Assessment of Musculoskeletal Infection Society (MSIS) Diagnostic Criteria as Predictors of Treatment Success in Hip Arthroplasty Infections Treated with Two-Stage Exchange

BACKGROUND: Prosthetic joint infection (PJI) is a grave complication of total hip arthroplasty (THA). Predicting outcome is difficult. Musculoskeletal Infection Society (MSIS) criteria are sensitive and specific for the diagnosis of PJI. In prior work, we systematically studied the value of each MSIS criterion as a prognostic marker among a large cohort of patients with infected hip and knee arthroplasty treated with debridement, antibiotics, and implant retention (DAIR) at our specialized orthopedic hospital. We found that sinus tract drainage and culture positivity predicted explantation within 2 years of DAIR; the minor MSIS criteria were not predictive. Here, we sought to evaluate the utility of MSIS criteria in predicting outcomes of infected THR PJI treated with two-stage exchange arthroplasty. We sought to evaluate whether MSIS criteria can predict outcome of infected THR PJI treated with two-stage exchange arthroplasty. METHODS: A retrospective cohort of PJI from 2007 to 2014 treated with two-stage exchange was identified via an administrative database. Two-year implant retention was the primary outcome. Collected data included demographics and comorbidities, duration of symptoms, implant age, and pathogen. Continuous variables were assessed using the Mann–Whitney U-tests and categorical variables using the χ (2) test and Fisher’s exact test when appropriate. RESULTS: One hundred and thirty patients who underwent two-stage exchange for THA PJI meeting MSIS criteria were identified. Ninety percent remained infection free after 2 years of observation. Neither of the major criteria [the presence of sinus drainage[(P = 0.5416), and >1 positive culture (P = 0.1052)], nor any of the minor criteria, reached statistically significant association with treatment outcome. CONCLUSION: Individual MSIS diagnostic criteria, which do have prognostic utility in hip and knee PJI treated with DAIR, may not be powerful predictors of outcome of hip PJI after two-stage exchange, likely in part because of the high success rate of this procedure. DISCLOSURES: All authors: No reported disclosures.