No difference in failure between static, articulating, and prosthetic low-friction spacers for periprosthetic joint infection of total knee arthroplasty.

Abstract

Introduction: Two-stage revision with an antibiotic spacer is the gold-standard treatment of prosthetic joint infection (PJI) for total knee arthroplasty (TKA). Multiple spacer designs exist, including static, articulated, and prosthetic low-friction (PALF) spacers. However, current literature is limited on variant superiority for infection eradication. This study aimed to compare outcomes of two-stage exchange for TKA PJI between patients with static cement, articulated cement, and PALF spacers. Methods: This retrospective study included 93 patients who underwent two-stage revision for PJI following primary TKA and received a static ( $n=17$ ), articulating ( $n=54$ ), or low-friction ( $n=22$ ) spacer. The primary outcome was failure at 2 years, defined as spacer retention, reoperation, or death. Secondary outcomes included reimplantation and discontinued antibiotics by 1 year, time to failure, duration of hospital stay, functional measures, and adverse events. Outcomes were compared between groups using hypothesis testing for continuous or categorical measures. Results: At 2 years, no significant difference in failure was seen for static (58.82 %), articulating (35.19 %), and PALF (22.73 %) spacers ( $p=0.064$ ). Articulating spacers demonstrated greater range of motion than static spacers at the final follow-up ( $p=0.0$ 3). Static spacers were associated with a higher adverse-event frequency ( $p=0.03$ ). No other significant differences in outcomes were observed (all $p>0.05$ ). Conclusions: The three spacer variants demonstrated similar failure rates for two-stage revision of TKA PJI at 2 years. Static spacers may lead to adverse events more frequently compared to other designs, and a longer interstage duration for prosthetic spacers may reflect greater functionality.