DOI: 10.1097/01.idc.0000227707.50518.46

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Issn Print: 1056-9103

Publication Date: 2006/07/01


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Infected Total Knee Arthroplasty-When to Salvage, When to Remove: Procedures and Outcomes

Joseph R. Lentino

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In this issue, Hayakawa and Nakagawa1 report a retrospective analysis of the outcome of 22 patients treated at their hospital for infected total knee arthroplasty (TKA) for a 17-year span. In their hands, salvage of the prosthesis by incision and drainage and antibiotic therapy was possible in 6 patients, all of whom underwent early joint irrigation within 6 days of onset, with one exception who presented on day 14 and was taken immediately to surgery. None had methicillin-resistant Staphylococcus aureus (MRSA); 2 were infected by streptococci-one in group A and the other in group B; 4 had methicillin-susceptible S. aureus. No patient who was treated successfully had radiological evidence of periprosthetic loosening. All 22 patients were treated by continuous irrigation for 2 weeks before the decision to remove the prostheses was considered.
Five of the patients had a successful 2-stage revision. Second-stage revision procedures ranged from 3 to 47 months after removal of the infected prostheses. Successful revisions were accomplished in patients including those infected with MRSA or gram-negative enteric aerobic organisms. Revision with relapse was seen in an additional 3 patients, with relapse occurring between 6 weeks and as long as 6 years after reimplantation, highlighting the importance of long-term follow-up for patients. Arthrodesis was performed on 4 patients with S. aureus, 3 of whom had MRSA infection; the duration of infection from onset to implant removal was from 3 to 52 months. Delay in treatment often reduces options for therapy.
Two patients had resection arthroplasty-one culture negative and the other with MRSA. Finally, 1 patient with an infected joint required amputation to prevent sepsis after a prolonged 23 year-span. Death occurred in a single patient with Escherichia coli sepsis from the infected TKA.
The authors point out the following factors favoring successful salvage of the TKA: (1) a short interval from onset of infection to irrigation (less than 2 weeks), (2) no loosening of the prostheses, (3) infection with antibiotic-susceptible organisms, and (4) absence of prolonged postoperative exudates or joint swelling.
In their hands, any patient not responding to antibiotics and continuous irrigation within 2 weeks was not likely to salvage the prosthesis. Although irrigation and antibiotic therapy are favored because of the simplicity of the approach, not every patient is a viable candidate.
The decision to remove an infected knee prosthesis must be made within the context of the individual patient's response to conservative therapy, the desired outcome (ie, can the patient be ambulatory or are they incapacitated by comorbid conditions?), and the virulence of the organism.
Although the number of patients reviewed in this study was small, the authors' experience was in keeping with the literature.2 Approximately 2.0% of all patients with primary TKA developed infection,3 and of those resected with 2-stage revision, 62.5% (5 of 8) had a successful outcome. The reported percentage of patients who responded to debridement with irrigation and antibiotics was in keeping with that reported in the literature.4,5
Although the surgical aspects of revision resection, arthrodesis, and continuous irrigation are of importance and interest, the authors omitted any mention of antibiotic therapy used with the exception of amikacin-impregnated cement. Although details of medical management are scarce, the authors have correctly concluded that longer duration of infection precludes successful implant salvage. What they did not consider was the use of long-term oral suppression for patients who are too debilitated to undergo even the simplest noninvasive surgical procedure.
Given the frequency of TKA infection, it is inevitable that individual physicians will manage a few of these patients. Referral to orthopedic surgeons with the breadth of experience described by these authors will facilitate the best possible outcome for their patients.
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