The Basics of Osteoarthritis
What Causes Osteoarthritis?
There are several factors that increase a person's chances of developing osteoarthritis. These include:
- Heredity. Some people have an inherited defect in one of the genes responsible for making cartilage. This causes defective cartilage, which leads to more rapid deterioration of joints. People born with joint abnormalities are more likely to develop osteoarthritis, and those born with an abnormality of the spine (such as scoliosis or curvature of the spine) are more likely to develop osteoarthritis of the spine.
- Obesity. Obesity increases the risk for osteoarthritis of the knee, hip, and spine. Maintaining ideal weight or losing excess weight may help prevent osteoarthritis of these areas or decrease the rate of progression once osteoarthritis is established.
- Injury. Injuries contribute to the development of osteoarthritis. For example, athletes who have knee-related injuries may be at higher risk of developing osteoarthritis of the knee. In addition, people who have had a severe back injury may be predisposed to develop osteoarthritis of the spine. People who have had a broken bone near a joint are prone to develop osteoarthritis in that joint.
- Joint overuse. Overuse of certain joints increases the risk of developing osteoarthritis. For example, people in jobs requiring repeated bending of the knee are at increased risk for developing osteoarthritis of the knee.
- Other diseases. People with rheumatoid arthritis, the second most common type of arthritis, are more likely to develop osteoarthritis. In addition, certain rare conditions, such as iron overload or excess growth hormone, increase the chance of developing OA.
How Is Osteoarthritis Diagnosed?
The diagnosis of osteoarthritis is based on a combination of the following factors:
- Your description of symptoms
- The location and pattern of pain
- Physical exam
Your doctor may use X-rays to help confirm the diagnosis and make sure you don't have another type of arthritis. X-rays show how much joint damage has occurred. An MRI may be necessary to get a better look at the joint and surrounding tissues if the X-ray results do not clearly point to arthritis or another condition.
Sometimes, blood tests will be performed to determine if you have a different type of arthritis.
If fluid has accumulated in the joints, your doctor may remove some of the fluid (called joint aspiration) for examination under a microscope to rule out other diseases.