JG -- my father in law is an orthopedist, I can get you detailed answers to any specific question if you have them. I've also had ACL reconstruction and know a good local (seattle) guy if you want him. He is (for as long as they're in Seattle) also the Sonics team orthopedist--a good and talented guy.

Re: the arthroscopic surgery to clean up the meniscus -- will it be a complete removal, or removing only the damaged part (which seems much more likely). Get them to estimate the percent they're removing, it'll help you evaluate options.

Total knee surgery has come hugely far in the last 10-20 years, I know both doctors and patients who swear this surgery is borderline magic at this point. Most people are afraid of the surgery (it does, indeed sound scary) but the vast majority kick themselves afterwards for waiting so long, because the results are very good.

My 2c, knowing next to nothing about your specific situation, is to have the scope/cleanup done and see if that buys you a few (10?) years. The total knee prosthesis and techniques are only getting better and better... Postponing so long as you're comfortable seems reasonable. But even if you have to or decide to do the total knee sooner than later, I believe you'll be happy with the results.