Obesity, co-morbidities and prior operations additively increase failure in 2- stage revision total knee arthroplasty for prosthetic joint infection.

Abstract Introduction Prosthetic joint infection (PJI) of the knee carries significant morbidity, mortality and economic cost. We hypothesise that obese and poor medical hosts will have a significant and additive increase in failure rate undergoing 2-stage revision total knee arthroplasty (TKA) for PJI. Methods All 2-stage revision TKA procedures for PJI performed at one institution were identified between 2005-2020. 144 patients were included and defined as success or failure based on published criteria regarding infection eradication, further intervention or mortality. The American Society of Anaesthesiologist (ASA) score and the Charlson Co-morbidity Index (CCI) were utilized to assess host grade. Patient, surgical, and microbiologic variables were investigated with univariable and multivariable analysis to explore association with risk of failure. Results In the cohort, 32.4% of patients failed with mean follow-up of 5.1 years. In multivariable analysis, the number of major operations requiring arthrotomy and implantation of new material between the primary and first stage, host grade and elevated body mass index (BMI) were the major contributors to failure. Combining these factors, with BMI>30 and 2 or more major operations, the failure rate increased to 76.5% and 71.4% respectively for ASA 3 (p= Conclusions In this cohort, multiple major operations between the primary and first stage, host grade and obesity were the major contributors to failure. When combining these factors, patients had an additive increase in failure rate. Treatments such as amputation or less invasive options and suppression should be discussed and considered in these patients.