There are an estimated 10 million people with some form of arthritis in the UK. It is the most common cause of disability in the UK and can affect people of all ages, not just older people.
Arthritis means literally ‘inflammation of the joints’. Inflammation is a difficult thing to imagine and describe, but it is part of the body’s normal healing process after injury, just like the healing of a cut or bruise. If inflammation in the joints becomes extreme, it can cause pain, stiffness and swelling.
The most common type of arthritis is osteoarthritis, more usually known as “wear and tear” or degenerative arthritis which often affects people as they get older. The next most common types of arthritis are rheumatoid arthritis where the immune system attacks the joints and gout which is caused by uric acid crystals in the joints. Rheumatoid arthritis and gout are two types of “inflammatory arthritis” but there are many other forms of inflammatory arthritis including psoriatic arthritis and ankylosing spondylitis.
In a normal joint, two bones are connected and supported by ligaments and covered by muscles and tendons which move the joint. Inside the joint is a small amount of synovial fluid which helps lubricate the joint and help the joint to move. There are also cartilages inside the joint which act as shock absorbers.
In a joint with osteoarthritis, there is thinning of the cartilage, bony outgrowths from the sides of the joint, increased amounts of fluid inside the joint and some fragments of worn cartilage inside the joint. This can all cause pain, swelling and disability.
What causes arthritis?
As there are so many different types of arthritis, there is no one cause of arthritis but the following factors may be important.
- Genetics – arthritis can sometimes run in families, especially rheumatoid arthritis and osteoarthritis of the fingers
- Gender – some types of arthritis are more commonly found in women and some in men
- Age – osteoarthritis is usually a problem in later life whereas other types of arthritis such as rheumatoid arthritis and ankylosing spondylitis commonly start in young adults
- Injury – damage to a joint for example a broken bone or a football injury can cause osteoarthritis later in life
- Infections – certain viral and other infections can trigger some types of arthritis
- Lifestyle – osteoarthritis is more common in the overweight and alcohol can trigger gout. Smoking is more common in people who develop rheumatoid arthritis