Objective:To investigate the values of combined detection of serum C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), platelet count (PC), platelet count/mean platelet volume (PC/MPV) and platelet plateletcrit (PCT) in the diagnosis of chronic periprosthetic joint infection (PJI).Methods:From January 2013 to December 2019, 441 patients underwent hip or knee joint revision at Department of Articular Surgery, The First Hospital Affiliated to Xinjiang Medical University. The patients were divided into a chronic PJI group and an aseptic prosthetic loosening group. In the chronic PJI group of 147 cases (86 hip ones and 61 knee ones), there were 64 males and 83 females, with a mean age of 66 (54, 72) years. In the aseptic prosthetic loosening group of 294 cases (210 hip ones and 84 knee ones), there were 98 males and 196 females, with a mean age of 63 (49, 72) years. The preoperative levels of CRP, ESR, PC, PC/MPV and PCT were compared between the 2 groups. The best cut-off value, sensitivity and specificity of the above indicators for the diagnosis of chronic PJI were recorded. The diagnostic efficacy of the 5 indicators in combination for chronic PJI was evaluated by comparing the area under the curve (AUC) among the indicators and analyzing the results of combined diagnostic detections.Results:Except for gender and joint revision site, there was no significant difference in the other general data between the 2 groups, showing comparability ( P>0.05). The levels of CRP, ESR, PC, PC/MPV and PCT in the PJI group were significantly higher than those in the aseptic prosthetic loosening group ( P<0.05). For CRP, ESR, PC, PC/MPV and PCT, respectively, the best cut-off values were 9.05 mg/L, 38.5 mm/h, 288×10 9/L, 29.34 and 0.33%, the sensitivities 83%, 71%, 44%, 44% and 33%, the specificities 85%, 86%, 84%, 84% and 90%, and the AUCs 0.868, 0.822, 0.688, 0.696 and 0.659. For CRP+ESR+PC+PC/MPV+PCT and CRP+PC+PC/MPV+PCT, respectively, the AUCs were 0.871 and 0.882, the sensitivities 80% and 84%, and the specificities 86% and 84%, showing significant differences in the diagnosis of chronic PJI compared with ESR, PC, PC/MPV and PCT alone ( P<0.05). Conclusion:In the diagnosis of chronic PJI, serum CRP and ESR combined with PC, PC/MPV and PCT have a reference value, but PC, PC/MPV or PCT alone only has a limited value.

Objective:To investigate the gender differences in serum C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), platelet (PLT), fibrinogen (FIB) and D-dimer for the diagnosis of chronic periprosthetic joint infection (PJI).Methods:A total of 470 patients who underwent revision arthroplasty in the Department of Joint Surgery, First Affiliated Hospital of Xinjiang Medical University from January 2013 to December 2021 were retrospectively analyzed. According to gender and diagnosis, they were divided into four groups: 78 cases of male chronic PJI, 108 cases of male aseptic loosening, 95 cases of female chronic PJI, and 189 cases of female aseptic loosening. The serological results of CRP, ESR, PLT, FIB and D-dimer were collected before operation. The receiver operating characteristics (ROC) curves were used to determine the optimal cut-off values of CRP, ESR, PLT, FIB and D-dimer for the diagnosis of chronic PJI in different genders, and to calculate their sensitivity and specificity. The diagnostic efficacy of the index was analyzed by comparing the area under curve (AUC) of different indicators.Results:The levels of ESR, PLT and D-dimer in the male chronic PJI group were 43 (20.0, 52.5) mm/1 h, 249×10 9 (204×10 9, 306×10 9) /L, 449 (219,833) μg/L, respectively, which were lower than those in the female group of 56 (40, 65) mm/1 h, 295×10 9 (228×10 9, 364×10 9) /L, and 645 (345, 1 157) μg/L, with statistically significant differences ( Z=-4.17, P<0.001; Z=-2.17, P=0.030; Z=-2.82, P=0.005). The AUC of CRP in the male chronic PJI group was 0.841, which was higher than the AUC of the other four indicators; CRP was combined with ESR, PLT, FIB and D-dimer to establish a joint prediction model for male chronic PJI. The ROC curve showed that the combination of CRP+FIB had a maximum AUC [0.849, 95% CI (0.79, 0.91)], sensitivity of 80% and specificity of 86%. The AUC of CRP in the female chronic PJI group was 0.866, which was higher than the AUC of the other four indices; CRP was combined with ESR, PLT, FIB and D-dimer to establish a combined prediction model for female chronic PJI. The ROC curve showed that the combination of CRP+PLT had the maximum AUC [0.883, 95% CI (0.84, 0.93)], sensitivity of 87% and specificity of 79%. Conclusion:Serologic indicators in patients with chronic PJI are gender-specific. CRP combined with FIB has the highest diagnostic value for the chronic PJI in males, while CRP combined with PLT has the highest diagnostic value for the chronic PJI in females.

