Objective:To investigate the relevant factors on serum C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) which did not meet the 2011 Musculoskeletal Infection Society (MSIS) diagnostic criteria in patients with periprosthetic joint infection (PJI).Methods:During December 2011 to December 2019, a total of 328 patients with PJI were hospitalized for surgery or antibiotic administration, including 152 males and 166 females, aged 62.10±13.74 (range 24-87) years. All patients underwent CRP and ESR before the antibiotic administration or the revision surgery. PJI was diagnosed based on the 2011 MSIS diagnostic criteria. There were 172 knee PJIs (52.4%), 151 hip PJIs (46.0%), 4 elbow PJIs (1.2%) and 1 shoulder PJI (0.3%). Patients were classified according to Tsukayama type, pathogen and immune status. We, further, analyzed relevant factors on CRP and ESR levels in PJI patients.Results:There were 119 patients with CRP and ESR did not meet the MSIS diagnostic criteria, accounting for 36.3% (119/328). Furthermore, there was no significant difference in Tsukayama types among them (χ 2=7.224, P=0.065). In addition, the ratio was 46.4% in patients with negative culture results, which was higher than that in positive culture results (27.4%, χ 2=12.276, P<0.001). The ratio was 42.9% in patients with normal immune status (grade A), which was higher than that of immune grade B (30.6%) and of immune grade C (23.8%) (χ 2=6.586, P=0.037). Multivariate logistic regression analysis showed the negative association between positive culture results and immune grade B with nonconformity ( OR=0.420, P=0.001; OR=0.578, P=0.04). Conclusion:The serum tests level unmet the threshold in MSIS criteria usually present in PJI patients with normal immune status and negative culture results. Thus, we should utilize other methods for diagnosing PJI.

Arthroplasty, Replacement, Knee ; Humans ; Knee Joint/surgery* ; Leg ; Lower Extremity/diagnostic imaging* ; Osteoarthritis, Knee/surgery* ; Rotation ; Tibia/surgery*

Objective:To investigate the clinical characteristics and risk factors for patients with chronic periprosthetic joint infection (PJI) combined with sinus tract.Methods:The patients with PJI following hip and knee arthroplasty from July 2014 to January 2020 in our institution were retrospectively reviewed. There were 96 males and 101 females, aged from 26 to 86 years with mean age of 62.02±13.54 years. There were 95 hip PJI patients (48.2%, 95/197), 102 knee PJI patients (51.8%, 102/197), 68 patients (34.5%, 68/197) with sinus tract, 129 patients (65.5%, 129/197) without sinus tract, 162 patients (82.2%, 162/197) with positive culture results and 35 patients (17.8%, 35/197) with negative culture results. The patients were divided into two groups according to the sinus tract formation. The diagnosis of PJI was based on the 2011 Musculoskeletal Infection Society (MSIS) criteria. All of the included patients underwent serological laboratory tests (white blood cell count, neutrophil percentage, lymphocyte percentage, hemoglobin, platelet count, mean platelet volume, urea, creatinine, albumin, erythrocyte sedimentation rate, C-reactive protein) and pathogen isolation. The influence of sinus tract on the above test and the effects of complications on sinus tract formation were analyzed. We further investigated the relationship between sinus tract formation and the features of pathogen. In addition, the risk factors for sinus tract formation were analyzed.Results:The mean values of all serological tests were without statistical difference between the groups with and without sinus tract ( P>0.05). The presence of complications had no effect on the occurrence of sinus tract ( P>0.05). The incidence of sinus tract with highly virulent pathogen infection group (52.1%, 25/48) was significantly higher than that in low virulence pathogen group (27.5%, 19/69), in culture negative patients (40.0%, 14/35) and in other cases (22.2%, 10/45; χ 2=11.519, P=0.009). There was no statistical difference between groups based on the Gram staining, antibiotic resistance and polymicrobial infection. Multivariate logistic regression analysis revealed positive associations of extra joint infections ( OR=4.426, 95% CI: 1.095, 17.884) and high virulent pathogen infections ( OR=2.633, 95% CI: 1.171, 5.918) and negative association of age ≥70 ( OR=0.436, 95% CI: 0.205, 0.927) with the risk of sinus tract formation. Conclusion:The presence of sinus tract has no effect on the routine serum tests in patients with chronic PJI. There is only virulence factor which might affect sinus tract formation. For patients with the extra joint infections and high virulence pathogen infections, the formation of sinus tract should be vigilant during treatment.