Real-implant articulating spacers for chronic knee prosthetic joint infection have similar infection control rates as all-cement spacer constructs.

Abstract

Antibiotic eluting cement spacers are commonly used to treat prosthetic joint infection (PJI) in the setting of knee arthroplasty, however, controversy exists regarding the optimal spacer design. The purpose of this study was to evaluate: 1) post-operative 30-day complications; 2) reoperations over the study period; 3) and ultimate infection control between real-implant versus all-cement spacers in the setting of two-stage revision treatment for chronic knee PJI. We hypothesize that complications and infection control outcomes will be similar between spacer constructs. This is a retrospective, tertiary referral, single-center analysis. Inclusion criteria included: chronic knee prosthetic joint infection undergoing planned two-stage revision, and minimum 1-year follow-up (mean 43 months) (N = 46 patients). Demographics, infection characteristics, surgical characteristics, and spacer type were collected. Multivariable logistic regressions evaluated associations of underlying demographic and treatment characteristics with outcomes. 30-day post-operative complication rates were not different between real-implant and all-cement spacer groups. In the real-implant group, 10/29 patients (34.5 %) had 30-day complications compared to 5/17(29.4 %) of all-cement spacer group (OR 5.68; 95 % confidence interval 0.39 to 82.96; p = 0.723). Unexpected reoperations were also similar between the two groups with 7/17 (41.2 %) of the all-cement group and 9/29 (31 %) of the real-implant group undergoing an unexpected reoperation (OR:0.40; 95 % CI: 0.04 to 3.93; p = 0.065). Infection control at final follow up was similar between the two groups with 12/17 (70.6 %) of the all-cement group and 26/29 (89.7 %) of the real-implant groups achieving infection control (p = 0.100). We found that post-operative complications, unexpected reoperations, and infection control outcomes were similar between all-cement and real-implant spacers. These results suggest that real-implant spacers may not compromise infection control outcomes while possibly providing functional benefits to patients after Stage I treatment for chronic PJI.