One-Stage Revision

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Two-stage exchange is considered the gold standard for treatment of chronic infection after total knee arthroplasty (TKA). However, a one-stage exchange may be an alternative to provide infection control and better knee function. In our experience, routine one-stage revision has not been associated with a higher rate of infection recurrence, but knee function was not improved compared with the results of two-stage revisions. One-stage exchange may be a reasonable alternative for some patients with chronically infected TKAs, improving their quality of life and reducing hospital costs.

Introduction

Infection after TKA is a devastating complication that threatens life and function. With the use of modern prophylactic measures, a low incidence of postoperative infection (1% to 2%) is to be expected. However, with the increasing number of TKAs performed, the number of infections will increase in proportion.

Treatment of infected TKAs usually requires surgery. Débridement should be performed only for early-stage infections. For chronic infection, prosthesis removal is considered mandatory. Implantation of a new prosthesis usually is performed in a subsequent stage after a variable waiting period (i.e., two-stage protocol) for healing of the infection. The period without any implant in place theoretically allows better control of the infection with systemic antibiotic therapy, but the patient must endure functional impairment during this period, and the final outcome may be poorer.

One-stage reimplantation was first proposed by Wroblewski. The theoretical advantage is that this approach suppresses the waiting period before reimplantation and improves the final functional outcome. It also avoids the need for a second demanding procedure with inherent risks of complications, including the occurrence of a new infection. However, the one-stage procedure has a higher risk of persistent or recurrent infection due to deficient débridement or insufficient antibiotic treatment.

Two-stage protocols are considered the gold standard for the treatment of infected TKAs. One-stage procedures usually are considered contraindicated or reserved for selected cases (e.g., those with no fistula, no severe bone damage, and a known pathogen with high sensitivity to antibiotics). However, only limited, nonprospective studies have addressed these issues, and systematic literature analyses have been inconclusive.

A routine one-stage protocol that includes prolonged oral antibiotic treatment may be applied to all cases of chronically infected TKA except for fungal infections and repeat failures of previous infection treatments. This chapter presents this protocol, with its important points and pitfalls, and compares its results with those reported in the literature.

Indications and Contraindications

At our institution, a routine one-stage protocol is used for almost all cases of chronically infected TKA, provided that certain conditions are met. There are few contraindications:

• Cases of early postoperative infection are considered for débridement with implant retention when the surgical treatment is performed up to 6 weeks after the index implantation.

• Cases of hematogenous infection are considered for débridement with implant retention when the surgical treatment is performed up to 7 days after the onset of the symptoms.

• Fungal infection is routinely treated with a two-stage procedure.

• Repeat failure of TKA exchange (one or two stage) is routinely considered for a two-stage protocol.

All other cases are typically treated with a one-stage prosthesis exchange. In selecting patients, we do not take into account the classic contraindications for such a protocol, such as fistula, resistant pathogen, poor medical status, or extensive bone destruction. The only contraindication might be a chronic infection with a pathogen (e.g., fungus) with virtually no possibility of prolonged antibiotic treatment. However, these cases are rare.