Failure Rates After Treatment of Periprosthetic Joint Infection Using Musculoskeletal Infection Society Outcome...

Area of Science:

• Orthopedics
• Infectious Diseases
• Medical Outcomes Research

Background:

• Periprosthetic joint infection (PJI) treatment success rates vary due to inconsistent failure definitions.
• Existing consensus frameworks (MSIS ORT, Delphi) may not fully reflect clinically meaningful outcomes.
• This study compares PJI treatment failure rates using different definitions.

Purpose of the Study:

• To compare failure rates of PJI treatment using MSIS ORT, Delphi criteria, and a pragmatic clinical definition.
• To assess agreement between these outcome definitions at the patient level.
• To identify criteria causing disagreements between PJI outcome classifications.

Main Methods:

• Retrospective cohort study of 184 PJI episodes (hip and knee) with 12-month follow-up.
• Calculated failure rates using MSIS ORT, Delphi criteria, and a clinical definition.
• Assessed inter-definition agreement using cross-tabulations and reviewed discordant cases.

Main Results:

• Overall PJI treatment failure rates were 43.5% (MSIS ORT), 40.8% (Delphi), and 47.3% (clinical definition).
• High concordance between MSIS ORT and Delphi, but 12.5% of MSIS ORT successes were clinical failures.
• Failure rates varied between debridement, antibiotics, and implant retention (DAIR) and staged revision procedures.

Conclusions:

• PJI treatment failure is common irrespective of the outcome framework used.
• MSIS ORT and Delphi criteria provide similar aggregate failure rates but are not interchangeable with clinical definitions.
• The choice of outcome definition significantly impacts the interpretation of PJI treatment results.