Objective:To investigate the diagnostic value of plasma fibrinogen (FIB) in chronic periprosthetic joint infection (PJI).Methods:A total of 470 patients who underwent revision hip and knee arthroplasty after primary hip and knee arthroplasty in the First Affiliated Hospital of Xinjiang Medical University from January 2013 to December 2021 were retrospectively analyzed. According to the diagnosis of the disease, 173 patients (112 hips and 61 knees) were divided into chronic PJI group, including 78 males and 96 females, aged 65 (53, 72) years; and 297 patients (216 hips and 81 knees) were divided into aseptic loosening group, including 108 males and 189 females, aged 63 (50, 72) years. The preoperative levels of FIB, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), D-dimer and platelet were compared between the two groups, and the sensitivity and specificity of the diagnosis of chronic PJI were calculated. Receiver operating characteristic (ROC) curves were used to determine the optimal cut-off values of FIB, CRP, ESR, platelet and D-dimer for the diagnosis of chronic PJI. The diagnostic efficacy of each indicator was analyzed by comparing the area under curve (AUC) and using a combined diagnostic test.Results:FIB, CRP, ESR, platelets and D-dimer in the chronic PJI group were 4.05 (3.52, 4.72) g/L, 19.5 (10.7, 40.0) mg/L, 50 (28, 60) mm/1 h, 270 (221, 351)×10 9 /L, 514 (261, 873) μg/L, respectively, which were higher than 3.25 (2.80, 3.63) g/L, 3.7 (2.0, 6.7) mg/L, 20 (12, 30) mm/1 h, 225 (182, 269)×10 9 /L, and 310 (167, 569) μg/L in sterile loosening group, with statistically significant differences ( P<0.05). The AUC of FIB, CRP, ESR, platelets and D-dimer in the diagnosis of chronic PJI were 0.78 (95% CI: 0.73, 0.82), 0.86 (95% CI: 0.82, 0.89), 0.80 (95% CI: 0.76, 0.85), 0.68 (95% CI: 0.63, 0.73), 0.64 (95% CI: 0.59, 0.69); the optimal cut-off values were 3.73 g/L, 9.64 mg/L, 39 mm/1 h, 280×10 9 /L, 624 μg/L; the sensitivity was 68%, 79%, 69%, 47%, 43%; the specificity was 81%, 85%, 85%, 81%, 79%, respectively. When CRP, ESR, FIB, platelets and D-dimer were combined sequentially to diagnose patients with chronic PJI, the sensitivity and specificity of the series test were 12.7% and 99.7%, and those of the parallel test were 100% and 37.3%. The combined diagnostic test showed that the maximum AUC of FIB combined with CRP was 0.85 (95% CI: 0.81, 0.89), with a sensitivity of 76% and a specificity of 89%. Conclusion:The clinical value of plasma FIB in the diagnosis of chronic PJI is not superior to that of CRP and ESR, but the combination of FIB and CRP can improve the specificity.