Osteoarthritis Causes
For most people, the cause of osteoarthritis is unknown, but
metabolic, genetic, chemical, and mechanical factors play a role in its development. It is
associated with the aging process and is the most common form of arthritis.
It may first appear without symptoms between 30 and 40 years of age and is present in
almost everyone by the age of 70. Symptoms generally appear in middle age. Before the age
of 55 it occurs equally in both sexes. However, after 55 the incidence is higher in women.
The cartilage of the affected joint is roughened and becomes worn down. As the disease
progresses, the cartilage becomes completely worn down and the bone rubs on bone. Bony
spurs usually develop around the joint.
Systemic symptoms, sometimes associated with other arthritic conditions, are not
associated with osteoarthritis. The joints of the hands and fingers, hips, knees, big toe,
and cervical and lumbar spine are commonly affected.
The degeneration of the joint may begin as a result of trauma to the joint,
occupational overuse, obesity, or mal-alignment of the joints (for example being
bow-legged or knock-kneed).
Until the late 1980s, OA was regarded as an inevitable part of aging, caused by simple
"wear and tear" on the joints. This view has been replaced by recent research
into cartilage formation. OA is now considered to be the end result of several different
factors contributing to cartilage damage, and is classified as either primary or
secondary.
Primary osteoarthritis Causes
Primary OA results from abnormal stresses on weight-bearing joints or normal stresses
operating on weakened joints. Primary OA most frequently affects the finger joints, the
hips and knees, the cervical and lumbar spine, and the big toe. The enlargements of the
finger joints that occur in OA are referred to as Heberden's and Bouchard's nodes. Some
gene mutations appear to be associated with OA. Obesity also increases the pressure on the
weight-bearing joints of the body. Finally, as the body ages, there is a reduction in the
ability of cartilage to repair itself. In addition to these factors, some researchers have
theorized that primary OA may be triggered by enzyme disturbances, bone disease, or liver
dysfunction.
Secondary osteoarthritis Causes
Secondary OA results from chronic or sudden injury to a joint. It can occur in any
joint. Secondary OA is associated with the following factors:
- Trauma, including sports injuries
- Repetitive stress injuries associated with certain occupations (like the performing
arts, construction or assembly line work, computer keyboard operation, etc.)
- Repeated episodes of gout or septic arthritis
- Poor posture or bone alignment caused by developmental abnormalities
- Metabolic disorders.
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