It is a wear-and-tear disorder of the major joints, including the hips, knees, spine and fingers.
The most commonly affected joint is the hip. If you perform X-rays on people over 65, you will find around one in 20 has evidence of wear and tear in their hip joint and it is a significant cause of disability in older people.
The second most common problem area is the knee, and the finger and thumb joints are often affected too, making it painful and difficult to carry out the simplest of household tasks.
So how likely are you to develop osteoarthritis? As it is a condition primarily caused by wear and tear, with the cartilage between the joints gradually being worn away, the risks do increase the older you get.
But we also know that there is a genetic predisposition for the condition, and that it often runs in families, being passed down from generation to generation.
Weight is a factor in osteoarthritis of the knees and, interestingly, the fingers, but not the hips.
The condition is more common in people who have damaged the joints, while playing sports for instance. There is also a link with jobs involving a great deal of heavy lifting or prolonged standing.
Once you have developed osteoarthritis it is not necessarily always a downhill path, with increasing pain as the joints degenerate. Some patients can see an improvement while others might remain stable for many years.
But in a substantial number of cases, the joints will deteriorate to the point at which orthopaedic surgery becomes the best option.
For the right patient - with the right surgeon - surgery can give fantastic results. But for some suffering with osteoarthritis, pain relief is the immediate priority and thankfully there are a number of options, including analgesics, such as paracetemol and codeine, and non-steroidal anti-inflammatories.
Some people find using a cream containing capsaicin, the active component that gives chilli peppers their heat, helps.
Others find relief in other sources of heat, but they need to be careful not to cause serious damage to the skin or blood vessels by, for example, sitting too close to a fire for hours on end.
There is also a wide range of preventative remedies on the market such as glucosamine. For most sufferers, there is no particular evidence that they work. However, some people swear by them, and as they do no harm, I am happy for patients to take them.
There is evidence, however, that taking regular doses of vitamin D is important. This is especially so in Britain, where during the winter months, huge numbers of people suffer vitamin-D deficiency through lack of exposure to sunlight, potentially causing muscle and joint pain. In London, 70 per cent of people do not generate sufficient vitamin D during the winter.
Sadly, there is no wonder drug on the market for osteoarthritis. Great claims have been made for some which have offered short-term improvements in pain levels, only for them to turn out to cause considerable damage to the joints.
Other causes of arthritis, though, can be successfully controlled with drugs. Rheumatoid arthritis, an inflammatory version of the condition, can affect any organ of the body, although it is the joints that take the main hit.
With early diagnosis and treatment, drugs can "turn the disease off", preventing destruction of the joints.
There are also successful treatments which can be used in another big cause of arthritis among older people - gout. This is a condition often associated with over-indulgence, and although you do not have to be a big eater or drinker to get gout, if you are predisposed to it, cutting down on red meat or beer and spirits will reduce your chances of an attack.
There are also effective drugs both to tackle acute attacks and to keep it at bay in the longer term.
For older people, one of the biggest risks to their health are falls, especially as many are more vulnerable to fractures because of osteoporosis, or lower bone density.
Every year, about one-third of over 65-year-olds and more than half of over 80-year-olds suffer falls. Falls are the leading cause of injury and death for older people. That is why it is so important to keep your fitness up in later life. The fitter you are, the stronger your muscles are and the less likely you are to fall and so the less likely you are to develop fractures.
And more widely, that is the message for so many of the conditions that cause arthritis. Keeping your weight down, staying fit, and taking exercise to build muscle tone really help, thereby taking the pressure off the joints and helping to prevent further decline.
You are never too old or too infirm to take some sort of exercise and it really is a positive way forward to help you stop getting "old" as you get older.
