Depending on whether the cause is known or not Osteoarthritis can be divided into :


I. Primary Osteoarthritis : In this type of osteoarthritis the cause is unknown but it is believed to be mainly related to aging. With the advancing age the water content of the cartilage increases which results in degeneration of the cartilage. Repeated use of joints through the years causes irritation of the cartilage causing joint pain and swelling. Osteoarthritis also tends to run in families indicating a genetic tendency.


II. Secondary Osteoarthritis : This type of osteoarthritis is secondary to some disease or condition. These may include:


  • Obesity :People who are 20% or more over their normal bodyweight tend to have more problem with their arthritis. Excess bodyweight puts an extra strain on the weight bearing joints (like knee, legs, feet)
  • Repeated trauma : Injury to the joint as may occur in sports like football / tennis.
  • Congenital abnormalities : Some people are born with abnormally formed joints that are vulnerable to mechanical wear, causing early degeneration and loss of joint cartilage like in Perthe’s disease, epiphyseal dysplasia, hip dysplasia (abnormal growth of tissue).
  • Inflammatory diseases like gout (crystal deposition in cartilage can cause it to degenerate), septic arthritis or rheumatoid arthritis.
  • Hormonal disorders like diabetes and growth hormone disorders (e.g. acromegaly) are also associated with early cartilage degeneration and secondary osteoarthritis.
  • Metabolic disorders like hemochromatosis in which a genetic abnormality leads to too much iron in the joints and other parts of the body.
  • Avascular necrosis where the blood supply to the bone near the joint is interrupted, leading to bone death and eventually joint damage.
  • Repeated episodes of bleeding into the joint, as may occur in hemophilia or related bleeding disorder.