Infection after total knee arthroplasty - A retrospective study of the treatment of eighty-one infections

Background: The clinical presentation of an infection at the site of a tota l knee arthroplasty can be used as a guide to treatment, including the deci sion as to whether the prosthesis should be retained or removed. We reviewe d the results of treatment of infection after total knee arthroplasty to ev aluate the effectiveness of four treatment protocols based on the clinical setting of the infection. Methods: We retrospectively evaluated the results of treatment of eighty-on e infections in seventy-six consecutive patients who either had an infectio n after a total knee arthroplasty or had multiple positive intraoperative c ultures of specimens of periprosthetic tissue obtained during a revision to tal knee arthroplasty performed because of presumed aseptic loosening. The patients were managed according to one of four protocols. Five infections i n five patients who had positive intraoperative cultures were treated with antibiotic therapy alone. Twenty-three early postoperative infections in tw enty-one patients were treated with debridement, antibiotic therapy, and re tention of the prosthesis. Twenty-nine late chronic infections in twenty-ei ght patients were treated with a delayed-exchange arthroplasty after a cour se of antibiotics. Seven acute hematogenous infections in six patients were treated with debridement, antibiotic therapy, and retention of the prosthe sis. Seventeen infections in seventeen patients mere not treated according to one of the four protocols. Sixteen late chronic infections were treated either with an arthrodesis (five infections) or with debridement, antibioti c therapy, and retention of the prosthesis (eleven infections). One acute h ematogenous infection was treated with resection arthroplasty because of li fe-threatening sepsis. Results: The mean duration of follow-up was 4.0 years (range, 0.3 to 14.0 y ears). Eleven patients who had an arthrodesis, a resection arthroplasty; or an above-the-knee amputation after less than two years of follow-up were i ncluded in the study as individuals who had a failure of treatment. In the group of patients who were managed according to protocol, the initial cours e of treatment was successful for all five infections that were diagnosed o n the basis of positive intraoperative cultures, five of the ten deep early infections, all thirteen superficial early infections, twenty-four of the twenty-nine late chronic infections, and five of the seven acute hematogeno us infections. Only one of eleven prostheses in patients who had a late chr onic infection that was not treated according to protocol was successfully retained after debridement. Conclusions: Our treatment protocols, which were based on the clinical sett ing of the infection, were successful for most patients. A major factor ass ociated,vith treatment failure was a compromised immune status. Bone loss a nd necrosis of the soft tissues around the joint also complicated the treat ment of these infections.