Hello-- I too was terrified to have another hip replacement. I told the prospective surgeon about the fears. I found that the surgeons are receptive to helping with relieving the fears.
It's important to go into this with optimism and trust in the surgeons skills and intention to improve the quality of life of the person on the table. It is also important to ask to go to rehab hospital to help you start your recovery, if you feel you may need that support. What supports do you think you will need?
My your fears be replaced with trust in yourself, the system and your surgeon.

As to letting go of smoking, when your time is right you will do it.
What factors and experiences will benefit your moving towards letting the desire to smoke be an experience of choice, to smoke a cigarette or to not smoke a cigarette without judgement - good or bad? This is what I found was my process. I know that each person is unique and their path maybe very different. Choose the path that calls to you.