One casualty of the advance of immunology is the concept of ‘‘inert.’’ It is accepted that no foreign material can be implanted in the body without a biological response. The precise factors that determine whether the response becomes essentially benign or aggressively destructive remain to be elucidated, but these factors are becoming more understood with advances in immunological science. In this chapter, we will examine the mechanisms of normal immunity, and investigate how hypersensitivity to metal and polymer biomaterials, and responses to bone allografts which can contribute to the biological responses that result in implant loosening.
