Survival and Outcomes of 1.5-Stage vs 2-Stage Exchange Total Knee Arthroplasty Following Prosthetic Joint Infection.

Background: Traditional management of prosthetic joint infection following total knee arthroplasty (TKA) consists of a 2-stage approach. However, 1.5-stage exchange has seen preliminary success, whereby metal femoral and all-polyethylene tibia components are placed without intention for subsequent second stage. We sought to examine all patients who underwent a 1.5-stage exchange TKA at a single institution compared to historical 2-stage controls. We assessed the following: (1) infection-free survivorship and risk factors for reinfection; (2) 1-year surgical/medical outcomes; (3) patient-reported outcomes (ie, Knee Injury and Osteoarthritis Outcome Score for Joint Replacement [KOOS JR]); and (4) radiographic outcomes.

Methods: We reviewed all patients undergoing a 1.5-stage (between 2015 and 2019) and 2-stage exchange TKA (between 2011 and 2016) at a single institution. A total of 162 knees were included (1.5-stage: 114; 2-stage: 48) with mean clinical follow-up of 2.6 years. KOOS JR scores and radiographic outcomes were evaluated at last clinical follow-up.

Results: The 1.5-stage exchange TKA resulted in a 10.1% difference in infection-free survival (85.1% vs 75.0%, P = .158), compared to 2-stage exchange. Prior prosthetic joint infection was found to be an independent risk factor for reinfection (P = .030). Overall, postoperative complications were lower among 1.5-stage exchanges (8.8% vs 31.3%, P < .001). KOOS JR scores improved more from baseline among 1.5-staged (Δ24.7 vs Δ16.6, P < .001). Radiographic review did not demonstrate any progressive radiolucent lines, subsidences, or failures in either group.

Conclusion: A 1.5-stage exchange TKA is an effective alternative to the traditional 2-stage protocols with noninferior infection eradication and absence of radiographic complications at over 2 years of mean follow-up.