What causes osteoarthritis?
The exact cause isn't known. Osteoarthritis may be hereditary, which means it runs in families. Osteoarthritis seems to be related to the wear and tear put on joints over the years in most people. But wear and tear alone don't cause osteoarthritis.
What happens when a joint is affected?
Normally, a smooth layer of cartilage acts as a pad between the bones of a joint. Cartilage helps the joint move easily and comfortably. In some people, the cartilage thins as the joints are used. This is the start of osteoarthritis. Over time, the cartilage wears away and the bones may rub against one another.
Bones may even start to grow too thick on the ends where they meet to make a joint, and bits of cartilage may loosen and get in the way of movement. This can cause pain, joint swelling and stiffness.
Who gets osteoarthritis?
Osteoarthritis is more common in older people because they have been using their joints longer. Using the joints to do the same task over and over or simply using them over time can make osteoarthritis worse.
Younger people can also get osteoarthritis. Athletes are at risk because they use their joints so much. People who have jobs that require the same movement over and over are also at risk. Injuries to a joint can increase the risk of arthritis in the joint later on. Excess weight also can accelerate arthritis in the knees, hips and spine.
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Written by familydoctor.org editorial staff