When edema occurs after a fracture of the arm, it is important to determine how long it will take for the swelling to go down depending on the severity of the fracture injury and whether or not it has received regular treatment. If the arm has a crack fracture, an incomplete fracture or a green branch fracture, the fracture end is relatively stable, the alignment is good, the surrounding soft tissue damage is not too severe, and the swelling is not too severe, the swelling can completely subside in about 2 weeks if the arm is treated with regular external fixation. However, if the arm has a comminuted fracture, or if the fracture is not treated regularly, and the fracture end is more obviously misaligned, the swelling may take about 3-4 weeks or even 6 weeks to subside.