Superficial cartilage defect is an important factor that causes osteoarthritis. Therefore, it is very important to investigate the influence of superficial cartilage defects on its surface morphology and mechanical properties. In this study, the knee joint cartilage samples of adult pig were prepared, which were treated by enzymolysis with chymotrypsin and physical removal with electric friction pen, respectively. Normal cartilage and surface treated cartilage were divided into five groups: control group (normal cartilage group), chymotrypsin immersion group, chymotrypsin wiping group, removal 10% group with electric friction pen, and removal 20% group with electric friction pen. The surface morphology and structure of five groups of samples were characterized by laser spectrum confocal microscopy and environmental field scanning electron microscopy, and the mechanical properties of each group of samples were evaluated by tensile tests. The results show that the surface arithmetic mean height and fracture strength of the control group were the smallest, and the fracture strain was the largest. The surface arithmetic mean height and fracture strength of the removal 20% group with electric friction pen were the largest, and the fracture strain was the smallest. The surface arithmetic mean height, fracture strength and fracture strain values of the other three groups were all between the above two groups, but the surface arithmetic mean height and fracture strength of the removal 10% group with electric friction pen, the chymotrypsin wiping group and the chymotrypsin soaking group decreased successively, and the fracture strain increased successively. In addition, we carried out a study on the elastic modulus of different groups, and the results showed that the elastic modulus of the control group was the smallest, and the elastic modulus of the removal 20% group with electric friction pen was the largest. The above study revealed that the defect of the superficial area of cartilage changed its surface morphology and structure, and reduced its mechanical properties. The research results are of great significance for the prevention and repair of cartilage injury.
Objective To explore clinical effect of failure mode and effect analysis in improving the submission rate of pathogen examination in counterpart supported high-altitude county hospitals, and formulate practical measures and methods suitable for high-altitude county hospitals to improve the submission rate of pathogen examination. Methods Patients admitted to the People’s Hospital of Ganzi County between January and December 2024 were selected. The data of hospitalized patients between January and June 2024 were as the control group, and the data of hospitalized patients between July and December 2024 were as the intervention group. The study analyzed and compared the submission rate of pathogen testing and the pass rate of microbiological test specimens before antimicrobial treatment between the two groups. Results A total of 3 984 patients were included. Among them, there were 1 748 cases in the control group and 2 236 cases in the intervention group. A total of 10 risk factors and 2 high-risk points were identified. There were statistically significant differences in the submission rate of pathogen specimens before antibiotic treatment [36.21% (633/1 748) vs. 49.33% (1 103/2 236); χ2=68.646, P<0.001] and the qualified rate of microbiological test specimens [26.75% (122/456) vs. 36.45% (261/716); χ2=11.910, P=0.001] between the control group and the intervention group. Conclusions Failure mode and effect analysis can effectively find out the weak points in low pathogen examination submission rate in high-altitude county hospitals. According to the high-risk points to guide the formulation of relevant measures, the pathogen submission rate in the region can be effectively improved.