Arthritis and other Rheumatic Diseases

Osteoarthritis

OA, the most common form of arthritis in the elderly, is characterized by focal degeneration of joint cartilage and new bone formation at the base of cartilage lesion (subchondral bone) and at the joint margins (osteophytes). OA can be defined as the result of both mechanical and biological events that destabilize the normal coupling of degeneration and synthesis of articular cartilage and subchondral bone and may be initiated by multiple factors, including [Page 51]genetic, developmental, metabolic, and traumatic causes. OA involves all tissues of the diarthrodial joint and is manifested by morphological, biochemical, molecular, and biomechanical changes of both cells and matrix that lead to a softening, fibrillation, ulceration, and loss of articular cartilage; sclerosis and eburnation of subchondral bone; and formation of osteophytes and subchondral cysts. OA is clinically characterized by joint pain, tenderness, limitation of movement, crepitus, occasional effusion, and variable degrees of local inflammation. The natural history of the disease takes approximately 20 years to be expressed, and most patients are age 60 years and older. Radiographic surveys reveal that the majority of respondents over 55 years of age have radiographically confirmed disease. It is estimated that 90% of people over 70 years of age have radiographic evidence of OA in at least one joint. Over 55 years of age, women are affected more than men. Between 40 and 50 years of age, there is little difference in male versus female prevalence.

Rheumatoid Arthritis

RA affects approximately 1% of the world's population. RA is a chronic, multisystem, autoimmune, and inflammatory disorder that involves peripheral joints in a symmetric distribution. The potential of the synovial inflammation to cause cartilage damage and bone erosions and subsequent changes in joint integrity is the feature of the disease. Symptoms include pain, stiffness, swelling of multiple joints, tenosynovitis, and bursitis. Inflammation may extend to other joint tissues and cause bone and cartilage erosion, joint deformities, movement problems, and activity limitations. RA can also affect connective tissue and blood vessels throughout the body, triggering inflammation in a variety of organs, including the lungs and heart, and increasing a person's risk of dying of respiratory and infectious disease. RA is a chronic disease that leads to joint damage within the first 2 years; is a cause of marked functional limitation; causes a 30% loss of work within the first 5 years, and shortens life by 5 to 7 years.

Chondrocalcinosis

Chondrocalcinosis (CC) or calcification within cartilage is usually due to deposits of calcium pyrophosphate dihydrate (CPPD) crystals. These deposits may be sporadic, familial, or secondary to a variety of metabolic abnormalities. The sites most commonly affected are the knee, wrist, and symphysis pubis. CC is readily visualized on plain radiographs, although sensitivity varies according to film and radiographic technique. Sporadic CC is seen most commonly and is age related.

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