Study On The Ablation Effect Of Different Energy Levels Of Radio Frequency Ablation Systems On Torn Meniscus

Objective:To study on the ablation effect of processing meniscus with different energy levels of radio frequency. Methods: taking 30 pieces of fresh pig knuckles, use a marking pen to make a longitudinal mark of 1.5cm long in the middle of the medial meniscus body, and then use sharp-pointed scalpel(# 11) to cut through the meniscus along the marked line to the surface of tibial cartilage to make meniscal tear model and divide them into five groups randomly, including four experimental groups and one control group Use bipolar radio frequency gasification system under simulation arthroscopy at room temperature,(Artro Care company),and set it to the ablation file, according to different energy levels of file 2,4,6,8to process corresponding experimental group for 5 seconds, while setting a control group. Divide the processed specimen of each group into four parts after general morphologic observation: A, HE staining for histomorphology observation, and calculate the rate of empty cell; b, immunologic tissue staining observation and grading based on trisection system semiquantitative analysis; c, use FCM to calculate cell death rate; d, using scanning electron microscope(SEM) to observe the surface morphology and smoothness of fibrous cartilage. Results: With the increase of energy,the ablation effect of bipolar radio frequency is enhanced, gross observation: normal meniscal surface is smooth with bright white color, it touches strong and elastic, after each group is processed, the color becomes yellowish with the energy level increasing, but the incision and the surface area around it is smooth and bright, cutting marks may occur with greater energy levels,burnt brown spots are visible after 8-profile processing, and the area around the processed edge is hard. HE staining: normal meniscus tissue is composed of mass arrangement of collagen fibers, cell distribution is more loose, the size and shape are uniform, fibrous cartilage cell cytoplasm is red-stained and light-stained, the nucleolus is uniformly blue, deep-stained, the karyotheca is smooth. The injured and necrosis of fibro cartilage cells have large dispersing,broken and disappeared, and the empty-cell state is changed. With the improvement of the energy levels, the number of empty cells of fibrous cartilage gradually increases and the corresponding parts gradually become deeper, but without reaching full-thickness of the meniscus. I type collagen immunohistochemical result suggests that: the staining intensity of only file-8 group decreased, the staining intensity of the control group of file 2, 4, 6 is uniform and deeply stained. trisection system semi-quantitative analysis prompts: The I type collagen content of profile-8 group decreased, compared with the control group, it was statistically significant(P <0.05), the comparison of experimental group and control group had no significant difference statistically(p > 0.05).Flow cytometry was used to calculate the cell death rate of each group, which showed that with the increase of energy level, fibrous cartilage cell death rate had an increasing tendency, compared with the control group, the cell death rates of 2,4profile groups were not significantly different(P> 0.05), the comparative difference between 6,8 file group and the control group was statistically significant(P <0.05). The comparative difference between 6,8 file group has statistical significance(P<0.05). Scanning electron microscopy(SEM) showed the meniscus surface after modeling was uneven and not smooth, and it showed some cracks, but after the meniscus surface was processed through bipolar radio frequency, it showed that compared with the control group, the surface smoothness of file 2 group has increased, but uneven roughness could still be seen, as the energy levels increased, meniscal surface gradually became smooth, and the surface was becoming increasingly flat, in the 8-file group, there were no cracks and chips.Conclusion: When using bipolar radio frequency to repair the meniscal, with the increase of bipolar energy level, the number of empty cells of fibrocartilage gradually increases with the appearing area becoming deeper, but it doesn't reach full-thickness of the meniscus. The cell death rate and capability level of fibrocartilage is positively correlated, when the energy exceeds file 6, the death rate of fibrous cartilage is significantly increased. With the increase of bipolar radio frequency, the shape of meniscus processed by radio frequency becomes smooth, strong and surface flatness and smoothness are increased. The damage degree to the meniscus matrix of I type collagen of 8 file group is the largest. In clinical work, 4-file energy level should be chose to ablate meniscus.