Chang-Miller M.D. April - Mayo Clinic on Arthritis

O steoarthritis is the most common form of arthritis, especially in older adults. Often called wear-and-tear arthritis, it occurs when the protective cartilage that cushions the ends of bones in your joints deteriorates.

With use, the soft, pliable layer of cartilage may start to wear down and its smooth surface roughens. At this point many people feel intermittent pain in the joint, especially after strenuous use.

If the cartilage wears away completely, you may be left with bone rubbing on bone, which damages the ends of your bones. This is usually painful.

The condition gradually worsens over time, and no cure exists. But treatment can slow progression of the disease, relieve pain and improve joint function.

In this chapter, youll learn about osteoarthritis, its signs and symptoms, and how its diagnosed and treated. There are other conditions, including back pain, bursitis and tendinitis, that at least initially may be confused with osteoarthritis youll find information about these related conditions as well.

If you have osteoarthritis, your joints may be stiff and achy when you get out of bed in the morning but feel less creaky soon after, about the time you finish the first cup of coffee. Your fingers may be stiff and deformed, making it hard to hold a pen or open a jar. Your knees may start to ache after a game of tennis or a jog in the park.

Osteoarthritis, sometimes called degenerative arthritis or degenerative joint disease, affects approximately 27 million American adults. The disease is more common in women than in men.

The condition may affect any joint in your body, but it most often occurs in the hands, knees, hips and back. Initially, osteoarthritis tends to affect only one joint but then spreads. For example, you may first feel pain and stiffness in the index finger of one hand, but eventually multiple finger joints in both hands may be affected.

Your body tries to repair the damage, but the repairs are usually inadequate. When protective cartilage in the joint wears away, new bone growth forms spurs (osteophytes) along the sides of existing bones. Prominent lumps that can form around the joint as a result occur most often with osteoarthritis of the hands and feet. Pain and tenderness over the bony lumps may be most noticeable early in the disease and less noticeable later on.

If cartilage in a joint is severely damaged, the joint lining (synovium), also called the synovial membrane, may become inflamed. A low-grade inflammation (synovitis) can cause episodes of joint swelling.

Some scientists believe cartilage damage may be due to an enzyme imbalance in the cartilage cells or lining of the joint. When balanced, these enzymes allow for the natural breakdown and regeneration of cartilage. But too many enzymes can cause the cartilage to break down faster than its rebuilt. The exact cause of this enzyme imbalance is unclear.

Early changes to the cartilage and bone dont always result in pain or other symptoms. Many older adults have osteoarthritis but are unaware of it until their doctor sees it on a routine X-ray.

The risk of osteoarthritis increases with age, with the disease most often developing after age 40. Its relatively rare among younger adults unless theyve had a joint injury. Those affected often have a family history of the disease.

Although an active lifestyle may slow the development of osteoarthritis, almost everyone older than age 65 will experience some joint damage and have mild symptoms. Men usually develop symptoms before age 55, while women typically dont have symptoms until after that age.

A severe injury to one or more joints at an early age may lead to osteoarthritis years later. Also, excessively stressful use of joints over many years such as working at a job that requires repeated knee bending may cause osteoarthritis later on. If certain activities are causing joint pain, avoid those activities until youve had the joint examined by a doctor.

Being overweight also increases your risk of developing osteoarthritis, especially in the hips and knees. In one study, women who were heaviest were twice as likely to get osteoarthritis and had three times the risk of knee osteoarthritis. Losing excess weight can help you reduce that risk. ()

A. (left) The first signs of osteoarthritis in a joint are microscopic pits and fissures on the surface of cartilage, which are usually accompanied by mild inflammation.

B. (right) As the cartilage is worn completely through, the contours of the joint are changed and patches of exposed bone appear.

C. (left) The subsurface bone thickens and spurs (osteophytes) develop. Using the joint causes pain.

D. (right) In advanced stages of osteoarthritis, the space between bones may disappear and ligaments loosen, causing further joint instability. The irregular surface of bones can cause marked limitation of motion.

Signs and symptoms

Osteoarthritis symptoms usually develop slowly and worsen over time. At first, many people notice pain and stiffness after a bout of strenuous activity or when first getting up in the morning. The morning stiffness associated with osteoarthritis usually passes in less than 30 minutes, a phenomenon called gelling.

If you have osteoarthritis, you may experience:

• Joint pain or tenderness during or after use, or following a period of inactivity
• Joint discomfort before or during a change in the weather
• Joint swelling and stiffness, particularly after use
• Formation of bony lumps on the middle or end finger joints or at the base of the thumb
• Loss of joint flexibility
• Grating sensation in the joint

Elastic structures called disks cushion the vertebrae in a normal spine, keeping the spine flexible. In osteoarthritis, disks may narrow and bone spurs form. Pain and stiffness may occur where bone surfaces rub together, and the spine becomes less flexible.

Be aware that the normal wear and tear on your joints doesnt necessarily result in osteoarthritis. Also, realize that osteoarthritis isnt an inevitable part of aging. But, if you get the condition, the symptoms dont go away. Pain tends to increase over the years and, progressively, limits your activity.

Osteoarthritis commonly occurs in the neck or back. The cartilage disks that cushion the vertebrae of your spine can wear down. When this happens, spaces between the bones narrow and bony outgrowths called spurs may form. When bone surfaces rub together, the affected areas of the vertebrae become inflamed, causing stiffness and pain. Gradually, your spine stiffens and loses flexibility. If several disks are involved, you may notice a loss of height.

Spinal stenosis is a condition associated with osteoarthritis of the spine. Spinal stenosis occurs when degenerating disks and bone spurs bulge into the spinal canal and press on the spinal cord or on nerve roots where they exit the spine between the vertebrae. This is commonly referred to a pinched nerve You may feel pain in your neck, shoulders, arms, lower back or even legs. (.)