Mike,
This April will be 5 years of having my left knee replaced. Best thing I ever did. I am pain free and was able to get back to a normal life. I hike, wade, mountain bike and work out at the gym 4 days a week. I agree with Larry 100%. Your effort in rehab will be your key to success. If you work hard and work through the pain your recovery should get you back to near 100%. All the people I know who had problems with their hip and knee replacements did not work hard in their rehab. Good luck, modern medicine is amazing.
Lanny