The lateral disc meniscus is more commonly seen in the Asian population than in the West. The lateral discoid meniscus is more prone to tearing because it is morphologically larger and thicker than the normal meniscus, especially in adolescents with high athletic intensity. With the exception of asymptomatic meniscal tears, which can be treated conservatively, most adolescent patients require surgical treatment, and depending on the location and type of tear, most severely injured menisci undergo partial, subtotal, or total removal. Although surgery temporarily relieves clinical symptoms, there are no previous studies on whether there is an effect on the lower extremity axis in adolescents. The results of a study conducted by Professor Jiang Qing’s team at the Center for Joint Diseases, Nanjing Gulou Hospital, China, were published in a recent issue of J Bone Joint Surg Am. This retrospective study included 298 adolescent patients (under 20 years of age) who underwent arthroscopic surgery at their joint center between 2004 and 2013. Patients were divided into 3 groups based on their meniscus morphology: group A (lateral disc meniscus tear), group B (lateral non-disc meniscus tear), and group C (lateral non-disc meniscus with no tear). The standing tibiofemoral angle (TFA) and mechanical axis deflection (MAD) of the patients were measured before and after surgery, respectively, and the lower extremity axial differences were compared before and after surgery and between the discoid non-discoid meniscus. The results showed that the preoperative TFA and MAD showed that group A had a more pronounced valgus deformity compared to group B or C. Compared with the preoperative period, the TFA and MAD were significantly reduced in groups A and B after surgery, and the reduction was more in group A, while there was no significant change in group C. Adolescent patients with lateral disc meniscus tears exhibited more pronounced inversion compared to non-disc or normal meniscus, and resection resulted in significant valgus changes. In patients with severe inversion deformity, the inversion angle may decrease and normalize postoperatively. Patients without inversion deformity, however, are prone to postoperative ectropion deformity. Partial meniscectomy also produces a tendency to ectropion, but discoid meniscus is more severe than non-discoid. It has been shown that lateral discoid meniscectomy has little effect on the lower extremity axis in middle-aged adults, but this study showed that the effect of surgery on the axis was significant in adolescents with either discoid or nondiscoid meniscal tears, and even more so with discoid meniscus. In the short term, the lower extremity axis in adolescents changes rapidly after surgery, but for the long term, the benefits and drawbacks are unknown. Lesson: Therefore, meniscal injuries in adolescents should be preserved as much as possible with less resection or suturing of their meniscus.