Suction drainage fluid culture during septic orthopaedic surgery, a retrospective study.

We evaluated the usefulness of suction drainage fluid culture after septic orthopaedic surgery to predict early surgical reintervention. We conducted a retrospective observational study, at the Groupe Hospitalier Paris Saint-Joseph between 2014 and 2019. All the patients undergoing septic orthopaedic surgery, with perioperative samples and a postoperative suction drainage device, were enrolled. We compared the group with positive or negative postoperative drainage fluid cultures, respectively, on surgical outcome. We included 246 patients. The drainage fluid culture was positive in 42.3% of the cases. Early surgical reintervention concerned 14.6% of the cases (n = 36), including 61.1% of patients with positive drainage fluid culture (n = 22/36). The risk factors associated with positive drainage fluid cultures were the debridement of the infected site (without orthopaedic device removal), an infection located at the spine, perioperative positive cultures to Staphylococcus aureus. The complete change of the orthopaedic device, and coagulase-negative staphylococci on the preoperative samples, was associated with negative drainage fluid cultures. Positive drainage fluid culture was predictive of early surgical reintervention, and coagulase-negative staphylococci in the preoperative samples and knee infection were predictive of surgical success. Postoperative drainage fluid cultures were predictive of early surgical reintervention. Randomized multicentric studies should be further conducted.