He will ask you what you want to be able to do once he's finished with you. Think of the things you don't do because of the knee, and be HONEST with him about what you'd like to be able to do once treated. He will recommend a treatment based on your answers.

Lots of people opt for the total knee as a "do it and forget it" kind of treatment. You'll have more downtime and more rehab with this option, but it will last you longer. If you're considering a total knee, don't put it off and allow the joint to continue to deteriorate. You'll be compensating for the bad joint, and that leads to problems in the other knee, back, etc.