Do Positive Cultures at Second Stage Re-Implantation Increase the Risk for Reinfection in Two-Stage Exchange for Periprosthetic Joint Infection?

• Published in: The Journal of arthroplasty Vol. 35; no. 10; pp. 2996 - 3001
• Main Authors: Theil, C., Freudenberg, Sophie C., Gosheger, G., Schmidt-Braekling, T., Schwarze, J., Moellenbeck, B.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-10-2020
• Subjects: Anti-Bacterial Agents - therapeutic use; Arthroplasty, Replacement, Hip - adverse effects; Arthroplasty, Replacement, Knee - adverse effects; Humans; periprosthetic joint infection; Prosthesis-Related Infections - epidemiology; Prosthesis-Related Infections - etiology; Prosthesis-Related Infections - surgery; Reinfection; Reoperation; Replantation - adverse effects; Retrospective Studies; revision arthroplasty; total hip arthroplasty; total knee arthroplasty; periprosthetic joint infection; total knee arthroplasty; total hip arthroplasty; revision arthroplasty
• ISSN: 0883-5403; 1532-8406
• DOI: 10.1016/j.arth.2020.05.029

Intraoperative cultures are important in the diagnosis and targeted treatment of periprosthetic joint infection (PJI). Positive cultures at reimplantation during a two-stage exchange are discussed as a risk factor for reinfection. The aim of this study is the investigation of the incidence and risk factors for positive cultures during reimplantation.
We retrospectively identified 204 patients (111 knees, 93 hips) who were treated between 2012 and 2016 for PJI using a two-stage exchange protocol at a median follow-up of 42 months. PJI was diagnosed using the criteria of the musculoskeletal infection society (MSIS) of 2011. All cultural findings from first and second stage surgery were recorded. The primary endpoint was revision for infection. Risk factors for positive cultures and reinfection were analyzed.
During reimplantation 25% (51/204) of patients had at least one positive culture, in 19.1% (39/204) only a single culture. Patients with culture-negative infections had a higher risk for positive cultures at reimplantation (HR 2.946 (95% CI 1.247-6.961), P = .014) and patients with infected total hip arthroplasty (THA) (HR 3.547 (95% CI 1.7-7.4), P = .001). Patients with positive cultures during reimplantation had a higher risk for reinfection (HR 2.27 (95% CI 1.181-4.363), P = .014) as well as patients with a single positive culture (HR 2.421 (95% CI 1.139-5.143), P = .021).
As positive cultures are common and increase reinfection risk irrespective of their numbers, longer antibiotic therapy following reimplantation can be an option. Single positive cultures in reimplantation surgery should not be considered contamination.