If the knee hurts when tensed, the following measures should be taken: 1. The knee should be fixed and braked, for example, the patient can use an elastic bandage or knee brace to fix the knee joint here. If not, cardboard can be laid on the back side of the lower limb and a bandage can be used to bind the lower limb. 2. After taking the above measures, the patient must go to the nearest hospital orthopedic department and emergency department with the help of family members or ask for medical help to fully assess the cause of the current symptoms and provide targeted treatment. In this case, there may be a patellar fracture, cartilage damage, or damage to the anterior cruciate ligament and meniscus within the knee.3 Conservative treatment is preferred for mild cartilage and meniscal injuries, requiring strict bed rest, braking, and rest. The doctor will use an adjustable knee brace to completely immobilize the patient’s knee joint. This is supplemented by anti-inflammatory, anti-swelling, and pain-relieving medications.4 If there is a very serious injury, such as a patellar fracture or rupture of the anterior cruciate ligament, surgery is required.