Real Component Spacers for Two-Stage Exchange Demonstrate Low Bacterial Colonization.

Background: Patients undergoing two-stage exchange arthroplasty for chronic periprosthetic joint infection (PJI) with real component spacers (RC) benefit from improved function. While RCs have similar reinfection rates compared to other spacer types, concerns exist regarding the potential for bacterial colonization and biofilm formation on the RC metal components.

Methods: Patients who completed two-stage exchange arthroplasty for treatment of Musculoskeletal Infection Society-defined hip or knee PJI were included and explanted spacer components were sent for sonication fluid culture (SFC). Medical records were reviewed for demographics, laboratory values, culture results, and clinical outcome data including 90-day reoperations and all-cause revisions.

Results: A total of 112 patients (57 hips and 64 knees) were included. Sixty (49.6%) patients received an articulating cement spacer (AC), 35 (28.9%) received an RC, and 26 (21.5%) received a static spacer (SS). No positive SFCs were identified with RC compared to 18.3% with AC and 11.5% with SS ( = .01). The number of positive tissue cultures was similar (RC 8.6%, AC 1.7%, SS 3.8%;  = .18). No patients who received an RC required repeat debridement within 90 days, while 11.8% with AC and 4.5% with SS required repeat debridement ( = .14). The difference in the rate of all-cause revision and revision due to recurrent infection among the 3 groups was found to be similar ( = .43 and  = .50, respectively).

Conclusions: RC showed fewer SFCs when compared to AC and SS, though there was no significant difference in positive tissue cultures, reoperation within 90 days, all-cause revision, or revision due to recurrent infection among the groups.