Swelling and pain after a knee injury, it is necessary to apply cold compresses at an early stage, you can use frozen mineral water or ice cubes to apply cold compresses, which can play an early role in relieving pain, bleeding and swelling, you can also use Yunnan Baiyao spray, which can also play an early role in relieving pain, bleeding and swelling, and at the same time, you need to immobilize the knee joints, so as to prevent the knee injury from aggravating. Also early to the hospital for X-ray examination of the knee joint to rule out whether there is a fracture, if there is a fracture, according to the fracture of the surgery or plaster fixation. If there is no fracture, it is usually necessary to brake for 2-3 weeks. If there are obvious signs of bleeding in the knee joint, such as bruises and ecchymosis, pressure and pain in the ligaments of the knee joint, and instability of the joint, it is necessary to take an MRI of the knee joint at an early stage to check whether there is any damage to the meniscus of the knee joint and the ligaments, and if there is any damage, it is necessary to carry out treatment at an early stage in accordance with the degree of damage.