First off, you need a good surgeon, who simply won't work in a bad hospital. Second, going to rehab for two weeks instead of going home means PT every day, therapists who prod you into progress. Rehab also helps you keep the incision area immaculate and the nutrition appropriate. It saves you from a family that expects you to be 100% back in service. Third, when you get home, you can't just go to PT three times a week, you have to push yourself to repeat the therapy on the other four days. If you don't, you will regress, you blame the hospital and the MD, you are weak and angry. Then you push the prosthesis past it's limits and it fails.