The Basic Facts of Osteoarthritis

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Osteoarthritis, also referred to as degenerative joint disease, DJD, or wear-and-tear arthritis, is the most common form of arthritis and is caused by the breakdown of cartilage in one or more joints. Cartilage acts as a cushion between the bones of joints. When there is cartilage loss, a joint can become bone-on-bone, which is very painful for the patient.


Osteoarthritis which is considered "primary" is mostly a consequence of aging. Water content of cartilage increases while protein composition of cartilage degenerates. Besides aging, factors which may increase the risk of developing osteoarthritis include:

  • injury to joints
  • repetitive use of joints
  • being overweight
  • stressing the joints
  • family history

Secondary osteoarthritis can develop as a consequence of another disease or condition.


Osteoarthritis predominantly affects the joints, unlike other types of arthritis which may have systemic effects. The most common symptom associated with osteoarthritis is pain in the affected joint after repeated use. Joint pain is often worse later in the day. The affected joints can swell, feel warm, and become stiff after prolonged inactivity. Osteoarthritis can occur with other forms of arthritis simultaneously. Bone spurs and bony enlargements (nodes) are also characteristic of osteoarthritis.


X-rays of affected joints can show joint damage associated with osteoarthritis (i.e. cartilage loss, narrowing of joint space, bone spurs).

Blood tests are not used to diagnose osteoarthritis but may be used to rule out other conditions. Arthrocentesis, joint fluid removal, and joint fluid analysis are possible procedures to assess osteoarthritis. If necessary, arthroscopy, a surgical technique can allow doctors to visualize the joint space and abnormalities which can possibly be repaired.


Treatment options for osteoarthritis focus on pain relief and restoring function to the affected joint. Physical treatments include weight reduction, exercise, supports, heat, and rest. Medications include topical, oral, or injectible formulations to relieve pain and inflammation. There are also alternative treatments, including dietary supplements, massage therapy, acupuncture, and more. Surgical treatments are typically last-resort options.


Osteoarthritis is a common condition associated with aging.

  • Osteoarthritis affects over 27 million people in the United States.
  • Osteoarthritis occurs more frequently in males before age 45.
  • After age 55, osteoarthritis occurs more frequently in females.
  • All races in the United States appear to be affected equally.

According to the American College of Rheumatology, 70 percent of people over the age of 70 have x-ray evidence of osteoarthritis.

Points of Interest

Maintaining healthy weight is important. According to the Arthritis Foundation, for every pound of weight lost, there is a four-pound reduction in the load exerted on the knee for each step taken.

Another interesting fact concerns the correlation between level of pain and visible damage on x-rays. It's possible for a patient to have a lot of joint damage on x-ray yet have minimal symptoms. Conversely, a patient may have a lot of pain but not much damage observed on x-ray.

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Article Sources
  • Osteoarthritis - American College of Rheumatology
  • Osteoarthritis Fact Sheet - Arthritis Foundation