Antibiotic-impregnated articulating cement spacer for infected total knee arthroplasty

Background: Standard treatment of chronic infected total knee arthroplasty (TKA) is a two-stage revision, the first step being placement of an antibiotic-impregnated cement spacer. Here we describe the results of a new technique (modification of the Goldstien's technique) for intraoperative manufacture of a customized articulating spacer at minimal cost and with relatively good conformity and longevity. Materials and Methods: Thirty-six infected knees underwent this procedure from June 2002 to May 2007. The technique consists of using the freshened femur and tibia interface as molds wrapped in a tin foil for manufacturing the two components of the spacer with antibiotic-impregnated methyl methycrylate cement. We used the spacer and the femoral component of the trial set of a TKA system to mold them to perfect articulation. We also reinforced the spacer with a K-wire scaffold to prevent fracture of the cement mantle in the last 21 cases. Results: All 36 knees showed excellent results in terms of infection control, mobility, and stability. There was significant improvement in the WOMAC and Knee Society Scores (20 and 39 points respectively). There were two fractures of the spacers in the initial 15 cases that did not have K-wire scaffolding but none in the last 21 that had reinforcement. Conclusion: This technique provides a more conforming spacer, with good range of motion and stability. The reinforcement helps in preventing the fracture of the cement mantle and is cost effective.