2018 HONORABLE MENTION

Two-stage revision is commonly performed for the management of a septic total knee arthroplasty (TKA) implant. Spacers play a crucial role in this surgical technique. This video describes the indications for, surgical technique for, and outcomes of two-stage revision TKA with the use of static spacers and two-stage revision TKA with the use of articulating spacers.

Static spacers are indicated in patients with severe ligamentous instability, wound healing problems, an insufficient extensor apparatus, or massive bone loss. The main disadvantages of static spacers are the risk of joint stiffness, poor range of motion, and increased bone loss during the second stage of the procedure. Static spacers are prepared using two Steinmann pins that are covered with antibiotic-loaded cement and used as intramedullary rods. A U-shaped posterior block made with antibiotic-loaded cement is prepared and positioned posteriorly to maintain joint tension. The previously prepared rods are inserted, and the construct is covered with antibiotic-loaded cement. A small amount of antibiotic-loaded cement also is applied in the suprapatellar pouch to prevent scar formation between the femur and the extensor apparatus.

Articulating spacers are most often used for two-stage revision TKA. In some patients, such as those with wound healing problems or extensor apparatus incompetence, a static spacer may be more strongly indicated. Articulating spacers are classified based on the interface and include cement-on-cement spacers, prosthesis-on-polyethylene spacers, and metal-on-polyethylene spacers. Cement-on-cement spacers are most commonly used and can be molded or preformed. No clear advantages exist with regard to one type of spacer over another; therefore, the type of spacer used depends on surgeon preference. In this video, two-stage revision TKA is performed with the use of preformed spacers. Dislocation is a possible complication associated with articulating spacers. To prevent dislocation, two Steinmann pins can be covered with antibiotic-loaded cement and used as intramedullary rods.

Various studies have compared static and articulating spacers. No differences have been reported between static and articulating spacers with regard to the rate of infection eradication; however, articulating spacers are associated with better range of motion, decreased joint stiffness, and an easier second stage of the procedure compared with static spacers.