I Had Two Back Surgeries The 1st One Was Ok

I had two back surgeries the 1st one was ok but 5 days after the 2nd one i got two infections pseudo..and morganella. they put a vacumn on me and a port in my for meds. i came home and was very sick with this...took me a long time to heal.
anyway seeing no one has told me why i got this, now have bone on bone in my rgt knee. Need a knee replacement badly pain 24/7 hardly walk. But am scared because of the last operation and what worse so is the doctor.
Can I get this again?