Fungal periprosthetic joint infections (PJIs) are rare; however, they are of great clinical relevance because their diagnosis and treatment are highly challenging. The purpose of this study was to investigate the clinical outcomes of patients with fungal PJIs treated with two-stage exchange knee arthroplasty combined with prolonged antifungal therapy.
We reviewed our institutional joint arthroplasty database and identified 41 patients who were diagnosed with fungal PJIs and treated with two-stage exchange arthroplasty after primary total knee arthroplasty (TKA) between January 2001 and December 2020 at our center. These patients were compared with patients who had non-fungal PJIs during the same period. After propensity score matching based on age, sex, body mass index, American Society of Anesthesiologists (ASA) grade, and Charlson Comorbidity Index (CCI), 40 patients in each group were successfully matched. The surgical and antimicrobial treatment, patient demographic and clinical data, re-infections, survival rates, and relevant risk factors that affected joint survivorship were analyzed. We defined treatment success as a well-functioning arthroplasty without any signs of a PJI and without antimicrobial suppression after a minimum follow-up from the time of reimplantation of two years.
The fungal PJI group demonstrated a significantly worse treatment success rate at the final follow-up than the non-fungal PJI group (65.0% versus 85.0%; p < 0.001). The mean prosthesis-free interval was longer in the fungal PJI group than in the non-fungal PJI group (6.7 weeks versus 4.1 weeks; p = 0.020). The rate of survivorship free from reinfection was worse in the fungal PJI group (83.4% at 1 year and 76.4% at 2 years) than in the non-fungal PJI group (97.4% at 1 year and 90.3% at 2 years), but the differences were not significant (p = 0.270; log-rank test). Cox proportional hazard regression analysis identified the duration of the prosthesis-free interval as a potential risk factor for failure (HR = 1.128, p = 0.043).
Fungal PJIs had a lower treatment success rate than non-fungal PJIs despite two-stage revision arthroplasty and appropriate antifungal treatment. Our findings highlight the need to develop novel treatments for fungal PJIs that more completely eradiate these infections.