Gout in primary total knee arthroplasty: Prevalent but not independently associated with complications

Background: Gout is a common synovial pathology, but its prevalence in patients undergoing total knee arthroplasty (TKA) and potential association with complications such as periprosthetic infection (PJI) and revision are unknown. Methods: Medicare data from 2009 to 2013 was retrospectively reviewed using PearlDiver. All patients 65 years of age or older and undergoing primary TKA with at least 3 years of pre-TKA records were included. The prevalence of gout was based on ICD-9 codes. Univariable associations of gout with PJI and revision at 1 year were assessed using odds ratios with 95% confidence intrervals (C.I.). To control for potential confounding, patients with a history of gout were matched on age, gender, smoking history, and Elixhauser Comorbidity Index (ECI) to patients without gout and associations reassessed. Results: The prevalence of gout in Medicare patients undergoing primary TKA was 5.7%. On univariable analysis, patients with a history of gout were more likely to develop PJI (O.R., 1.58; 95% C.I., 1.45-1.72) and undergo revision (O.R., 1.33; 95% C.I., 1.25-1.41) at 1 year. After matching for confounders, a history of gout was no longer associated with developing PJI (O.R., 0.98; 95% C.I., 0.90-1.06) or undergoing revision (O.R., 0.94; 95% C.I., 0.89-1.00) at 1 year. Conclusions: Gout is a relatively common pathology in patients undergoing TKA. While gout is associated with increased complications, this appears to be driven by confounding through its association with other medical comorbidities. Gout does not appear to be an independent risk factor for complications following TKA. (C) 2020 Elsevier B.V. All rights reserved.