If your leg is swollen after being hit, you should go to the emergency surgery or orthopedics department of the hospital to have your leg photographed to see if there is any fracture or dislocation. If there is, external fixation in plaster, external fixation by manipulation, or internal fixation by surgical incision is needed to effectively maintain the local fracture in a stable state and to allow the ligaments and joint capsule of the joint to be fully repaired. If there is no obvious fracture, it means that the collision has caused damage to the local skin, subcutaneous and muscle soft tissues, and in this case, oral anti-inflammatory and pain-relieving, blood-stasis-activating, tendon-relaxing and circulation-improving drugs can be taken to reduce local swelling. In the acute stage, cold compresses should be applied to reduce the local swelling, and the injured position should be elevated to promote the metabolism and absorption of bruises through the effect of gravity. If the swelling is so pronounced that the peripheral nerves and blood vessels are compressed, resulting in decreased sensation or blood supply problems at the distal end, this condition is caused by osteo-fascial compartment syndrome and requires surgical decompression of the osteo-fascial compartment to avoid further compression of the nerves and blood vessels.