Carefully selected cases of prosthetic joint infection may be treated with simple surgical debridement of the joint with prosthesis retention and at least 3 months of antimicrobial therapy that includes rifampin if the organism is gram positive (44). Patients who present with a short duration of symptoms within 1 month of joint implantation, or those with acute hematogenous infection, are the best candidates for such a treatment strategy. Unfortunately, relapse is common in these cases, particularly if the infection is due to S. aureus, gram-negative bacilli, or drug-resistant pathogens. Thus, the optimal treatment protocols involve surgical excision of the infected prosthesis and prolonged antimicrobial therapy.
Surgical prosthesis extraction and reimplantation can be performed in either a one- or two-stage approach. The two-stage procedure is the more successful strategy and involves removal of the prosthesis and cement followed by a 6-week course of bactericidal antimicrobial therapy. Subsequently a new prosthesis is reimplanted. Using this approach, a 90% to 96% success rate in total hip replacement infections and a 97% success rate in total knee infections has been realized (45-47). An alternative tactic is a one-stage surgical procedure that excises the infected prosthesis with immediate reimplantation of a new joint using antibiotic-impregnated methacrylate cement. This method is effective in 77% to 83% of cases (48-50). Higher failure rates are observed for S. aureus and gram-negative bacillary infections (51). One-stage procedures are often used for elderly or infirm patients who might not tolerate protracted bed rest and a second major operation (52). A recent review article by Zimmerli et al. provides an excellent overview of antimicrobial and surgical treatment options for prosthetic joint infections (34).
Suppressive Antibiotic Therapy
Lifelong oral antimicrobial therapy plays a limited role for definitive therapy but is useful when a surgical approach is not possible because of medical or surgical contraindications. The goal of suppressive therapy is to control the infection and retain prosthesis function. It is important that patients and their families understand that the intention of such treatment is not to cure but to suppress the infection. Generally, oral suppressive therapy is initiated after a course of intravenous therapy. Goulet et al. (53) demonstrated a 63% success rate in maintaining function of hip arthroplasty in patients who met 5 criteria: 1) prostheses removal is not possible, 2) the pathogen is avirulent, 3) the pathogen is sensitive to oral antibiotics, 4) the patient is adherent to and tolerates antibiotics, and 5) the prosthesis is not loose. Patients being treated with lifelong suppressive therapy are at risk for the development of antibiotic resistance (in either the joint infecting pathogen or other commensal organism), local or systemic progression of infection, and adverse effects from chronic antibiotic usage.
Antimicrobial Prophylaxis to Prevent Joint Prosthesis Infection
Patients undergoing elective total joint replacement surgery should be evaluated for symptoms or signs of local infection that predispose to occult or overt bacteremia (particularly odontogenic, urologic, and dermatologic). Surgery should be delayed until such infections and coexisting medical conditions have been treated. Perioperative antibiotic prophylaxis has been shown to reduce deep wound infection and prosthetic joint infection in joint reimplant surgery but should not be continued for more than 24 hours after the preoperative dose (54,55). In order to decrease the risk of hematogenous seeding of established implants, early recognition and treatment of overt infection is crucial. The use of prophylactic antibiotics for patients with joint implants prior to or after dental or other procedures such as colonoscopy or cystoscopy is controversial. The American Academy of Orthopedic Surgeons recommends that a single dose of prophylactic antibiotic be given to certain patients undergoing urologic instrumentation or dental procedures that are accompanied by significant bleeding (56,57). Patients who are candidates for such prophylaxis include those with rheumatoid arthritis or other inflammatory arthropathy, immunosuppression, diabetes, malnutrition, hemophilia, or who have had a previous joint infection.