ABSTRACT
Institute of Pathology and Departments of Macromolecular Science and Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, U.S.A.
INTRODUCTION
The aimof this chapter is to provide practicing orthopaedic surgeons, scientists involved in joint replacement research and development, fellows, residents, and biomedical engineering students with an overview and an appreciation of the fundamental aspects of tissue/material interactions with emphasis on the inflammatory response and the foreign body reaction. In this overview, tissue/material interactions and the foreign body reaction are viewed from the classical medical perspective of the pathologist. Tissue/material interactions are commonly referred to as the tissue response continuum which is the series of responses that are initiated by the implantation procedure, as well as by the presence of the biomaterial, medical device, or prosthesis. In this chapter, we divide the series of tissue/material responses into the early, transient tissue responses and the late, persistent tissue responses. Early, transient tissue/material responses include injury, blood/material interactions, provisional matrix formation, temporal sequence of inflammation and wound healing, acute inflammation, chronic inflammation, and granulation tissue development. These responses are usually of short duration, occurring over the first 2-3 weeks following implantation of a medical device or prosthesis.
Late, persistent tissue responses include macrophage interactions, foreign body giant cell (FBGC) formation and interactions, and fibrosis and fibrous encapsulation of the medical device or prosthesis. The early, transient tissue responses form the basis for safety or biocompatibility considerations of the medical device or prosthesis. Late, persistent tissue/material responses, while important to the safety and biocompatibility considerations, may be more important in modulating the performance characteristics of the medical device or prosthesis as well as providing a biological basis for device or prosthesis failure such as osteolysis or loosening with total joint prostheses.
