Primary Osteoarthritis eMedicine Orthopedics

Description: Osteoarthritis, the most common type of joint disease, is a heterogeneous group of conditions that result in common histopathologic and radiologic changes. It is a degenerative disorder that results from the biochemical breakdown of articular cartilage in the synovial joints. Although osteoarthritis is thought to be largely due to excessive wear and tear, secondary nonspecific inflammatory changes may also affect the joints.
Historically, osteoarthritis has been divided into primary and secondary forms, although this division is somewhat artificial. Secondary osteoarthritis is conceptually easier to understand. It refers to degenerative disease of the synovial joints that results from some predisposing condition, usually trauma, that has adversely altered the articular cartilage and/or subchondral bone of the affected joints. Secondary osteoarthritis often occurs in relatively young individuals. This form of the disease is beyond the scope of this article.
The definition of primary osteoarthritis is more nebulous. In the broadest sense of the term, primary osteoarthritis is an idiopathic phenomenon, occurring in previously intact joints, with no apparent initiating factor. Primary osteoarthritis is related to the aging process and typically occurs in older individuals. Some clinicians limit primary osteoarthritis to the joints of the hands (specifically the distal interphalangeal joints, proximal interphalangeal joints, and joints at the base of the thumb), whereas others include the knees, hips, spine (apophyseal articulations), and hands as potential sites of involvement. This article primarily focuses on osteoarthritis of the hand, knee, and hip joints.
Synonyms and related keywords: idiopathic osteoarthritis, degenerative joint disease, arthritis, secondary osteoarthritis
Stacy & Basu 2007