For relatively serious knee injuries, those who are in a position to do so should consult a medical professional, preferably an orthopedic surgeon engaged in the relevant specialty in a timely manner, to determine through examination whether it is conservative or surgical treatment, and not just find a hospital or a doctor to look at, let alone try to diagnose through their own speculation. Knee injuries that are missed by yourself happen all the time and often lead to serious consequences. For those who do not have access to a hospital, the following principles of protection (PRICE principles) should be followed during the acute phase: Protect: avoid further injury, protect with bandages, braces, casts, etc. Rest: Stop the activity, let the injured knee rest, use crutches. Ice: Ice can reduce the inflammatory response and pain, 30~45 minutes/time, after 15 minutes interval, you can continue to apply ice at least 4~6 times/day. Compression: Use an elastic bandage to apply slight pressure to the knee joint to reduce swelling. Elevation: Elevate the lower limb above the heart position to increase venous return and facilitate swelling. After the acute phase, you should visit the orthopedic clinic as soon as possible to avoid delaying treatment. Depending on the injury, the orthopedic surgeon will perform the appropriate physical examination, and if there is some severity, further radiographs, CT scans, magnetic resonance imaging (MRI), ultrasound, etc. may need to be performed to clarify the diagnosis. After a clear diagnosis, the next step of conservative or surgical treatment plan will be determined depending on the injury. Some serious intra-articular knee injuries such as cruciate ligament rupture, meniscal tear, and knee dislocation often require minimally invasive arthroscopic repair to restore the function of the joint.