Surgical wounds are classified as clean, clean-contaminated, contaminated, and dirty/infected prior to surgery in order to estimate the overall risk of postoperative infection (Table 10.1). Preoperative antibiotic prophylaxis has proven effective in the prevention of wound infections; however, it has a minor effect in comparison with environmental and patient host factors.

In addition to proper prophylaxis when indicated, several surgeon-dependent factors may minimize infection risk. Firstly, confirming adequate preoperative skin preparation reduces the risk of surface contamination. The risk of surgical site infection is significantly increased if site contamination with greater than 10⁵ microorganisms per gram of tissue is present. Infection may ensue with concentrations of less than 100 microorganisms per gram of tissue when foreign material is present at the site, that is, foreign body, implants, or sutures (3).

Shaving preoperatively has been the topic of much debate. The 1999 Guidelines by the Centers for Disease Control and Prevention recommend that hair is not removed unless the hair present will interfere with the operation, and when removed, it should be done with electric clippers, immediately before the procedure. Minimizing dead space via meticulous anatomic dissection and layered closure will minimize hematoma and seroma, eliminating a potential nidus for infection. Drains should be used when indicated. Careful tissue handling minimizes late tissue necrosis and wound dehiscence.

Copious wound irrigation lessens the risk of retained foreign material and nonviable tissue or bone, again eliminating these factors as a potential source for infection. Antibiotic irrigation solution is often employed but has not been significantly researched. Its application is limited by such factors as volume of irrigation required, proper pressure and flow patterns, antibiotic concentration, local drug availability, and drug selection (4). Of late, the popularity of antibiotic-coated implants has grown; however, no clinical trials have been completed to date to prove their efficacy in preventing postoperative infection. Podiatric applications are not yet available, but preliminary research has been completed in the use of coatings on external fixation wires (4).

The surgeon is also responsible for keeping informed on hospital trends, local flora, and sensitivity patterns (5). These measures, along with appropriate antibiotic prophylaxis, significantly reduce the risk of postoperative infection as well as the length of hospital stay and associated costs.

The appropriate indications for preoperative antibiotic prophylaxis have been long debated. First, patient factors must be taken into consideration. Infection rate increases with age. Poor nutritional status also raises the incidence of postoperative infection. Obesity raises the risk of infection, though the mechanism is unclear. Surgery, in itself, can impair the immune system to some degree, having placed the host under significant stress during anesthesia (1,3) (Table 10.2). Prophylaxis is consistently recommended in all cases classified as clean-contaminated, contaminated, and dirty (1). Prophylactic intravenous (IV) antibiotics are not indicated in clean elective cases where no prosthetic material is being placed unless the patient meets certain high-risk criteria (Fig. 10.1). Also, studies have shown that the preoperative antibiotic prophylaxis is not indicated in arthroscopic surgical procedures (Table 10.3).

Any patient undergoing surgery that is expected to last more than 2 hours should receive prophylaxis because as operating time increases, more bacteria are introduced by operating room personnel, by the operating room environment, and from the patient’s own flora. Immunocompromised patients, that is, those with uncontrolled diabetes mellitus, receiving long-term immunosuppressive drugs, or those with genetic or acquired immune defects, should always be prophylaxed. Trauma surgery patients should be prophylaxed due to the high risk of the presence of devitalized tissue (Fig. 10.2). The reduction of high-energy closed fractures and reduction of open fractures are associated with an infection rate of 5% to 15%. This risk is reduced to less than 3% with the proper use of prophylactic antibiotics (6).

Patients receiving a form of prosthetic implant should also be prophylaxed to discourage the formation of a bacterial “slime” layer on the surface of the implant. Lastly, prophylaxis is
always indicated when the risk of postoperative infection would be devastating to the outcome and overshadows the risks of antibiotic therapy (3).

Prophylaxis against bacterial endocarditis is not warranted in clean orthopaedic procedures but is indicated in incision and drainage procedures for severe foot infections when sepsis is of concern. In these patients, intubation increases the risk of introduction of infectious organisms into the retropharyngeal space (7).