Treatment of Infected Total Knee Arthroplasty Using an Articulating Spacer

Abstract

Fifty consecutive patients with late infected total knee arthroplasties were treated by debridement and removal of all components and cement, preserving the collateral ligaments. At the time of debridement, an articulating spacer was made to allow partial weightbearing and range of motion of the knee during rehabilitation. This spacer was implanted using antibiotic-impregnated bone cement. For this purpose, 4.8 g powdered tobramycin was mixed with 40 g Simplex cement. Cement was applied early to the components, but applied late to the femur, tibia, and patella to allow molding to the defects and bone without adherence to bone. Patients had tailored intravenous antibiotic therapy for 6 weeks for treatment of various gram-positive and gram-negative organisms. All patients had cemented revision total knee arthroplasty using antibiotic-impregnated cement with standard cementing techniques. Range of motion before reimplantation was 6 degrees -91 degrees . Followup averaged 73 months (range, 24-150 months). The average modified Hospital for Special Surgery knee score after revision was 89 points (range, 70-100 points) with 90% good to excellent results, excluding the results of patients with reinfection. Range of motion after reimplantation was 4 degrees -104 degrees. Six patients had recurrences of infection, and one patient with a poor postoperative range of motion had a fusion. Use of an articulating spacer achieved soft tissue compliance, allowed for ease of operation, reduced postoperative pain, improved function, and eradicated infection equal to standards reported in the literature. Therapeutic study, Level IV (case series-no, or historical controls).