The medial meniscus is “C”-shaped and its edges are connected to the joint capsule and the deep medial collateral ligament. The lateral meniscus is “O” shaped with a gap formed by the N tendon separating the meniscus from the joint capsule in the middle and posterior third, and the lateral meniscus is separated from the lateral collateral ligament. The meniscus has these important functions: 1) to enhance lubrication and facilitate knee movement 2) to act synergistically with the knee ligaments to guide joint movement 3) to make the tibial articular surface more suitable and stabilize the knee joint 4) to cushion and absorb shock to protect the articular cartilage 5) to transmit load 6) to regulate intra-articular pressure The meniscus has an extremely important role in joint weight bearing and joint stability, and it is undoubtedly necessary to protect the meniscus in general The meniscus should be preserved as much as possible during surgery. Nutrition of the meniscus: The meniscus has a blood supply at the edge of the meniscus and the joint capsule, so it should be repaired as much as possible after injury. The inner 1/3 of the meniscus has no blood supply and is nourished by the joint fluid. Symptoms of knee meniscal injury: 1. knee pain 2. joint swelling and fluid accumulation 3. joint interlocking 4. playing soft leg 5. joint rattling Types of meniscal rupture: oblique, longitudinal, laminar, barrel stem-like and transverse rupture In contemporary sports medicine, we will preserve the meniscus as much as possible in meniscus surgery, and have gradually abandoned meniscectomy. For injuries to the posterior horn of the meniscus and the body, a total internal suture is used; for injuries to the anterior horn of the meniscus, an external-internal suture is used, and we will make a comprehensive assessment according to the site and type of meniscus injury to make the most appropriate treatment for the meniscus.