Someone who has severe cartilage degeneration may not have reached the point where the surrounding structures have become irritated and inflamed. If only cartilage is involved, there will be no pain because cartilage doesn't have any nerve endings. By contrast, the person with minimal X-ray findings of cartilage degeneration may just be unlucky enough to have the cartilage degrade in a pattern that allows pressure to be placed on the surrounding structures, leading to irritation and inflammation. Perhaps the synovium was already inflamed, or perhaps the bone was already compensating for increased pressure, and a tiny bone spur hooked a piece of the joint capsule or irritated a ligament.
Find out more about this book:The Arthritis Handbook: Improve Your Health and Manage the Pain of Osteoarthritis (A DiaMedica Guide to Optimum Wellness)