Biofilms and Aseptic Loosening

Orthopaedic implants play a remarkable role in maintaining health and mobility. Unfortunately, implanted orthopaedic devices sometimes fail owing to a variety of factors, one of the most important of which is bacterial infection. However, in a significant proportion of cases, failure can not be clearly attributed to infection based primarily on the inability to isolate an offending bacterium. Such failures are often referred to as “aseptic loosening”. There is an ongoing debate as to whether at least some of these cases may in fact have an infectious etiology. If so, then there must be some explanation for why current diagnostic methods fail to detect the underlying infection. This is a critical debate in that the failure to detect infection necessarily compromises the ability to utilize the most appropriate antimicrobial therapy. This chapter summarizes the clinical issues surrounding aseptic loosening and discusses the possible reasons why conventional culture techniques may fail to detect infection.