The discoid cartilage of the knee is a morphologic abnormality of the meniscus of the knee. Because the disc cartilage is wider and thicker than the normal meniscus, the lateral meniscus is more prone to degeneration, injury, and rupture than the normal meniscus. In most cases of disc cartilage injury, there is only lateral pain or a positive gravity test in the early stages, and there are no typical symptoms of interlocking. Therefore, the timing of surgery for symptomatic disc cartilage injuries often varies greatly. With the development of arthroscopic techniques, there are more reports on the treatment of disc cartilage injuries in the domestic and international literature, but there are few reports on medium- and long-term follow-up in the domestic literature, and there are fewer discussions on the timing of surgery. In order to evaluate the timing and clinical efficacy of this procedure, we conducted a follow-up of patients with arthroscopic surgery from 0.5 to 8 years after surgery and obtained our own statistical results. Patients and methods A total of 46 patients (54 knees) treated by arthroscopic surgery in pediatric orthopedics in Beijing were followed up. During the follow-up, we recorded the duration of preoperative symptoms, Lysholm score before surgery and at the last follow-up, clinical manifestations and physical examination (including pain, swelling, presence of interlocking, quadriceps atrophy, knee extension, internal and external rotation stress test, etc.), standing knee plain radiograph, intraoperative disc cartilage injury, combined injuries, and surgical approach (including molding, subtotal resection, and total resection). For patients suspected of disc cartilage injury, the author used temporary fixation in plaster for the first 3 weeks after the injury due to more intra-articular bleeding in the acute phase, which affected the accuracy of the MRI diagnosis, and then performed MRI after the intra-articular fluid was absorbed. Among them: male: 16 cases, female: 30 cases; left side: 29 knees, right side: 25 knees; mean age: 10.5 years (3-15 years); mean follow-up time: 38 months (6-111 months); molding: 19 knees, subtotal resection: 10 knees, total resection: 24 knees, suture plus molding: 1 knee. Case information was obtained in all 46 cases and postoperative Lysholm scores were performed by telephone follow-up. 32 of the 46 cases returned to the hospital for physical examination, 16 of which received a repeat plain knee radiograph. Among them, 8 cases were followed up for more than 5 years. Statistical analysis: Paired t-tests were applied to compare the differences in Lysholm scores before surgery and at the last follow-up. The trend of preoperative Lysholm score of 60 was calculated in the three groups, and the trend chi-square test was applied to the results. The groups were divided into three groups according to the surgical procedure: disc chondroplasty group (group 1), subtotal resection group (group 2), and total resection group (group 3), and the differences in Lysholm scores at the last follow-up were compared by ANOVA. Statistical analysis was performed using the SPSS 16.0 software package. Results Lysholm score improved from 62.94 ± 17.94 preoperatively to 96.39 ± 6.42 postoperatively, with a significant difference (p<0.001). The relationship between preoperative symptom duration and preoperative Lysholm scores was compared in subgroups. A trend chi-square test was applied and revealed a decreasing trend in preoperative Lysholm scores with increasing duration of preoperative symptoms (p=0.037<0.05). Comparing the Lysholm scores at the last follow-up of the three different procedures, the difference was not significant (P=0.336>0.05). However, the absence of differences in Lysholm scores does not mean that there were no differences in all aspects. We analyzed eight patients who had been followed up for more than five years, and we found differences by comparing the Fairbank grading on plain radiographs of the knee joint at the last follow-up in eight patients. grade degeneration. Of the 54 knees preoperatively, 33 had extension limitation and 5 had flexion limitation, but none had limitation of joint motion at the final follow-up. No knee instability was observed at the last follow-up. It is discussed that the discoid cartilage of the knee may be congenital or an abnormal result of the development of the meniscus. The incidence is much higher in Eastern populations, including ours, than in Western populations. Discoid cartilage is more common on the lateral side, whereas medial discoid cartilage has been reported infrequently. In the anatomical statistics, the Western literature is 1. 4%-5%, while in Japan the reported incidence of discoid cartilage can be as high as 16. 6%. In China, the statistics are 8.2%-12%. Therefore, discoid cartilage of the knee and its injury are important topics in knee arthroscopic surgery. The traditional surgical approach of total resection of the disc cartilage will inevitably lead to degeneration of the articular cartilage, and Kim et al. found better results in the complete disc cartilage than in the partial resection group at a follow-up time of less than 5 years. However, at a follow-up of more than 5 years, there was no difference between the two groups. Radiologically, there was no significant difference between the two procedures at 5 years after surgery; however, after 5 years, the partial resection group had a better outcome than the total resection group. They concluded that the long-term results of meniscal arthroscopic surgery were related to the amount of meniscus removed. We analyzed 8 patients with more than 5 years of follow-up, and we further confirmed the above by comparing the Fairbank grading of the plain radiographs of the knee at the last follow-up of the 8 patients , and we found that there were differences. Okazaki et al. concluded, through a long-term follow-up of an average of 16 years, that the earlier the time of surgery, the better; otherwise, damage to the meniscal cartilage could lead to degeneration of the affected joint and affect the outcome of the surgery. In our follow-up results, it was found that the preoperative Lysholm score tended to decrease as the duration of preoperative symptoms increased (P=0.037<0.05). In addition, a total of five patients with disc cartilage and articular cartilage degeneration in the surgical record occurred in patients with preoperative symptom duration greater than 6 months. These two points provide further statistical support for Okazaki's view that there was a statistically significant (P<0.05) difference between the composition ratio of patients with preoperative Lysholm scores less than 60 when comparing the two groups A and B. Therefore, it is recommended that surgery should be performed as early as possible, within 3 months after definitive diagnosis. Clinically,patients with symptomatic discoid cartilage are the only ones to be seen in the hospital. With the improvement of arthroscopic theory and technology, there is an increasing tendency to preserve and repair as much meniscal tissue as possible? However, a few complex disc cartilage injuries with severe fragmentation often necessitate total resection. In adults, articular cartilage degeneration is often present before the onset of symptoms in disc cartilage injuries, which is one of the reasons for the poor surgical outcome. In children and adolescents, who were seen earlier, the articular cartilage is more capable of regenerating and repairing, so there is less articular cartilage damage secondary to meniscus injury. Conclusion: Arthroscopic disc chondroplasty or resection for symptomatic disc cartilage injury can effectively improve joint symptoms and function, but total resection should be avoided as much as possible; early surgical treatment should be chosen for persistent symptoms after the acute phase of knee disc cartilage injury; continued conservative treatment may aggravate knee symptoms and may aggravate disc cartilage and articular cartilage injury; mid-term follow-up results showed that there was no significant difference in Lysholm score between different surgical approaches. Lysholm's score was not significant, but Fairbank's grading of knee plain radiographs was different, and the difference in clinical performance may gradually appear over time.