RESUMO
BACKGROUND: Although it has been found in many studies that three-dimensional finite element analysis can be used in the study of knee joint biomechanics, there are few researches on different defect areas of medial condyle cartilage of the femur. OBJECTIVE: To analyze the stress change trend of perimeter articular cartilage before and after the occurrence of different defect areas of medial femoral condyle cartilage, providing biomechanical data for patients with knee medial femoral condyle cartilage defect. METHODS: One normal adult had been selected to establish a three-dimensional finite element model. Material mechanical properties were input to Abaques software with divided grid model. After controlling boundary condition with mechanical load, structural nonlinear finite element was calculated. First, the load stress distribution of knee cartilage and meniscus was observed under normal stress. Articular cartilage stress distribution was observed with load conditions in different defects (0, 6, 8, 10, 12, 14, 16, 18 and 20 mm) of medial femoral condyle. The stress changes on the cartilage were analyzed during the defect of medial femoral condyle. This study was approved by the Ethics Committee of First Affiliated Hospital of Kunming Medical University. The volunteer signed the informed consent. RESULTS AND CONCLUSION: (1) Material properties, boundary conditions and the introduction of loads were defined successfully. The stress cloud chart and its stress data were obtained from different diameter defects of cartilage in medial condyle of knee joint. According to statistical analysis, the stress on the femoral condyle and tibial plateau cartilage had significant changes compared with no defects when the medial femoral condyle cartilage had defects of 10 mm (area 0. 78 cm2) and 12 mm (area 1. 13 cm2). (2) The stress change trend of the cartilage of the medial condyle of the knee joint under the condition of different diameter defects was calculated based on the analysis of the application of three-dimensional finite element method. (3) Results suggest that the defect with the diameter of 10 mm (area 0. 78 cm2) of medial femoral condyle may be the minimum diameter advised for operation intervention of cartilage repair.
RESUMO
Objective To study the similarity of chemical fingerprints of different proportion of Gualoupi-Gualouzi and Fruc?tus Trichosanthis,so as to provide the theoretical basis for the reasonable proportion of Gualoupi-Gualouzi. Methods The HPLC fin?gerprints and the common patterns of 6 the proportion of the 6 kinds of compatibility(30:70,35:65,40:60,45:55,50:50 and 55:45)of Gualoupi-Gualouzi and Fructus Trichosanthis were established,and the similarity of chemical fingerprints of different compati?bility proportion of Gualoupi-Gualouzi and Fructus Trichosanthis between their common patterns were compared. Results Compared with the common pattern of Fructus Trichosanthis,the similarities of the common patterns of chemical fingerprints of the above 6 kinds of compatibility proportion of Gualoupi-Gualouzi were 0.8808 ± 0.0407,0.8930 ± 0.0236,0.8995 ± 0.0195,0.9033 ± 0.0190,0.9363 ± 0.0082 and 0.8904 ± 0.0144,respectively. Among them,Gualoupi-Gualouzi ratio of 50:50 had the highest similarity,and compared with other groups,the differences were statistically significant(P<0.05 or 0.01). Conclusion The optimum proportion of Gualoupi-Gualouzi can be determined by the fingerprint technology,which provides the theoretical basis for the reasonable proportion of Gualou?pi-Gualouzi.