What is primary osteoarthritis (OA)?

Updated: Jun 10, 2020
  • Author: Carlos J Lozada, MD; Chief Editor: Herbert S Diamond, MD  more...
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Answer

The definition of primary osteoarthritis is more nebulous. Although this form of osteoarthritis is related to the aging process and typically occurs in older individuals, it is, in the broadest sense of the term, an idiopathic phenomenon, occurring in previously intact joints and having no apparent initiating factor.

Some clinicians limit the term primary osteoarthritis to the joints of the hands (specifically, the DIP and PIP joints and the joints at the base of the thumb). Others include the knees, hips, and spine (apophyseal articulations) as well.

As underlying causes of osteoarthritis are discovered, the term primary, or idiopathic, osteoarthritis may become obsolete. For instance, many investigators believe that most cases of primary osteoarthritis of the hip may, in fact, be due to subtle or even unrecognizable congenital or developmental defects.


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