My knees are sh@gged, have been since i was twelve.
key-hole exploration, double lateral release, numerous physios, osteos, accupuncture, painkiller habit, pain management courses..
you name it, i think i've tried it.
the best things that worked for me are the strengthening exercises the physio gave me, the accupuncture (although it had me in tears the first time and needed tweaking and made me throw up the second time) and understanding how to manage/cope with the pain.
I've given up with the docs/medical profession. the last specialist i went to see told me that the lateral releases i'd had when i was 18 were either no use at all, or detrimental..brilliant.
interestingly i find cycling less strain than say, standing or walking for long periods of time.
Can't really offer you too much advice jax13, as knees joints are more than a little complex. Try a little of everything and see what works best for you
Hope they start feeling better soon mate, and apologies for slightly ranting lilt of the post!