Understanding osteoarthritis of the spine

Understanding osteoarthritis of the spine
June 7, 2005
By: Charles D. Ray, MD

About arthritis and osteoarthritis
ÏArthritisÓ is a general term that describes many different diseases causing tenderness, pain, swelling, and stiffness of joints as well as abnormalities of various soft tissues of the body. Of the combined term, ÏarthrosÓ means a joint and its attachments, and ÏÒitisÓ means inflammation. Various forms of arthritis affect nearly 50 million Americans and contribute to the majority of all physical disabilities. Although arthritis is ultimately associated with a wearing out of joints, nearly a half million children are also affected.

Of the several varieties of arthritis, the most common, the most frequently disabling, and often the most painful is osteo- (meaning bone) arthritis, mostly affecting the weight bearing joints (hips and knees) plus the hands, feet and spine. Normal joints are hinges at the ends of bones usually covered by cartilage and lubricated inside a closed sack by synovial fluid. Normally, joints have remarkably little friction and move easily. With degeneration of the joint, the cartilage becomes rough and worn out, causing the joint halves to rub against each other, creating inflammation with pain and the formation of bone spurs. The fluid lubricant may become thin and the joint lining swollen and inflamed.

Osteoarthritis is also known as degenerative joint disease and affects up to 30 million Americans, mostly women and usually those over 45 or 50 years of age. All races in the U.S. appear to be equally affected. This article focuses on osteoarthritis of the spine, particularly on facet joint arthritis.

Where osteoarthritis occurs
Cartilage is a form of usually slick, slightly elastic, connective tissue that covers the ends of the bone joints. In part, cartilage serves as a protective shock absorber to minimize the impact of bouncing, jumping and other types of daily activities on the joints Ò and is thus subjected to considerable wear and tear during life. Indeed, heavy work, sports, repeated injuries and obesity take a heavy toll on the joints of the limbs and spine. To be healthy, all joints should be exercised, but if this is excessive, joint damage may accumulate slowly. In addition to the hips, knees and lower back, arthritis commonly occurs in the neck, small finger joints, the base of the thumb, and the big toe. In the fingers, nodes (masses of bone and cartilage) can form on either side of the nail bed or the margins of joints to become reddened, tender and swollen. Cartilage breakdown in the hips and knees can be severe enough to require joint replacement. Osteoarthritis found in other joints, such as the hinge of the jaw, is often due to injury or stress.

Osteoarthritis of the spine
Spinal arthritis is one of the common causes of back pain. Spinal arthritis is the mechanical breakdown of the cartilage between the aligning facet joints in the back portion (posterior) of the spine that quite often leads to mechanically induced pain. The facet joints (also called vertebral joints or zygophyseal joints) become inflamed and progressive joint degeneration creates more frictional pain. Back motion and flexibility decrease in proportion to the progression of back pain induced while standing, sitting and even walking. Over time, bone spurs (small irregular growths on the bone also called osteophytes) typically form on the facet joints and even around the spinal vertebrae. These bone spurs are a response to joint instability and are natureÌs attempt to help return stability to the joint. The enlargement of the normal bony structure indicates degeneration of the spine. Bone spurs are also seen as a normal part of aging and do not directly cause pain, but may become so large as to cause irritation or entrapment of nerves passing through spinal structures, and may result in diminished room for the nerves to pass (spinal stenosis).

Osteoarthritis in the spine is anatomically divided into:

* Lower back (lumbar spine) osteoarthritis, sometimes called lumbosacral arthritis, which produces stiffness and pain in the lower spine and sacroiliac joint (between the spine and pelvis).
* Neck (cervical spine) osteoarthritis, sometimes called cervical spondylosis (spondy- implies the spine, and Òosis is an abnormal condition), which can cause stiffness and pain in the upper spine, neck, shoulders, arms and head.

Causes of osteoarthritis and spinal arthritis
There are a number of reasons why some people are particularly disposed to osteoarthritis. However, as with nearly all abnormal conditions affecting the body, it is likely that a combination of risk factors work together to cause osteoarthritis. As indicated above, repetitive trauma to the spine from repetitive strains caused by accidents, surgery, sports injuries, poor posture, or work-related activities are common causes of spinal arthritis. Therefore, athletes and people with jobs that require repetitive, and particularly heavy, motion have been found to be at greater risk. Other known risk factors for developing spinal arthritis include:

* Aging: steady and advanced aging of spinal structures, beginning in the 30Ìs, often work-related
* Gender: osteoarthritis being more common in post-menopausal women (although below age 45, it is more common in males)
* Excess weight: causing more stress on weight-bearing joints and the spine, particularly during the middle age years
* Genetics: having a family history of osteoarthritis or congenital defects of joints, spine, or leg abnormalities
* Associated diseases: the presence of other associated diseases, infections, diabetes, and various other forms of circulating arthritis, such as rheumatoid arthritis or gout

When a specific cause of the osteoarthritis is unknown, as it is in most cases, it is referred to as primary osteoarthritis, which appears to be mostly due to aging. Aging leads to changes in cartilage and synovial fluid - the tissue water content increases as the protein content decreases. Long term repetitive joint use has been shown to lead to joint inflammation with associated joint pain and swelling, eventually leading to the loss of cartilage.

When the cause of the osteoarthritis is known, it is referred to as secondary osteoarthritis, caused by a particular disease or condition, such as obesity, trauma or surgery to the joints, or abnormal joints at birth.

Patients with osteoarthritis who take an active role in their own treatment can prevent additional joint damage and usually will be able to continue with most of their normal activities. The key to managing the condition is to get an accurate diagnosis and start early, proactive treatment. Most osteoarthritis treatments are focused on reducing the pain and inflammation associated with osteoarthritis and maintaining the joint mobility and flexibility needed to continue with necessary and desired activities. It is clear that a combination of proper exercise, joint mobility, weight control, nutrition and use of appropriate medication is required to control osteoarthritis.

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