Background: Diagnosis of periprosthetic joint infection (PJI), especially chronic PJI, is very confusing and challenging. The value of C-reactive protein (CRP) in infectious diseases has been recognized, but the diagnostic value of CRP in chronic PJI is unknown. Our aim was to investigate the diagnostic value of synovial CRP in chronic PJI and to explore the role of combined serum and synovial CRP in distinguishing chronic PJI from aseptic failure after knee and hip arthroplasties. Methods: We prospectively enrolled patients scheduled to have a revision surgery for chronic PJI or aseptic loosening from January 2019 to December 2020, in which synovial CRP was additionally measured along with routine preoperative diagnostic serum ((ESR, CRP) and synovial (PMN%) biomarkers. The receiver operating characteristic (ROC) curves and area under the curve (AUC) were analyzed for each biomarker to determine diagnostic efficacy. Results: There were no statistically significant differences between the infection (n = 39) and aseptic (n = 58) groups, including 61 hips and 36 knees. The synovial CRP levels were significantly higher in the infection group than in the aseptic group (median: 9.93 mg/l vs 3.58 mg/l; p < .001). The optimal cut-off value for detecting chronic PJI of Synovial fluid (SF) CRP was of 7.26 mg/l with a sensitivity of 84.62%, a specificity of 93.10%. The combined model I (Serum CRP > 10.2 mg/l OR SF CRP > 7.26 mg/l) had a negative predictive value (NPV) of 96.67%, and a sensitivity of 97.44%. The combined model II (Serum CRP > 10.2 mg/l AND Synovial CRP > 7.26 mg/l) led to a specificity of 1, and a positive predictive value (PPV) of 1. Conclusions: The present study demonstrated that the combination of serum and synovial CRP can be used as an adjunct to the diagnosis of chronic PJI.

Preoperative diagnosis of periprosthetic joint infection (PJI) is critical to guide treatment options and improve patient outcomes. In this letter, the authors discuss results from our experiences with a novel nomogram diagnosis model based on serum and synovial fluid indicators for the preoperative diagnosis of PJI. The results showed that the novel nomogram diagnosis model can distinguish PJI from aseptic loosening before the operation. And it is also a useful candidate for the selection of the timing of current secondary revision.

Infected wounds pose a significant clinical challenge, as persistent bacterial colonization exacerbates inflammation, disrupts the local immune microenvironment, and delays tissue repair. Here, we report the development of a 3D printing dual-crosslinked hydrogel scaffold loaded with ginger-derived exosome-like vesicles (GPP@G-ELNs) to promote healing of infected full-thickness wounds. The hydrogel was fabricated by combining GelMA-PBA and PVA to form a dual-network structure, followed by photo-crosslinking and 3D printing, and then loaded with G-ELNs. The bioactivity of the scaffold was evaluated in an infected rat wound model, focusing on wound closure, angiogenesis, antibacterial efficacy, and immunomodulatory effects. Treatment with GPP@G-ELNs hydrogel significantly accelerated wound healing, reduced inflammatory cell infiltration, promoted collagen deposition, and enhanced angiogenesis. Moreover, the hydrogel exhibited potent antibacterial activity, with ginger-derived exosomes playing a critical role in modulating macrophage polarization and controlling local immune responses. These findings demonstrate that the 3D printing GPP@G-ELNs hydrogel provides an integrated platform for infection control, immunoregulation, and tissue regeneration, offering promising potential for clinical application in the management of infected wounds.

Background: The reactive enlargement of external iliac lymph nodes and increased blood flow in the infected region are commonly observed in lower limb infections. We aimed to differentiate between aseptic loosening and periprosthetic joint infection (PJI) after joint replacement surgery by quantifying the number of enlarged external iliac lymph nodes and using bone scintigraphy to monitor blood flow. Methods: We recruited 124 patients undergoing revision surgery for aseptic loosening or PJI. All the patients underwent preoperative dual-energy computed tomography (DECT) imaging for external iliac lymph nodes and bone scintigraphy. The diagnostic value was evaluated using ROC curve analysis. Results: The number of enlarged external iliac lymph nodes was significantly higher in the PJI group than in the aseptic failure group (4.0 versus. 1.0, p value < 0.001). The median affected/unaffected side ratio in the blood pool phase of ECT in the PJI group was 1.49, significantly higher than the aseptic failure group’s median ratio of 1.04 (p value < 0.001). The AUC for diagnosing PJI using the number of enlarged lymph nodes alone was 0.91, and when using the bone scintigraphy blood pool phase alone, the AUC was 0.89. When both metrics were combined, the AUC increased to 0.95, which was higher than the AUCs for the ESR (AUC = 0.83), CRP (AUC = 0.76), and synovial fluid PMN% (AUC = 0.62). Conclusions: Combining the enlargement of the lymph node count with the bone scintigraphy blood pool phase is a promising approach for diagnosing PJI.