Hi. I'm Brett, an orthopaedic nurse and an addict/alcoholic of the extreme variety.
Don't be afraid of your upcoming surgery, just be completely honest with the surgeons and don't let them fob you off without first coming up with a good pain relief plan and a good sliding scale plan to bring you down pleasantly after the surgery. When I worked at Stanmore Hospital we got loads of people who were addicted or had past addictions. It was only a problem when the patient felt that they could not be honest about their present or past problems.
Be honest, TRY and do as your told (difficult for people like us) and don't be afraid. All the best.....Brett
Hope you feel better soon!