Do Antibiotic Intramedullary Dowels Assist in Eradicating Infection in Two-Stage Resection for Septic Total Knee Arthroplasty?

Evidence suggests approximately 40% of intramedullary (IM) canals are culture positive at resection for infected knee arthroplasty. While commonly utilized, no clinical data on the efficacy of antibiotic-eluding IM dowels exist. We quantified treatment success with and without the use of antibiotic-eluding IM dowels in two-stage treatment of periprosthetic knee infection using static and articulating antibiotic cement spacers. 109 consecutive patients who underwent two-stage treatment for periprosthetic knee infection were reviewed. Treatment failure, defined as repeat resection before reimplantation or recurrent infection within 6 months of reimplantation, was evaluated based on spacer type and use of IM dowels, accounting for infection type and systemic host and local extremity grade. After exclusions for confounds, articulating spacers without IM dowels were used in 49 (57.7%) cases, articulating spacers with IM dowels in 14 cases (16.5%), and static spacers with IM dowels in 22 (25.9%) cases. Treatment success regardless of infection classification was 85.7% for articulating spacers with IM dowels, 89.8% for articulating spacers without IM dowels, and 68.2% for static spacers with IM dowels (P = .074). In chronically infected poor hosts with compromised extremities, treatment success remained highest in patients with articulating spacers with (90.9%) or without (92.9%) IM dowels compared with static spacers with IM dowels (68.4%) (P = .061). Findings suggest that the use of IM dowels did not enhance infection eradication above and beyond that observed for articulating spacers alone, including in the worst cases involving chronically infected poor hosts with compromised extremities.