Preoperative predictive values in patients operated with suspected septic arthritis: comparative analysis of diagnostic predictions in septic-aseptic arthritis differentiation

Objective: Septic arthritis is one of the orthopedic emergencies and involves a complex process in diagnosing and deciding on surgical drainage. In cases with a high suspicion of septic arthritis, surgical drainage is applied since septic arthritis cannot be ruled out. The aim of this study is to compare the preoperative predictive values of septic and aseptic arthritis groups in order to guide the confirmation of the diagnosis and decision-making for surgical drainage. Materials and Methods: A total of 103 knee septic arthritis cases operated with a preliminary diagnosis of septic arthritis between 2011-2022 were retrospectively examined. The demographic characteristics (age and gender), time of admission, complaints at admission (pain in the joint, increased heat, limited movement, swelling, redness, systemic fever), laboratory evaluation of joint fluid, and operation information of the cases included in the study were recorded. All findings were evaluated according to Newman's septic arthritis criteria, and patient groups were formed as septic-aseptic. Results: Of the 103 patients included in the study, 69 (67%) were evaluated as septic arthritis according to Newman criteria and retrospective follow-up, while 34 (33%) were evaluated as aseptic arthritis. The duration of symptoms-surgery was significantly lower in the septic group. Clinical examination findings and serum laboratory parameters were examined, and no significant difference was observed between the two groups. In our study, synovial glucose was calculated as a median value of 32 mg/dl in the septic group and 72 mg/dl in the aseptic group, with a p-value of 0.006. The ratio of synovial glucose to serum glucose at the time of admission was found to be 0.31 on average in the septic group and 0.75 in the aseptic group. Statistically, it was observed that it was significantly lower in the septic group compared to the aseptic group. Conclusion: Although the data in the literature are mostly sufficient to diagnose septic arthritis, the lack of clear diagnostic criteria supports a skeptical approach. Synovial glucose can be used as a predictive value in suspicious cases.