Careful history and physical examination can confirm the diagnosis of 75% of meniscal tears. Acute injuries cannot be examined because of pain and swelling, so it is difficult to confirm the diagnosis through clinical examination and requires ancillary tests (such as MRI) to obtain the diagnosis. 1. Knee swelling: A simple meniscal tear can cause joint swelling and fluid accumulation, which is usually mild. If combined with intra-articular ligament injury and rupture then the swelling is more pronounced. 2. Quadriceps atrophy on the affected side: A longer history of meniscal tears is usually accompanied by quadriceps (i.e. anterior thigh muscles) atrophy, mainly on the medial side. This can be more clearly observed by comparing the legs bilaterally. 3. Knee pain: usually occurs in the joint space of one side. Joint pain can be caused by an inflammatory response caused by the involvement of the synovial membrane after injury, or by a torn meniscus pulling on the joint capsule. Some patients can also be painless. 4. Knee lock: After meniscal injury, the knee joint suddenly cannot be flexed or extended, which is called “stuck”. Often appear in the chronic phase. When walking or making a certain action suddenly can not flex and extend the knee, the production is accompanied by severe pain, that is, strangulation. This is caused by the sudden displacement of the ruptured meniscus between the femoral condyles and the tibial plateau, which can sometimes “unlock” on its own (often with sudden pain) during extension or twisting. The presence of this symptom is a strict indication for surgery and requires arthroscopic surgical unlocking treatment. 5. Knee popping: a crisp sound can be heard in the joint when moving, sometimes accompanied by pain on that side. The sound should also be constant in the joint space of one side. 6. Difficulty in walking up and down stairs and limited motion.