In reply to Gav Parker:
Had a knee arthroscopy but not for the same reason as you. Would I have it again - no, or not at least unless there were no other non surgical treatments possible. I'll not go into detail but it left me with more problems than I had before.
My GP advised caution at the time and suggested some surgeons operated too quickly. Since discovered that at least some knee arthroscopy ops have very limited or short term benefit and the risks of an op have to be put into that context.
Maybe I was the 1 in a .... whatever to be in a worse position, but you have suggested that it maybe muscular. If you are in any doubt about the consultant's advice, get a second opinion first, and also explore all other treatments.