If you have the fusion you will not be able to move the knee out of that position (No crap hunh). Just try to do the things you are wanting to do after surgery with your knee in the position it is going to be fused.If you are ok with that, then that is great. Another option may be amputation.est Answer: Have the knee fused ONLY if ALL ELSE has failed. Knee fusion is a LAST resort and really a poor one. You will NOT be able to drive, or walk without a limp. Sitting will be a problem and you will have one leg (the fused one) straight forever more. There is no turning back once this is done.