I'm not sure if this is still relevant but I noticed that 1) you had not had any replies and 2) we have almost the same hobbies as well as similar injuries. I paraglide instead of motocross!
What your doctor was talking about is called a Manipulation under Anaesthetic and I have had 2 done but not for my current rehab. It sounds horrible but as you are right out of it in the Land of Nod you are completely unaware of what is going on. What they do is put to into a very deep relaxing sleep then see how much ROM (so flex and extension) you have when all your muscles are relaxed. If they feel anything blocking the ROM then they may go in arthroscopically to see what it is or just manipulate the blockage away. Usually it is a mass of scar tissue and simple repeated movement can break it up enough without having to go in. Sometimes they realise that it might be something else, like a small meniscus tear or that the scar tissue is too dense so they go in and sort that out.
As I said, I have had 2 done and both times it helped me regain considerable improvement in my ROM. Once they went it and found a small tear which was blocking the movement and the repaired it, the other time they did not need to go in. When I woke up both times I obviously had a lot more pain initially but it soon went away and the gains I made far outweighed the couple of days or so of increased pain.
I hope this is helpful to you - let me know if I can help in any other way at all. I have a small thread where I am recounting my rehab from my last op (August 14th this year) which included a PLC and LCL reconstruction - you'll find it in the Cruciates Section as that was my major injury.
in the Alps!