I am not sure what you mean by "knuckle" surgery. I do a lot of hand surgery but do not what you are referring to with this description. Any hand surgery that involves joints can be quite painful initially and require an extended period of recuperation including, at time, hand therapy.

When the surgery is completed, you have to keep the hands elevated to prevent pain and swelling. Your input to this is important in keeping pain and swelling to a minimum. There is also the movement that the doctor will describe that is very important. Make sure the doctor is qualified and experienced.

Well it depends on the surgery. Overall, hand surgery is mild or moderately painful. Not severe.

It is difficult to make a generalization, as there are many reasons why you would have surgery on your knuckles. However, in general this type of surgery is usually not very painful and usually resolves after several days.