Periprosthetic joint infection (PJI) is among the most feared orthopedic complications. Critical questions are whether the infection is completely resolved before reimplantation and what the clinical significance of positive culture is at reimplantation. The aim of this study was to determine whether a correlation exits between culture results at reimplantation after spacer insertion for hip and knee PJI and treatment failure rate. The data of 84 patients who underwent two-stage exchange arthroplasty for hip or knee PJI were reviewed and the results of intraoperative culture at reimplantation were analyzed quantitatively and qualitatively. Correlations were sought between these patterns and treatment outcome. Our data indicate no evidence for a correlation between positive culture at reimplantation and greater risk of treatment failure. Nonetheless, we noted a higher, albeit statistically not significant rate of treatment failure in patients with at least two samples testing positive. The role of microbiology at reimplantation remains unclear, but a positive culture might signal increased risk for subsequent implant failure. Further studies are needed to elucidate the implications of this finding.

Osteomyelitis (OM) is a major challenge in orthopedic surgery. The diagnosis of OM is based on imaging and laboratory tests, but it still presents some limitations. Therefore, a deeper comprehension of the pathogenetic mechanisms could enhance diagnostic and treatment approaches. OM pathogenesis is based on an inflammatory response to pathogen infection, leading to bone loss. The present study aims to investigate the potential diagnostic role of a panel of osteoimmunological serum biomarkers in the clinical approach to OM. The focus is on the emerging infection biomarker sCD14-ST, along with osteoimmunological and inflammatory serum biomarkers, to define a comprehensive biomarker panel for a multifaced approach to OM. The results, to our knowledge, demonstrate for the first time the diagnostic and early prognostic role of sCD14-ST in OM patients, suggesting that this biomarker could address the limitations of current laboratory tests, such as traditional inflammatory markers, in diagnosing OM. In addition, the study highlights a relevant diagnostic role of SuPAR, the chemokine CCL2, the anti-inflammatory cytokine IL-10, the Wnt inhibitors DKK-1 and Sclerostin, and the RANKL/OPG ratio. Moreover, CCL2 and SuPAR also exhibited early prognostic value.

Background/Objectives: One-stage revision has become an increasingly accepted strategy for the treatment of chronic periprosthetic joint infection (PJI) of the knee in carefully selected patients. The use of a resorbable defensive antibacterial coating (DAC® hydrogel) represents an attractive adjunct to reduce bacterial adhesion and biofilm formation on revision implants. However, evidence regarding its long-term performance remains limited. Methods: We retrospectively reviewed 52 consecutive patients undergoing one-stage revision for knee PJI or infected spacer between 2014 and 2023 using a standardized surgical and antimicrobial protocol including local application of DAC hydrogel loaded with vancomycin alone or vancomycin plus meropenem. Clinical, microbiological and radiographic outcomes were evaluated. Infection-free survival was assessed using Kaplan–Meier analysis. Results: Forty-eight patients underwent revision for PJI and four for septic spacers. Four patients were unavailable for final evaluation. At mean follow-up of 7.0 ± 2.7 years (range 3–11 years), no infection recurrence was obtained in 47 of 48 clinically evaluable patients, corresponding to an infection-free survivorship of 97.9% at final follow-up. Mean Knee Society Score improved from 47.7 to 84.4 points, while functional KSS improved from 41.9 to 82.9 points. Pain at rest decreased from 6.9 to 0.7 and pain during movement from 8.1 to 1.6 on the visual analogue scale. Conclusions: This series represents, to our knowledge, the longest reported follow-up of one-stage knee revision using DAC antibacterial hydrogel. The favorable results obtained using hybrid fixation, with cemented epiphyseal fixation combined with uncemented stems coated with antibiotic-loaded DAC hydrogel, further expand the potential indications for this strategy. Larger comparative multicenter studies are warranted to confirm these findings.