Dynamics of Synovial Fluid Markers Following Single-Stage Exchange and Debridement, Antibiotics, and Implant Retention Procedure with Topical Antibiotic Infusion in Treating Periprosthetic Joint Infection.

Introduction: Periprosthetic joint infection (PJI) is a severe complication following total joint arthroplasty (TJA). This study aimed to investigate the dynamics of synovial fluid markers following single-stage exchange arthroplasty or debridement combined with antibiotics and implant retention (DAIR) with topical antibiotic infusion for PJI.

Methods: This retrospective study analyzed patient records at a tertiary hospital from March 1, 2018, to May 1, 2023. Patients who received single-stage exchange arthroplasty or DAIR followed by intra-articular antibiotic infusion for PJI were included. Basic demographic details, comorbidities, Charlson Comorbidity Index (CCI) scores, microorganism profile, presence of sinus tract, and antibiotic treatment type were collected. Synovial fluid samples were collected preoperatively and postoperatively every two days for 14 days to quantify synovial white blood cell (WBC) count and polymorphonuclear cell percentage (PMN%).

Results: The study included 140 patients who had a mean age of 63 years and a mean body mass index (BMI) of 25. The results showed a steady decrease in synovial WBC count from preoperative levels to Day 14 postoperative. Patients who had successful outcomes had significantly higher preoperative WBC counts compared to those who had a treatment failure. The synovial PMN% initially increased postoperatively, peaking at days one to two, and then gradually declined. Patients who had successful outcomes showed a faster decline in PMN% compared to those who had persistent infections. Different bacteria exhibited varying preoperative synovial WBC counts and PMN%, but these differences were not statistically significant.

Conclusion: Monitoring synovial WBC count and PMN% can help distinguish between normal postoperative inflammation and persistent infection. Higher preoperative synovial WBC counts are associated with successful outcomes, suggesting their potential role in predicting treatment success. Future research with larger sample sizes is necessary to further validate these findings and improve the management and diagnosis of PJI.