Exploring the Role of Sonication Fluid Culture in Orthopedic Implant-Related Infections: A Comparative Study with Conventional Methods

Murat Erem, Eşref Selçuk, Mert Özcan, Gözde Öztürk, Canan Eryıldız

Keywords: Orthopedic implant, infection, sonication fluid culture, conventional culture, diagnostic tool, sensitivity, specificity

Aim:

Orthopedic implant-associated infections present a significant challenge due to biofilm formation, necessitating effective detection methods. While traditional tissue and implant cultures are commonly used, the efficacy of sonication fluid culture (SFC) in identifying causative agents has been evaluated in numerous studies. In this study, the hypothesis is sonication provides more accurate results and allows for microorganism identification in more patients compared to the conventional methods of periprosthetic tissue culture and implant culture.

Method:

Three cultures were evaluated for diagnosing orthopedic implant-associated infections: intraoperative periprosthetic tissue culture, implant culture, and SFC. The sensitivity, specificity, and predictive values were calculated for each method, using the 2018 definition of periprosthetic hip and knee infection and clinical evaluation as references.

Results:

Of the 92 patients who had implants removed, 49 were for mechanical reasons and 43 for infection. Positive cultures were obtained in 13 out of 49 patients with mechanical issues and 31 out of 43 with infections. The sensitivity of periprosthetic tissue cultures (53.5%) is slightly higher than SFC (48.8%), suggesting better detection of positive cases. However, SFC's specificity (83.7%) is higher, indicating more accurate identification of negative cases compared to periprosthetic cultures (73.5%). However, SFC identified additional pathogens in patients with negative periprosthetic tissue and implant cultures. Examination of the infected knee and hip prostheses showed that SFC enhanced pathogen detection, particularly in patients with negative implant cultures. Despite this, SFC was not statistically superior to other methods.

Conclusions:

This study supports the combined use of periprosthetic tissue culture and SFC for identifying causative microorganisms in implant infections. Despite not being statistically superior, SFC provides additional pathogen detection, especially when other methods fail, thereby enhancing overall diagnostic accuracy.

#74