Infections involving orthopaedic surgical implants present unique challenges when compared with infections that do not involve implants. Microorganisms have a high affinity for adhering to foreign materials commonly used in orthopaedics, including cobalt-chromium, titanium, polyethylene, and polymethylmethacrylate (PMMA) cement. When bacteria adhere to these surfaces, they can form a complex structure surrounded by a self-generated extracellular polymeric substance(EPS) matrix formed by multiplex agents of biopolymers consisting of proteins, polysaccharides, lipids, nucleic acids,
and humic substances. The term “biofilm” is commonly used to describe this network of microorganisms, a term popularized by Dr. J. William Costerton et al. in 1978.

Biofilms are formed by a confluence of bacteria commonly encountered in orthopaedic infections. Up to 65% of bacterial infections are caused by biofilm-producing organisms. Staphylococci, specifically Staphylococcus aureus(S. aureus) and Staphylococcus epidermidis (S. epidermidis), are the most common biofilm-forming bacteria found in orthopaedics, and, when combined with Pseudomonas aeruginosa(P. aeruginosa), they represent nearly 75% of biofilm infections observed in medical devices. Propionibacterium acnes(P. acnes), an organism commonly found in shoulder infections, has also been shown to form biofilm. Biofilms can be composed of a single organism or can be polymicrobial; polymicrobial biofilms are more difficult to eradicate.