The study aimed to investigate the dynamic changes of percutaneous partial oxygen pressure during the development and evolution of a hypertrophic scar. Twenty cases of hypertrophic scar patients at different stages were selected. A percutaneous oxygen monitor was used to measure oxygen partial pressure in the scar and normal skin tissue at 14, 30, 60, and 90 days after surgery. The changes of oxygen partial pressure, tissue structure, HIF-1α, and VEGF expression in the scar tissue were observed, and the correlation was analyzed. In the scar maturation process, with the prolongation of time, the partial oxygen pressure in the tissue increased gradually. The expression intensity of HIF-1α and VEGF decreased gradually, HIF-1α was positively correlated with VEGF (r = 0.98, P < 0.01 ), there was a negative correlation between oxygen partial pressure and HIF-1 α expression (r = −0.92, P < 0.01 ), and it was negatively correlated with VEGF (r = −0.88, P < 0.01 ). TcPO2 measurement can be used to assess scar maturity; HIF-1 α and VEGF may play an essential role in regulating partial oxygen pressure in the scar tissue.

Background: The study aims to use five common pathogenic bacteria in Fracture-related infection (FRI) to establish a simple and fast multiplex qPCR method for initially clinical FRI detection. Methods: A total of 66 patients with FRI and 24 noninfectious volunteers were enrolled. Results from tissue culture and multiplex qPCR were analyzed and compared. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), Youden Index and area under the ROC curve (AUC) of the two methods were calculated respectively. Results: For 66 FRI cases, tissue culture detected 63 cases (95.5%) and multiplex qPCR detected 56 cases (84.8%). Among the 24 control cases, 12.5% and 16.7% were detected positive by tissue culture and multiplex qPCR, respectively. The sensitivity and specificity of multiplex qPCR were 84.8% and 66.7%, while those of tissue culture were 95.4% and 87.5%, respectively. To 51 cases within the detection profile, five common pathogens of FRI, the sensitivity and specificity of PCR changed to 92.2% and 90.9%, respectively. Conclusion: The advantage of multiplex qPCR is short processing time (< 5h) and simple steps. The multiplex qPCR may provide a complemental method for clinical FRI detection due to the simplicity and rapidity.

Objectives: This study compared the results of bacterial culture from operation versus sinus tract samples in patients with fracturerelated infection (FRI), and examined the ability of bacterial culture in sinus tract to identify pathogenic bacteria. Methods: A retrospective analysis of 53 patients with FRI from June 2016 to June 2021 was done. Common infection sites were femur, tibiofibular, hip joint, and ankle. Samples collected in sinus tract and during the operation were sent for bacterial culture. Results were summarized and compared, respectively, with pathogenic bacteria. Results: In sinus tract bacterial culture, bacteria were found in 75.6% of culture samples. The top 3 bacteria presented were: Staphylococcus aureus (32.26%), Staphylococcus epidermis (12.90%), and Pseudomonas aeruginosa (8.06%). Bacterial culture from the sinus tract matched the result of intraoperative samples 67.30% of the time, while 51.50% matched the pathogenic bacteria. Conclusion: Bacterial culture of sinus tract samples is not recommended as the basis for identifying pathogenic bacteria. Stopping antibiotic 2 weeks before operation, taking multiple samples at different sites, and sending multiple samples for bacterial culture are good ways to improve pathogen detection rate.

Background: This study summarizes the clinical features of bacterial cultures collected from infection after fracture fixation (IAFF), compares the results of bacterial culture from debridement versus sinus tract samples, and examines the relationship between the number of culture samples and success in identifying pathogenic bacteria. Methods: A retrospective analysis of 255 patients (202 males and 53 females) with IAFF from August 2017 to April 2020 was done. Common infection sites were femur, tibiofibular, hip joint, ankle, and humerus. Debridement was performed 438 times. Samples collected during debridement were sent for bacterial culture 295 times, with a variable number of culture samples taken. All samples were sent for general bacterial culture; results were summarized and success identifying pathogenic bacteria was compared for different culture sample sizes. Results from sinus tract samples (n=57) were also compared with pathogenic bacteria found in debridement samples. Results: In patients with IAFF, debridement samples had more gram-positive than gram-negative bacteria; the top 5 bacteria presented were: Staphylococcus aureus, Staphylococcus epidermis, Pseudomonas aeruginosa, Enterobacter cloacae, and Escherichia coli. Bacteria were found in 75.6% of culture samples from debridement. Five samples showed the highest rate of detection (90.6%) and 82.8% were identified with pathogenic bacteria. The cultural results from the sinus tract matched with those from the debridement samples 67.30% of the time, while 42.10% matched the pathogenic bacteria. Conclusions: For bacterial culture, 5 or more samples can improve the pathogen detection rate. Bacterial culture of sinus tract samples is not recommended as the basis for choosing appropriate antibiotics.

Objective: To compare the perioperative hidden blood loss (HBL) and analyze its risk factors in elderly patients undergoing intramedullary fixation after intertrochanteric fractures at different altitudes. Materials and methods: This prospective study collected the perioperative clinical data of 120 elderly femoral intertrochanteric fractures from February 2020 to February 2021 at different altitudes. Twenty-nine cases were from Nanjing, where an average altitude is 10 m (group A); 73 patients were from Xining, where an average altitude is 2300 m (group B); and 20 cases were from Yushu where an average altitude is 3600 m (group C). Demographic data of the included patients, preoperative and postoperative hemoglobin, hematocrit, prothrombin time (PT), activated partial thromboplastin time (APTT), preoperative and postoperative HBL, intraoperative visible blood loss, and perioperative blood transfusion rate, and other relevant indicators were recorded and the clinical data of the 3 groups were summarized. Results: The total HBL, preoperative HBL, and postoperative HBL of group C were greater than those of groups A and B, that is, total HBL: 740±380 mL in group A versus 850±530 mL in group B versus 1090±180 mL in group C, F=3.551, P=0.032; preoperative HBL: 460±320 mL in group A versus 410±300 mL in group B versus 590±120 mL in group C, F=9.086, P=0.011; Postoperative HBL: 270±220 mL in group A versus 440±420 mL in group B versus 500±140 mL in group C, F=13.138, P=0.001. Multiple linear regression analysis found that admission PT and APTT, fracture classification AO/OTA 31-A2.2–A3.3, male, body mass index, intraoperative blood transfusion, injury to operation time >5 days, longer operation time, and high altitude all were independent risk factors for perioperative HBL increase. There was a negative correlation between low altitude and hemoglobin on the first postoperative day and HBL. Conclusion: Elderly patients undergoing intramedullary fixation after intertrochanteric fractures develop massive HBL during the perioperative period, especially in patients in high altitude areas. Regular blood tests, PT, APTT during the perioperative period are vital to avoid perioperative anemia. Shortening the perioperative period and operation time will significantly reduce HBL.