So about that, I have some sort of Chondral Fissuring of both knees. Essentially, the Cartilage for both knees has deep cracks and fissures through it, some of it has also started peeling off of the bone, and there a small, loose bits of cartilage floating around the knee too.
Theres no surgical options, supposedly (Rheumatologist tells me that, so does my GP and Physio), so the best Cure is to Grind back the Cartilage with low-impact leg exercises.
I had to buy a particular Exercise bike, that has a heavy flywheel (7kg), set the resistance up, so it's like pushing a weight, a slowly do that for 30 minutes a day. This not only builds muscle, but grinds back all my broken cartilage, and hopefully creates a new groove for my knee caps to sit in. Unfortunately it's a long, slow, painful process, slowly improving every week.
Option B is to take Anti inflammatory pills for the rest of my life, with monthly (expensive) Steroid Injections and fillers (with the risk of infection from each one).