Facility Cost Differences Between Single-stage and Two-stage Exchange for Chronic Periprosthetic Joint Infection: A Time-driven Activity-based Costing Analysis

BACKGROUND: With increasing data supporting the use of single-stage exchange over two-stage exchange for select patients with periprosthetic joint infection (PJI) after total hip arthroplasty (THA) and total knee arthroplasty (TKA), it is important to specifically quantify cost differences between the two procedures. This study aimed to compare itemized facility costs of single-stage and two-stage exchange. METHODS: This retrospective cohort study identified 118 consecutive patients who were diagnosed with chronic PJI and underwent revision THA or TKA at a single high-volume academic institution. Of 63 hip PJI patients (53.4%), 38 (60.3%) underwent single-stage revision and 25 (39.7%) underwent two-stage revision. From 55 knee PJI patients (46.6%), 19 (34.5%) underwent single-stage revision and 36 (65.5%) underwent two-stage exchange. Patients were excluded if they had soft-tissue coverage requirements or extensive bone loss requiring endoprosthesis. Facility costs were calculated using time-driven activity-based costing methodology. Costs were combined for the two hospital admissions for a two-stage exchange. RESULTS: Patients undergoing single-stage revision TKA had lower personnel ($46,397 vs. $78,765, P < 0.001), implant ($19,822 vs. $85,605, P < 0.001), and overall costs ($79,548 vs. $171,592, P < 0.001) when compared with two-stage revision. Similarly, patients undergoing single-stage revision THA had lower personnel ($46,718 vs. 99,255, P < 0.001), implant ($19,936 vs. 73,372, P < 0.001), and overall costs ($79,349 vs. 187,251, P < 0.001) than two-staged procedures. Implant costs demonstrated the highest variation between two-stage and one-stage revisions for TKA (4.3 times) and THA (3.7 times). Total surgical time was significantly longer in two-staged THA (365 vs. 175 minutes, P < 0.001) and TKA (256 vs. 162 minutes, P < 0.001) revisions. CONCLUSION: Single-staged revisions cost markedly less than two-staged procedures for first-time, chronic PJI when using strict surgical indications. Given the growing emphasis on value-based care, if single-stage arthroplasty is at least as effective as two-stage exchange in some PJI settings, the cost savings of this procedure would be tremendous. LEVEL OF EVIDENCE: Level III.