Emergency histological examination in diagnosis of periprosthetic joint infection in revision total knee arthroplasty

Introduction Diagnostic algorithms are used for detection of periprosthetic joint infection (PJI) including sampling for histological evaluation (HE). The purpose was to assess the diagnostic significance of emergency HE of fresh-frozen intraoperative biomaterial as part of preoperative PJI screening of patients undergoing revision total knee arthroplasty (RTKA). Material and methods The prospective study included 83 patients who were admitted to two trauma and orthopaedic centers for RTKA. The European Bone and Joint Infection Society 2021 (EBJIS21) algorithm was used to detect PJI of the knee joint. The diagnostic value of screening PJI with/without regard to the results of an emergency HE was compared with the results of a microbiological study (MBI) of all types of biomaterials obtained from each patient. Subanalysis was additionally performed in patients with aseptic instability and antimicrobial spacer. Results Pathomorphological examination of freshly frozen and paraffin-embedded tissues showed the difference of 7.2 %, which did not significantly affect the interpretation of the results (p > 0.05). Diagnostically significant pathogens were identified in 83.3 % of cases with PJI confirmed by emergency HE (p < 0.001). A positive emergency HE result increased the chances of isolating diagnostically significant organisms by 34 times (95 % confidence interval (CI): 4.721 – 244.859) as compared with negative HE cases. The proportion of detected cases with emergency HE included in the screening increased from 2.4 to 8.4 %. The inclusion of emergency HE in the screening improved the diagnostic value both in the general cohort of patients and in the subanalysis of comparison groups due to a two-fold increase in sensitivity. Conclusion Relevance of the emergency HE results and the PJI criteria should be considered as a significant prognostic factor for an infectious process, however, this technique should be used only in a complex algorithm for PJI detection. Poor outcomes in 18.2 % of cases of probable PJI necessitated a change in the approach to managing this cohort of patients.