All-cement articulating spacers versus all-polyethylene tibial spacers with a metal femoral component in staged revision for prosthetic joint infection following total knee arthroplasty: Which has better outcomes?

Abstract

Periprosthetic joint infection (PJI) following total knee arthroplasty (TKA) is commonly managed with a two-stage revision that uses an articulating spacer. Limited research has compared the clinical effectiveness of different articulating spacers. This retrospective study aimed to compare the outcomes of two articulating spacer designs - all-cement articulating spacer and all-polyethylene tibial spacer with a metal femoral component - for PJI following TKA. Between 2015 and 2023, 139 patients underwent stage 1 of a two-stage revision for PJI following TKA at a large referral center. Of these, 47 received an all-cement spacer, and 92 received an all-polyethylene tibial spacer. Age, sex, comorbidities, pathogens, and complications were retrieved from medical records. Patient satisfaction was assessed in clinic by a standardized question on satisfaction (satisfied, dissatisfied, or indifferent). Statistical analyses were performed to compare outcomes between groups. Following stage 1 surgery, the all-polyethylene tibia group demonstrated higher patient satisfaction (P < 0.0001) and a lower rate of unplanned reoperation (16.3% vs. 34.0%; P = 0.030) and infection (13.0% vs. 34.0%; P = 0.007). There were no significant differences in post-stage 1 range of motion (P = 0.215) or ambulatory status (P = 0.351). Multivariate analysis demonstrated an increased odds of unplanned reoperation (adjusted odds ratio (OR) = 2.84; 95% confidence interval (CI) = 1.07-7.50; P = 0.036) and surgical site infection (adjusted OR = 3.53; 95% CI = 1.29-9.72; P = 0.014) in the all-cement spacer group. There was no difference in pathogen profile or the rate of positive intraoperative cultures during stage 2 (P = 1.000). 50% of patients of the six all-polyethylene tibial spacer group who did not undergo Stage 2 revision reported satisfaction with their spacer, whereas 50% of 10 non-revised patients in the cement spacer group underwent above-knee amputation (P = 0.158). This study found that the all-polyethylene spacer group had reduced rates of reoperation and infection as well as increased patient satisfaction in chronic PJI. While spacer designs showed viability for infection management, the all-polyethylene construct demonstrated favorable interim outcomes and may also have relevance as a retained spacer construct in selected patients.