Factors Associated With the Incidence and Timing of Total Knee Arthroplasty Infection.

ABSTRACT

BACKGROUND: Periprosthetic joint infection (PJI) following total knee arthroplasty remains a challenging clinical problem. This study examined variables related to the incidence and timing of PJI. METHODS: We retrospectively reviewed 8462 primary total knee arthroplasties performed at our institution between 2006 and 2018 for PJI. The mean follow-up is 3.7 years. Eighty-seven variables including patient-reported diagnoses, demographics, and medications were collected. Time to infection, bacterial organism, success of infection treatment, and variables associated with infection are reported. RESULTS: PJI occurred in 105 (1.24%) cases. The incidence of infection in the first year was 0.72% and represented 58% of all infections. Multivariate Cox regression revealed males (hazard ratio [HR] = 2.85, 95% confidence interval [CI], 1.69-4.79) and patients with major depression or anxiety (HR = 2.11, 95% CI, 1.21-3.67) were more likely to develop an infection in the first year. After the first year, patients with a history of cellulitis (HR = 3.97, 95% CI, 1.91-8.27) and those taking antiepileptic medications (HR = 3.61, 95% CI, 1.73-7.52) were more likely to develop an infection. Culture-negative infections were more common after one year than before (23% vs 8%, P = .04). Debridement, antibiotics, and implant retention was used in 79% (48/61) of infections in the first year and 55% (24/44) after one year with success rates of 51% and 70%, respectively (P = .16). CONCLUSION: The majority of infections occur during the first year after surgery. Importantly, patient variables associated with infection are different among infections that occur before and after one year. A multicenter study with a much larger number of infections may allow analysis of more time intervals after surgery.