The pain and stiffness of osteoarthritis occurs because osteoarthritis damages the surfaces of our joints, so they don’t move smoothly against one another, as they would do normally.
What causes osteoarthritis?
In the course of our lives our joints can become damaged, through injury genetics, age and other causes. Our bodies can usually repair the damage and most of the time we aren’t aware that anything has happened. But when we have osteoarthritis, our bodies can’t fully repair the problem, and we can end up with swollen, painful joints.
Osteoarthritis happens when some of the cartilage that overlaps each end of the bones, becomes rougher and thinner as time goes on. At the same time the bone underneath the cartilage gradually becomes thicker. While this is going on the tissues in your joint change in different ways, as if they are trying to help repair the damage.
- The outer edges of the bones in the affected joints grow outwards. The protruding bony spurs you end up with are known as osteophytes.
- The inner layer of the capsule that surrounds your joint is called the synovium. When you have osteoarthritis this may become thicker, and can produce extra synovial fluid. The fluid is important to help keep your joint working properly, but extra fluid makes your joints swell.
- The capsule itself, and the ligaments – the strong bands that hold the joint together, thicken and contract.
Read our guide to taking care of your joints
Osteoarthritis causes symptoms well known to doctors who specialise in osteoarthritis. They include:
- Stiff joints, especially when you haven’t moved for a while, but which can ease once you start moving
- Pain in the affected joints
- Swelling which may feel soft, when caused by extra synovial fluid, or hard, when caused by the bony spurs, osteophytes.
- Grinding or grating feelings, also known as crepitus – your joints creaking when you move.
- Restricted joint movement – with osteoarthritis your joint may not allow your leg or arm to move as far as usual. Muscle strengthening exercises can help with this.
- Muscle thinning around your affected joint
Your symptoms won’t stay the same all the time, they can vary, and you won’t always know why. The weather can make a difference, and you may find that your pain is worse if you’ve been doing more exercise than usual
Read our guide to expert help for osteoarthritis
Types of arthritis
There are different types of arthritis – a term that doctors use when you have inflamed joints - including rheumatoid arthritis, ankylosing spondylitis (AS) which mostly affects your back, and gout, but osteoarthritis is the most common type in the UK.
Osteoarthritis can affect any joint in the human body, and any joint that has been injured or operated on is more likely to be affected.
The most common sites affected by osteoarthritis are your knees, hips, neck and back, big toes, and hands.
Risk factors for osteoarthritis
Age is a factor – osteoarthritis becomes more common as you get older. It usually starts in people in their late 40s or older. It is more common in women, and tends to be more severe than it is in men.
Being overweight or obese means you’re more likely to develop osteoarthritis, especially in your knees. It also means you’re at greater risk of the condition becoming worse with time.
Other factors increasing your likelihood of developing this condition include having joint injuries or an operation on a joint, having joint abnormalities, and inheriting genes that are linked to osteoarthritis.
Aching joints? Find out what could be the cause
When it comes to diagnosing osteoarthritis, your doctor will look for these symptoms (as above);
- Stiff or tender joints
- Pain in the affected joints
- Grinding or grating feelings and sounds (crepitus)
- Restricted joint movement and/or joint instability
- Thinning muscles
Tests for osteoarthritis
Your doctor may also carry out tests to check for osteoporosis, however, you may not need one if your symptoms are clear enough evidence.
The most useful test when checking for osteoporosis, are X-rays. They may be able to show that the space between your bones at your knee and other joints has narrowed.
In some cases a magnetic resonance imaging scan (MRI) can be useful – for instance it can let your doctor see joint problems that aren’t among the usual osteoarthritis symptoms.
What can you do to help yourself? Read our guide to lifestyle changes for osteoarthritis