There are two possibilities here: firstly, due to the heavy soft tissue damage of the body caused by the fracture, there will be more and more swelling after the fracture. Generally the swelling lasts for 48-72 hours, and after reaching the peak, the swelling will gradually subside. Secondly, there is a problem with the tightness of the cast, which may be too tight, and at this time the affected limb should be elevated and treated with dehydrating medication. If the swelling gets worse, it is important to go to the hospital for further examination by an orthopedic surgeon to determine if there is an osteofascial compartment syndrome. If there is an osteofascial compartment syndrome, it is necessary to incise the limb. Otherwise, it can easily lead to necrosis of the distal limb, which plays a crucial role in the function and survival of the limb.