1) Is there a similar English word - apt to a broken leg?
2) Did someone read the original version? which was the original word?
I've had a quick look for you at the many web sites that review the book but I can't see anything. I saw an interview with him and he talked about his serious accident. Maybe he said that he had a "gammy leg"? I can't think of anything technical that would fit the bill.
I'll see if I see it on my travels, maybe AnnaS the well known old-hand could take a peep as she has good access to a bookshop.
Of course if his leg is as flexible as Regan's neck then we might have alot of words to go through!