Disease, trauma or serious infection may result in extensive bone damage or bone loss which exceeds the body’s capacity to repair itself. In such cases, implants are needed to promote satisfactory healing. These may take the form of screws, plates, or rods to immobilise broken bones in the correct alignment, reinforce weak bones or correct skeletal deformities. Similarly, diseased joints can be replaced with prosthetic joints to restore normal, pain-free movement.
Despite ongoing medical advances and improvements in materials and procedures, there remains a substantial risk of implanted devices becoming infected. In addition to microbes being introduced into the body during surgery, there is the risk of bacteria transported in the blood from other parts of the body colonising the surface of an implant.
It has been estimated that as many as 2.5% of primary hip and knee replacements and to 10% of joint revision surgeries are complicated by infection.1 Infected implanted devices represent a significant clinical challenge.
Typically, despite lengthy antibiotic treatments, it is often necessary for the infected implant to be surgically removed. This not only increases patient morbidity and dissatisfaction, but is also associated with substantial cost.2
Antibiotics continue to be the mainstay strategy for both the prevention and treatment of implant infections. However, the power of antibiotics in the fight against infection is diminishing as many strains of potent bacteria are developing resistance to even the strongest antibiotics. Consequently, the risk of implanted devices becoming infected is on the rise and researchers are investigating novel ways to reduce such infections.
One strategy is based on the discovery that the majority of bacteria live in surface-bound microbial communities, rather than as free-swimming entities. On binding to the surface, bacteria secrete adhesion proteins that provide an irreversible attachment.3 Such bacterial biofilms account for over 80% of clinical microbial infections.2
It was therefore proposed that making the surface of implants unsuitable for bacterial colonisation would dramatically lower infection rates. This can be achieved by coating the implant with bioactive glass.
Image Credit: Adobe Stock