Discoid meniscus of the knee is common in Chinese, mostly located on the lateral side. It is a congenital meniscus abnormality, which itself is hypertrophic and prone to degeneration or tearing and jamming the joint to produce symptoms. Most patients have degenerated and torn the meniscus significantly at a young age, and if it has a greater impact on walking or is more painful, conservative treatment is ineffective and arthroscopic surgery can be performed. Some of the disc meniscus is difficult to preserve because of the complex tear and poor quality, and the joint may degenerate later after complete cutting. However, some scholars have suggested that the joint degeneration is not so obvious after complete removal of the disc meniscus compared with the normal meniscus, which may be related to the fact that the degenerated and torn disc meniscus itself has little effect but wears out the joint.