My mom just had a knee replaced last week in FL. Prior to surgery, she had an hour-and-a-half MRI that measured her knee in extreme detail. The results were sent to a company in CA. They then produced a knee for her that was pretty much custom made (that's her explanation). She was in the hospital 3 days and then entered rehab for physical therapy and occupational therapy - she's not a spring chicken! If you are elderly or don't have much upper body strength, talk to your doctor about rehab. She is getting worked on for several hours a day. At home physical therapists will only come 3 times a week for an hour or two.