Use of Static Spacers in Periprosthetic Knee Infections
Background: Periprosthetic joint infection (PJI) remains a significant complication of total knee arthroplasty (TKA), with incidence rates reaching 8% in revision cases. While debridement, antibiotics, and implant retention (DAIR) may be utilized for acute presentations, chronic infections typically necessitate a two-stage exchange arthroplasty, which is currently the clinical standard.
Objective: This review evaluates the mechanical and antimicrobial properties of antibiotic-impregnated cement spacers, compares the clinical outcomes of static versus dynamic designs, and delineates specific surgical techniques and indications for static spacer utilization.
Key Points: Spacers maintain joint space, stabilize soft tissues, and deliver local antibiotic concentrations up to 700 times higher than systemic administration. Meta-analyses indicate that while infection eradication rates are comparable between spacer types (67%–100%), dynamic spacers offer superior postoperative range of motion and higher functional scores. However, static spacers are indicated in cases of severe bone loss, ligamentous instability, or extensor mechanism deficiency to prevent dislocation. Surgical success with static constructs requires intramedullary rod reinforcement with Kirschner wires and high-viscosity cement impregnated with heat-resistant, water-soluble antibiotics such as vancomycin and gentamicin. Methylene blue is recommended to facilitate cement identification during the second-stage reimplantation.
Conclusion: The selection between static and dynamic spacers must be tailored to patient-specific bone stock and soft-tissue integrity. Although dynamic spacers improve functional recovery and simplify surgical exposure during reimplantation, static spacers remain essential for managing complex cases with significant structural instability or profound bone loss.
