revision acl/sixth surgery - should I?

I'm 50 years old and am scheduled to have an acl revision surgery next month, which would make it my sixth surgery on my left knee. However, I had my first scope to remove cartlidge about 27 years ago, and my acl reconstructed around 20 yers ago. Around 5 years ago I learned that my reconstructed acl was no longer functional, and it was recommended from my original surgeon not to get the revision due to the previous trauma and surgeries. Consequently, I've been having more problems with the knee giving out as well as hip and groin problems probably due to my biomechanics being off. I've also had three opinions on what to do. The first os told me that it would be no problem because I was in excellant shape for my age, and that I should be able to be as active as I'd like. He also told me that I could rehab on my own. The 2nd os told me that he'd put me under and see how bad my knee was, then he'd determine what to do. He also advised me to see my original os since he's familiar with my knee. Therefore, I met with my original oa again and he cautiously agreed that a revision should be done using an allograft, but was worried about possible complications since the knee has been compromised from the previous surgeries and has some arthritis in it. So, since I'm a young 50, (my Dr. said my age was nothing to worry about), and in graet shape, very active, and have young children, I've decided to get the revision. My questions are: Should I be overly worried about coming out of the procedure worse than when I came in? and has anyone else been in a similar situation as mine?