Predictors of Recurrent Infection and Failure of 2-Staged Treatment of the Infected Total Knee Arthroplasty

Multiple reports highlight midterm success of eradicating periprosthetic TKA infection via the 2-stage approach and others identify risk factors for surgical site infection (SSI) following TKA. Factors predicting failure of 2-stage TKA infection treatment protocol TKA are unknown. The purpose of this study is to determine if known risks factors for primary TKA SSI are risk factors for failure of 2-stage infection treatment. Retrospective review revealed 90 reimplantation TKA (87 patients) performed using a single modular revision device by a single surgeon. Cases with other devices were excluded. Demographic variables and medical comorbidities were identified. Statistical analysis included Log-Rank/Wilcoxon tests for predictors of failure (95% CI, Power 80%). Followup averaged 46 months, 60 months in 47 living patients, and 30 months in 40 deceased patients. Age averaged 70 years. Height, weight, and BMI averaged 67 inches, 206 lbs, and 32.8. Thirteen knees (14.4%) experienced recurrent infection, for a survival free-of-infection of 85.5% at up to 14 years. No medical comorbidites were associated with an increased risk of failure: diabetes (p = 0.8), rheumatoid (p = 0.3), infection elsewhere (p = 0.3) age >70 years (p = 0.2), obesity (p = 0.3), renal failure (p = 0.6), COPD (p = 0.7), and cancer (p = 0.8). Postoperative drainage or wound complication requiring incision and drainage (I&D), was associated with subsequent septic failure (p = 0.01). Ten knees required I&D and 4 of these failed due to sepsis. Medical comorbidities associated with SSI in TKA are not significant risk factors for 2-stage/reimplantation treatment of infection failure. Wound complication or drainage requiring I&D is a risk factor for failure. Prevention of drainage should be explored for these patients, such as limiting anticoagulation.