I have a broken wrist which has been fitted with an external fixator.Does anyone know how long before the swelling in fingers goes down?

Was wondering this about my broken ankle, too. The last time they replaced the cast, I noticed that the swelling was still there. How long does it take for that to go down, and why would it still be so swollen after this long? The cast people didn't seem concerned, so I know it's not a dangerous thing. But, it still made me curious when I saw it.