There is a procedure that adds fat from your own body to you ankles, by doing a sort of liposuction in any part of your body and place in your ankles.
This is called "enxerto de tornozelo" in Brazil.
Good luck in your search!
I have the same issue....really wish there was something available to fix it but I have scanned the internet for over 5 years and nothing. I guess we will continue to wear long skirts and slacks!
This is a somewhat unusual request. It may be possible to fill the area with fat transfer grafting, but I have no experience with this procedure in that location.