Repeat Two-Stage Exchange Arthroplasty for Recurrent Periprosthetic Knee Infection: Results of 87 Cases.

Background: Despite the success of two-stage exchange total knee arthroplasties (TKAs), a subset of patients become reinfected and may be considered for a repeat two-stage exchange TKAs. A small, prior study from our institution demonstrated a 50% re-revision rate in such a cohort. The purpose of the present study was to evaluate a contemporary and larger cohort of repeat two-stage exchange TKAs with an emphasis on implant survivorship, risk factors, and clinical outcomes.

Methods: We retrospectively identified 87 repeat two-stage exchange TKAs performed between 2014 and 2021. The mean patient age was 66 years, 32% were women, and the mean body mass index was 29. At the time of resection, 98% of patients were treated with a high-dose antibiotic spacer (58 nonarticulating and 27 articulating). The mean time from resection arthroplasty to reimplantation was 22 weeks. Kaplan-Meier survivorship analyses were performed, and risk factors (including the McPherson staging system) were assessed. The mean follow-up was five years (range, two to nine).

Results: The 5-year survivorships free of rerevision for reinfection, any rerevision, and any reoperation were 88, 67, and 54%, respectively. Leading causes for rerevision were periprosthetic joint infection (36%) and aseptic loosening (27%). There were no statistically significant independent risk factors identified. However, patients who had McPherson host grade C trended toward higher rates of reoperation (hazard ratio: 2, P = 0.057). Despite the high reoperation rate, at the final follow-up (mean five years), 91% of patients had a TKA in situ, 8% had been treated with above-knee amputation, and 1% with a definitive resection arthroplasty.

Conclusions: Despite its challenges, including a 54% reoperation rate, repeat two-stage exchange TKAs may be considered in a subset of patients given 91% of patients had a TKA in situ at a mean of five years, and the 5-year survivorship free of rerevision for infection was 88%. Notably, patients who were McPherson host grade C trended toward failure.

Level of evidence: Level IV.