Treatment Failure Rates Decrease Significantly at Approximately One Year Following Two-Stage Exchange Arthroplasty...

Area of Science:

• Orthopedic Surgery
• Infectious Diseases
• Biostatistics

Background:

• Two-stage exchange arthroplasty is a primary treatment for chronic periprostrosthetic joint infection (PJI).
• Optimal patient monitoring duration post-treatment remains an area needing further investigation.
• Understanding failure timepoints is critical for effective patient management and study design.

Purpose of the Study:

• To determine the ideal follow-up duration for patients undergoing two-stage exchange arthroplasty for PJI.
• To identify specific timepoints when the majority of treatment failures occur.

Main Methods:

• Retrospective analysis of 148 patients with chronic total knee arthroplasty (TKA) PJI treated between 2015-2022.
• Failure events were defined using the 2019 Musculoskeletal Infection Society Outcome Reporting Tool criteria.
• Bayesian regression and Monte Carlo Markov Chain simulations were employed to model cumulative failure curves and identify significant breakpoints.

Main Results:

• For Tier 1 failures (including suppressive antibiotics), a breakpoint was identified at 1.20 years, with significantly higher failure rates preceding this point.
• A two-breakpoint model revealed significant failure rate changes at 1.11 and 2.42 years.
• For Tier 1 plus 2 failures (excluding suppressive antibiotics), a breakpoint at 0.73 years indicated a substantially higher failure rate before this time.

Conclusions:

• Treatment failures for PJI following two-stage exchange arthroplasty tend to cluster early, particularly within the first year.
• While broad failure definitions show early clustering, reoperation failures may continue into the second year, necessitating extended monitoring.
• Identified breakpoints signify a decline in failure rates, not complete risk elimination, guiding optimal follow-up periods for research and clinical practice.