Antiseptics and antibiotics on implants

Abstract

Incidences of infection following elective orthopedic surgery are low and range from 0.7−4.2%, depending on the type of operation, soft-tissue status, general patient condition, and prophylactic use of antibiotics. Patients with open fractures clearly show a higher risk of infection (5−33%) due to bacterial contamination and soft tissue damage. The consequences of such infections can be devastating, leading to prolonged hospitalization, poor functional outcome, and sepsis. Bone infections associated with foreign bodies such as prostheses or osteosynthetic devices are especially difficult to treat. Procedures frequently required include removal of the infected device, long-term systemic antibiotic therapy with possible side effects, and multiple revisions with radical debridement. Systemically administered antibiotics are necessary and effective in therapy in addition to surgical revision. A serious problem is the increasing number of implants infected by (methicillinresistant Staphyloccus aureus) MRSA and chronic Staphyloccus epidermidis. Due to disturbed tissue function caused by surgical trauma at the implant/tissue interface, bacteria seeded during surgery may cause later infection. Mainly S. epidermidis, but also certain strains of S. aureus, tend to produce an extracellular polysaccharide matrix (biofilm) if they attach to foreign body surfaces. Biofilm formation makes eradication of these microorganisms nearly impossible without removing the implant. S. aureus and coagulase negative staphylococci (S. epidermidis) can be isolated from deep wound infections in up to 70−90% of cases. Systemic perioperative application of antibiotics is routinely performed in orthopedic and trauma surgery, the efficacy of which has clearly been proven. High levels of tissue protection are achieved during surgery to prevent deep wound infection caused possibly by contaminating bacteria. In addition to systemic prophylaxis, various local antibiotic delivery techniques are in clinical use to reduce the rate of infection (antibiotic-loaded bone cements, antibiotic-impregnated collagen sponges or polymethylmethacrylate beads). Local application of antibiotics is advantageous in that high levels can be achieved around the implant without systemic toxicity. However, low drug levels provided over a long period could be disadvantageous and might cause the development of drugresistant bacterial strains. In several in vitro and in vivo studies and first clinical cases, it has been proven that locally delivered gentamicin from a biodegradable poly (D, L-lactide) (PDLLA) coating of implants with an initial burst release at high concentration could be an effective supplement for prophylaxis of implant-related infection in orthopedic and trauma surgery. This new approach in addition to established systemic antibiotic prophylaxis could reduce the infection rate especially in open-fracture situations. Antiseptics and antibiotics on implants