Osteoarthritis (OA) is the most common form of arthritis, with millions of people worldwide affected by this crippling disease. The extent of the disease burden has not been well determined in South Africa, but the National Arthritis Foundation in the USA reports that one in five people over the age of 18 have OA.

"Although this disease has been largely attributed to 'wear and tear' or degenerative disease, newer studies suggest that obesity - which is a risk factor for OA - may cause OA resulting from the discharge of substances released from fatty tissue which cause inflammation," said Dr Mou Manie, Head of the Division of Rheumatology at Stellenbosch University's Faculty of Medicine and Health Sciences.

The disease affects people differently, with joint damage developing over years or in some cases more quickly. It can have a negative influence on the patient's physical well-being, as well as an adverse effect on lifestyle and finances.

Dr Manie answered the most frequently asked questions about this disease.

Osteoarthritis (OA) – FAQ`s

1.    What is OA?

Arthritis is a term meaning inflammation of a joint or joints. OA is a form of arthritis resulting from degeneration of the protective cartilage which lines the ends of the bones around the joint.

2.    How common is OA?

It is the most common form of arthritis. The onset is typically in the fifth decade of life and it progressively affects increasing numbers of people, so that by the age of 70 years most individuals will be affected by this disease.

With increasing numbers of people living to an older age, OA is likely to be an important contributor to the burden of disease affecting the musculoskeletal system.

3.    Why should members of the public and organisations know about OA?

OA comes in various guises and many people have the condition without knowing about it. Not only is OA the most common form of arthritis, but it is also is an important contributor to the global burden of disease. In a study done in Cape Town it was found that one of the forms of OA, namely mechanical backache, was a very common cause of sick leave, thus having an adverse effect on the economy of the country.

4.    Which joints are affected by OA?

The joints typically affected are the hands, where the distal and proximal (front and back) finger joints and the base of the thumb are affected. Other joint areas affected include the knees, hips, base of the big toe, lower cervical spine and lower lumbar spine.

5.    What are the risk factors for developing OA?

The well-known predisposing factors for OA are:

• Age.
• Gender – females are more commonly affected than males.
• Genetic – the nodal (bump) form affecting mainly the hands (see below), tends to run in families. In contrast, in the form of disease which affects the weight bearing joints such as the knee and hip, the genetic component is not that strong.
• Obesity – this is thought to be the result of weight bearing and strain, especially of the knee joint.
• Previous joint damage, particularly of the cartilage. Typical examples of these include:
• Trauma.
• The presence of joint diseases such as rheumatoid arthritis and gout.
• Abnormalities of the underlying cartilage caused by other illnesses such as Perthes' disease.
  
   

6.    How does one distinguish between OA and other forms of arthritis such as rheumatoid arthritis (RA) and gout?

The main distinguishing features are the distribution of the joints affected and the nature of the pain. In OA the pain is typically made worse by activity, whereas in RA the pain is relieved by activity. In OA, the hands are affected, but the disease generally spares the wrist and elbows, whereas with RA the joint involvement is often more widespread and the associated morning stiffness is often more prolonged. In gout, the onset is characteristically more acute and is not an uncommon cause of a single very painful and swollen joint. It is also not uncommon for OA to occur in a patient with gout and vice versa.
 

7.    How is OA treated?

There is no cure for OA and therapy consists mainly of medication such as paracetamol, ibuprofen or diclofenac, which relieves pain and inflammation. In those patients with nodal OA of the hands, disease modifying therapy like chloroquine may result in relief of the severe pain and inflammation that some patients experience.

Topical applications such as methyl salicylate ointment have been shown to be of benefit. A more recently launched complementary topical gel called Flexiseq has shown some promise.

Evidence is lacking that over the counter therapies such as glucosamine and chondroitin works, but some patients report relief of symptoms. In cases where a single joint is involved, for example those with OA of the knee, physiotherapy and weight reduction may be of value. In very severe cases surgery, such as a knee or a hip replacement, may be necessary.

8.    Are there any new developments or novel ideas in the field of OA?

Despite extensive research internationally, the search for more options, including the use of biologic agents (genetically-engineered proteins derived from human genes) for changing the course of the disease, has not yielded convincing results.

Of interest is that whereas OA has been thought to be a largely "wear and tear" or degenerative disease, newer studies suggest that obesity - which is a risk factor for OA - may cause OA resulting from the release of substances released from fatty tissue which cause inflammation.

Newer studies also suggest that although the primary target for joint damage is the cartilage lining the joints, other factors such as bony abnormalities and altered pain perception may also be involved in the aetiology of OA.

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Faculty of Medicine and Health Sciences     
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