| |
Common Diseases > Osteoarthritis
Osteoarthritis, also
known as degenerative joint disease,
is the most common arthritic disease.
Scientists now believe osteoarthritis
results from a combination of genetic
abnormalities and joint injuries. In
this disorder, an affected joint
experiences a progressive loss of
cartilage, the slippery material that
cushions the ends of bones. As a
result, the bone beneath the
cartilage undergoes changes that lead
to bony overgrowth. The tissue that
lines the joint can become inflamed,
the ligaments can loosen, and the
associated muscles can weaken. The
sufferer experiences pain when the
joint is used. In addition to humans,
nearly all vertebrates suffer from
osteoarthritis, including porpoises
and whales, and long-extinct
terrestrial travellers such as
dinosaurs.
Joints & Osteoarthritis
Joints are designed to provide
flexibility, support, stability, and
protection. These functions,
essential for normal and painless
movement, are primarily supplied by
specific parts of the joint: the
synovium and by cartilage, including
collagen, its primary component.
The Synovium: The
synovium is a membrane that surrounds
the entire joint. It is filled with
lubricating liquid, the synovial
fluid , which supplies nutrients and
oxygen to cartilage, one of the few
tissues that does not have its own
blood supply.
Cartilage: The
cartilage is a slippery tissue that
coats the ends of the bones. It
contains a high percentage of water,
85% in young people to about 70% in
older individuals. This high content
is made possible by water-binding
qualities of large molecules called
proteoglycans, one of the primary
building blocks of cartilage.
Collagen:
Collagen, a major component of
cartilage, forms a mesh to give
support and flexibility to the joint.
Collagen is the main protein found in
all the connective tissues of the
body, which include the muscles,
ligaments, and tendons. The
combination of the collagen meshwork
and the high water content, tightly
bound by proteoglycans, creates a
resilient and slippery pad in the
joint, which resists the compression
between bones during muscle movement.
Osteoarthritis
Osteoarthritic Process: When
cartilage in a joint deteriorates,
osteoarthritis develops. The process
is usually slow:
- In
the early stages of the
disease the surface of the
cartilage becomes swollen,
and there is a loss of
proteoglycans and other
tissue components. Fissures
and pits appear in the
cartilage. In some sufferers
inflammation occurs around
the synovium.
- As
the disease progresses and
more tissue is lost, the
cartilage loses elasticity
and becomes increasingly
prone to damage due to
repetitive use and injury.
- Eventually
large amounts of cartilage
are destroyed, leaving the
ends of the bone within the
joint unprotected.
Other
problems occur as the body tries to
repair damage:
- Clusters
of damaged cells or
fluid-filled cysts may form
around the bony areas or near
the fissures.
- Bone
cells may respond to damage
by multiplying and growing
and by forming dense,
misshapen plates around
exposed areas.
- At
the margins of the joint, the
bone may produce
outcroppings, on which new
cartilage grows abnormally.
Location:
Unlike some other types of arthritis,
such as rheumatoid arthritis,
osteoarthritis is not systemic: that
is, it does not spread through the
entire body. Rather, it concentrates
in one or several joints where
deterioration occurs. Osteoarthritis
affects joints differently depending
on their location in the body.
- It
is commonly found in joints
of the fingers, feet, knees,
hips, and spine.
- It
is rarely found in the wrist,
elbows, shoulders, and jaw.
Fingers
Osteoarthritis of the fingers occurs
most often in older women and may be
inherited within families. It affects
areas where bony knobs form in the
joints, most commonly in the first
joint below the tips (known as
Heberden's nodes ) or less commonly
in the next joint down ( Bouchard's
nodes ). Gelatinous cysts, which
sometimes go away on their own, may
also form in the finger joints.
Osteoarthritis also frequently
damages the base of the thumb.
Knees
Osteoarthritis is particularly
debilitating in the weight-bearing
joints of the knees. Here, the joint
is usually stable until the disease
reaches an advanced stage, when the
knee becomes enlarged and swollen.
Although painful, the arthritic knee
usually retains reasonable
flexibility.
Hips
Osteoarthritis frequently strikes the
weight-bearing joints in one or both
hips. Pain develops slowly, usually
in the groin and on the outside of
the hips or sometimes in the
buttocks. The pain also may radiate
to the knee, confusing the diagnosis.
Those with osteoarthritis of the hip
often walk with a limp, because they
slightly rotate the affected leg to
avoid pain.
Spine
Osteoarthritis may affect the
cartilage in the disks that form
cushions between the bones of the
spine, the moving joints of the spine
itself, or both. Osteoarthritis in
any of these locations can cause
pain, muscle spasms, and diminished
mobility. In some cases, the nerves
may become pinched, which also
produces pain. Advanced disease may
result in numbness and muscle
weakness. Osteoarthritis of the spine
is most troublesome when it occurs in
the lower back or in the neck, where
it can cause difficulty in
swallowing.
Article Provided By
Activex America
Arthritis | Causes of Arthritis | Osteoarthritis |
Sport | Rheumatoid Arthritis |
Arthritis Tips |
|
|
|