Reattachment of the lower limb in traumatic amputations like this is rarely performed, except in children. The reasons are many.
1. Return of skin sensation after amputation is iffy. Having numbness on the bottom of your foot means you are very pre-disposed to having ulcers/wounds form. Think about it as if you had a piece of gravel in your shoe and couldn't feel it. Eventually, you will get an open wound, which will have a very difficult time healing.
2. The eventual ankle and foot function is marginal at best in adults after replantation. Significant contracture of muscles and tendons can occur after repair.
3. The function of healthy people who suffer a traumatic amputation is quite good, assuming they get a non-complicated well formed amputation. They actually have better outcomes in most cases than those patients that drag around a dysfunctional limb that has been salvaged.
4. Cold intolerance. Replantation of amputated parts often leads to cold intolerance. And even what would seem like a normal temperature for you to work in can become intolerable to the replanted part.
5. The limb would be somewhat shorter than the other. In upper extremity amputations, limb length is relatively meaningless as long as you get function. In lower extremity traumatic amputation, the loss of the injured tissue and bone always leads to some shortening. Obviously, this can be corrected with shoe lifts, etc. but it's another downside to lower extremity salvage.
I can assure you that, if I had a traumatic amputation of my foot, I would select a good below-the-knee amputation in a heartbeat. As humans, our hands define what we do and salvaging some function in an amputated hand is better than a prosthesis. The function of the lower extremity is to bear weight and get you from one place to the other, and a good BKA does that really well, especially in an otherwise healthy individual.