I have a friend who went in for a hip replacement (needed a new joint because the one already in was 20 years old and failing). She had two knee replacements and the other hip replaced. This time she didn't feel right when the doctor sent her home. She wasn't diagnosed with MRSA, but she spent a year in a rehabilitation center, returning to the hospital twice because of infections. The doctor doesn't want to risk another operation, so she sits in a wheelchair without a hip.
Another friend had complications, too, and was on all sorts of IVs at the hospital and at home. His attitude is that there are germs all over your own body and such infections happen despite the best attempts to stop them.
These articles tell about things you can do to reduce the risk of infection while in the hospital.
http://www.cbsnews.com/stories/2003/10/24/earlyshow/health/main579897.shtml
http://www.rense.com/general78/hosp.htm