A 68 year old man complained of aching pain around his left hip and right knee; it is worse after exertion and is relieved with rest. Both joints are tender and swollen, with pain and crepitus on passive motion. Tests for rheumatoid factor and antinuclear antibodies are negative, and ESR is normal. X-rays are likely to reveal all of the following, EXCEPT:
A. Joint space narrowing
C. Subchondral Bone Sclerosis
Ans: B. Osteoporosis
The clinical features and laboratory results of the patient described in the question are most compatible with the diagnosis of osteoarthritis (degenerative joint disease). Loss of joint cartilage and bony hypertrophy account for the typical radiographic findings. Early fibrillation of the articular cartilage leads to fissuring and decreased cartilage in the joint. Subchondral bone increases in thickness, becomes sclerotic, and forms osteophytes. Cystic areas develop below the joint surface and become filled with fibrous tissue (pseudocysts). The synovium contains inflammatory cells, and the joint capsule proliferates and fibrosis. Osteoporosis is not a feature of osteoarthritis.