I have flexible flat feet and i want to undergo a surgery, will i have a metal stuff in my foot for life? which type involves minimal scarring? can this surgery fix my knee position?

Never heard the term flexible flat feet. You almost certainly do not need surgery but only a Dr who has talked to and examined you can help with this question.

I’m sorry but I have to disagree with Dr. Grimm. Flexible flat feet and younger people can be a very serious and ongoing problem. This all has to do with what’s called biomechanics of the lower extremity. Did you try conservative care like custom orthotics muscle stretching and strengthening? if conservative methods did not work then surgery is a serious consideration.