What is Osteoarthritis?
This Common Joint Disease is Poorly Understood
Although the causes of osteoarthritis are not well understood, what is clear is that the disease is not due to wear and tear.
Despite being so common that it is almost universal in the middle-aged and elderly, osteoarthritis is a poorly understood disease. The medical profession, despite recent advances, still has only an incomplete grasp on the precise causes, whereas amongst the lay public, confusion is widespread.
This confusion is mainly due to the information given to sufferers by health professionals who, used to and, in some instances, still do, describe the disorder as 'wear and tear'. An analogy is often made to a mechanical joint which, after years of use, will eventually wear out.
This is poor analogy for two reasons. The joints of the body are not like a mechanical joint: they have a built-in repair mechanism and movement of the joint stimulates this repair. The other reason is that this comparison to a mechanical joint will discourage the sufferer from using the joint. Logic would suggest that if a joint is causing pain and stiffness because of wear and tear, then the sensible thing to do is to use it as little as possible. Unfortunately this is the worst thing to do with an osteoarthritic joint.
The Nature of Osteoarthritis
All of the body's tissues, including bone and cartilage, are constantly being replaced. Some tissues are turned over more quickly than others: blood for example is replaced in around 30 days, much more quickly than bone.
It's thought that this turnover mechanism goes wrong with certain joints in osteoarthritis. The cartilage of the joint is insufficiently built up and the remodelling of the normally smooth bone becomes chaotic with pitting and bony outgrowths. No one knows exactly why this happens but some factors predispose joints to the disease. These are: injury or deformity of the joint, age, gender – women more than men are affected, genetics, obesity – especially in relation to hip and knee osteoarthritis and certain physically demanding occupations.
Clinical Features
Some joints are affected more than others. The ankle joint, which bears considerable weight, is rarely affected unless previously injured, as is the shoulder. Most commonly affected are: hips, finger joints, knees and spine.
Pain in the affected joints is common, usually worse on movement. However some people with a considerable degree of osteoarthritis have little pain. Over time the joints become deformed; this is particularly noticeable in the fingers. Sometimes swelling and muscle wasting occurs.
Management
There is no cure for osteoarthritis but a number of things can be done to alleviate discomfort and reduce disability.
- Regular exercise: this keeps fluid circulating within the joint and helps strengthen surrounding muscles.
- Weight loss: Obesity is likely to exacerbate pain by increasing the load on the joint and reduce the amount of exercise taken.
- Physical therapy: massage and mobilisation of the affected joints can be helpful.
- Medication: Non-steroidal anti-inflammatory drugs are often prescribed, however these have side- effects. Paracetamol is the one recommended initially. In severe cases more potent medication is given.
- Injections: steroid injections into the joint can ease pain and restore mobility.
- Surgery: when the above have failed joint replacement surgery is undertaken.
- Supplements: there is some evidence that glucosamine can reduce pain and improve function. Side-effects are minor but some people have had allergic reactions. Many people feel that regularly taking cod liver oil helps relieve osteoarthritis.
This article is for information only. If you have any health concerns you should consult the appropriate health professional.
Resources:
ABC of Rheumatology ed .Michael Snaith. Pub. BMJ 2004
