In reply to Gecko1977:
Like many on here, I suspect, I have had both a full knee replacement and a full hip replacement. Recovery from the knee op. was quite slow and painful - it was almost two years before I felt the full benefit, but, once I did, it was great. I was about 60 when it was done and for the last five years have been able to climb no worse than I was before (sadly no better either). The hip replacement was very easy by comparison and I was able to climb carefully just three weeks after the op.. The main issue with the knee was regaining good flexibility/bend, but it just required consistent effort and exercise. Both operations were done by the NHS and every aspect of treatment and care was excellent.
Like you I had reached a point where I felt I had no alternative, even for everyday living, but the outcome was much better than I was led to expect by the surgeon. It most definitely does not need to be the end of all the fun.
Good luck if/when you have it done!
John.