What is arthritis?
Arthritis is an acute or chronic
inflammation of a joint and its surrounding soft tissues. It is characterized by
progressive joint deterioration with loss of the smooth "cushioning" cartilage
which lines joints, resulting in bone against bone wear. This wear causes
structural changes visible on x-rays. The stabilizing soft tissues may also
deteriorate. Arthritis is frequently, but not always, painful and eventually
results in limitation of motion, joint deformity and loss of function.
What are the types and causes of arthritis?
The most common form of arthritis,
degenerative arthritis or osteoarthritis, may affect one or more joints anywhere
in the body. Principally, the hands and the weight-bearing joints in the lower
extremities are involved. Degenerative arthritis is characterized by progressive
deterioration of joint cartilage. It is a local disorder without systemic
effects. Its onset is directly related to aging, but its true cause is largely
unknown. A number of factors are thought to be important in the development of
this disease. Mechanical considerations (e.g., joint stability and alignment),
affect the distribution of forces across the joint and therefore impact the
joint's longevity. Traumatic injuries and infections resulting in joint
irregularities and heavy usage are risk factors. Some persons inherit the
tendency to develop degenerative arthritis, though this genetic predisposition
is not well understood. Typically, these individuals are affected at an earlier
age. Think of degenerative arthritis as the accumulation of wear and tear on our
joints from a lifetime of activity.
Arthritis may also result from a systemic
inflammatory condition, the most common and debilitating of which is rheumatoid
arthritis. Rheumatoid arthritis is a disease of the synovium, a tissue which
lines and nourishes joints and tendons throughout the body. As part of this
condition the synovium proliferates causing local destruction of bones, joints,
and soft tissues. Commonly the disease begins in peripheral joints (hands and
feet) and is often symmetrical, eventually involving multiple joints. Its cause
is also unknown though genetic factors are thought to be critical. Think of
rheumatoid arthritis as an inflammatory disease that affects the entire body,
especially joints.
Who is affected by arthritis?
Degenerative arthritis affects virtually
everyone, especially older patients. Females are usually more commonly affected
than males and often at an earlier age. X-rays reveal joint degeneration in
approximately 60% of adults over age 60 and 80 to 90% of patients over age 75.
Inflammatory arthritis, specifically rheumatoid
arthritis, affects about 2.5% of the adult population. Women are three times
more likely than men to develop this disease. Though it may strike persons of
any age, the peak age of onset is between ages 20 and 40 years.