Noisy knee

I had Grade 2 Bends in October 1997, from which I fully recovered within 3 months . In February of this year I had ACL reconstruction surgery on my left knee. the Surgeon used a hamstring from the same leg, and went in such a way as to minimise disturbing the patella.
While the operation has been a success it has left me with severe crepitus (not sure if that is the correct way to spell it) in my left knee. My Doctor says that this is the worst case of crepitus he has come across (he has been operating for many, many years!) and is surprised that I have it due to the type of operation he did. He thinks that the noise is caused by to high water content in the cartilage and the patella, but rather than doing anything about it he wants to see if the noise changes in the next few months. So far the crepitus noise has not changed in volume or type of sound since 1 May. The noise happens whenever the knee is bent or straightened, even when seated and baring no weight. There is no pain or swelling. I was wondering if you know of any research into joint noise, or joint noise linked to diving related injuries, and if there is anything I can do to aid my recovery?

I must admit I have not had such a case reported to me before.
With regard to diving, I do not see that a crepitant knee which is fully functional in all other ways can be a prohibition to diving as long as the necessary recovery period is adhered to.
the only problem may result from an altered blood supply to the tissues of that knee as a result of the surgery which may have a bearing on its ability to off-gas nitrogen in the same way as a normal knee.
also should a pain develop in that knee post dive, there may be a problem to diagnose correctly if this is due to decompression sickness or musculoskeletal damage.
however, I do not consider this a serious problem and, permit me to state again, if the knee is given the recovery time recommended by your surgeon before indulging in strenuous activity, you can dive as you did before your operation.