Two-stage exchange knee arthroplasty: Static spacers

Antibiotic spacers are an important tool in the management of periprosthetic joint infection. The concept of spacers has evolved from a static block in which the knee is immobilized in full extension to more conforming articulating surfaces that allow more knee motion, in an attempt to improve patients' quality of life before and after reimplantation. Static spacers are still indicated in knees with significant bone and soft tissue compromise to avoid complications related to mobility in the absence of the proper amount of constraint. Increasing the amount of antibiotics added to the cement results in a higher and longer elution but could lead to potential systemic toxicity. It also reduces the mechanical strength of cement which becomes a concern if mobility and weight bearing are to be permitted. The ideal dose of antibiotics to be mixed with cement remains unclear. Large doses have been demonstrated to be clinically safe, but have not shown to be cost-effective in providing better infection control.