Has anybody had surgery to remove a carpal boss (bony overgrowth)?

Yes : I have no had it done myself but have done a bunch. It involves a small incision on the back of the hand, the boss is removed. After you can return to light activity in a couple of days full activity in 10 days to 2 weeks.

I have done this: Carpal bosses are bony overgrowth at the junction of the metacarpals and wrist bones and are usually associate with osteoarthritis of the underlying joints. They have a tendency to recur after removal unless the underlying arthritis is treated.