Culture Negative Prosthetic Joint Infectionandndash;A Description of Current Treatment and Outcomes.

Background: The management of prosthetic joint infections remains a clinical challenge particularly when standard aerobic and anaerobic culture techniques fail to isolate the causative pathogen, so called ‘culture negative prosthetic joint infection’ (CNPJI). There are few studies detailing approaches to management in this cohort of patients. This study reports the treatment and outcomes of 19 patients with CNPJI. Results: The majority of patients (68%) with CNPJI had exposure to antibiotic therapy in the week prior to presentation with CNPJI. Patients with early (10 patients) and haematogenous (3 patients) CNPJI were treated with debridement and retention of the prosthesis. In contrast, patients with delayed and late chronic CNPJI (6 patients) were managed by two-stage exchange. In addition to the surgical management patients were commenced on broadspectrum oral antibiotics combination therapy with rifampicin, fusidic acid +/- ciprofloxacin for a prolonged duration (median 7 months; interquartile range 3-20). Patients were followed up for a median of 19 months (interquartile range 13-29). Two patients experienced treatment failure with a 12 month estimate of infection free survival of 95% (95% confidence interval: 68,99). Of concern, 28% patients receiving oral antibiotics experienced adverse effects necessitating change in treatment. Conclusions: In this cohort, the outcomes for patients with CNPJI were comparable to those reported for culture positive infections, and contrary to previous recommendations, this study demonstrates that debridement and retention of a CNPJI is reasonable for patients with early infections. It also highlights the importance of exclusion of prosthetic joint infection prior to instigation of antibiotic therapy to optimise peri-prosthetic tissue culture yields to avoid this situation in which multiple broad spectrum antibiotics with potential side effects become necessary