Osteoarthritis and rheumatoid arthritis are the 2 most common types of arthritis.

Osteoarthritis

Osteoarthritis is the most common type of arthritis in the UK, affecting nearly 9 million people.

It most often develops in adults who are in their mid-40s or older.

It’s also more common in women and people with a family history of the condition.

But it can occur at any age as a result of an injury or be associated with other joint-related conditions, such as gout or rheumatoid arthritis.

Osteoarthritis initially affects the smooth cartilage lining of the joint. This makes movement more difficult than usual, leading to pain and stiffness.

Once the cartilage lining starts to roughen and thin out, the tendons and ligaments have to work harder.

This can cause swelling and the formation of bony spurs called osteophytes.

Severe loss of cartilage can lead to bone rubbing on bone, altering the shape of the joint and forcing the bones out of their normal position.

The most commonly affected joints are those in the:

• hands
• spine
• knees
• hips

Find out more about osteoarthritis

Rheumatoid arthritis

In the UK, rheumatoid arthritis affects more than 400,000 people.

It often starts when a person is between 40 and 50 years old. Women are 3 times more likely to be affected than men.

In rheumatoid arthritis, the body’s immune system targets affected joints, which leads to pain and swelling.

The outer covering (synovium) of the joint is the first place affected.

This can then spread across the joint, leading to further swelling and a change in the joint’s shape. This may cause the bone and cartilage to break down.

People with rheumatoid arthritis can also develop problems with other tissues and organs in their body.

Find out more about rheumatoid arthritis

Other types of arthritis and related conditions

• ankylosing spondylitis – a long-term inflammatory condition that mainly affects the bones, muscles and ligaments of the spine, leading to stiffness and joints fusing together. Other problems can include the swelling of tendons, eyes and large joints.
• cervical spondylosis – also known as degenerative osteoarthritis, cervical spondylitis affects the joints and bones in the neck, which can lead to pain and stiffness.
• fibromyalgia – causes pain in the body’s muscles, ligaments and tendons.
• lupus – an autoimmune condition that can affect many different organs and the body’s tissues.
• gout – a type of arthritis caused by too much uric acid in the body. This can be left in joints (usually affecting the big toe), but can develop in any joint. It causes intense pain, redness and swelling.
• psoriatic arthritis – an inflammatory joint condition that can affect people with psoriasis.
• enteropathic arthritis – a form of chronic inflammatory arthritis associated with inflammatory bowel disease (IBD), the 2 main types being ulcerative colitis and Crohn’s disease. About 1 in 5 people with Crohn’s disease or ulcerative colitis will develop enteropathic arthritis. The most common areas affected by inflammation are the peripheral (limb) joints and the spine.
• reactive arthritis – this can cause inflammation of the joints, eyes and the tube that urine passes through (urethra). It develops shortly after an infection of the bowel, genital tract or, less frequently, after a throat infection.
• secondary arthritis – a type of arthritis that can develop after a joint injury and sometimes occurs many years afterwards.
• polymyalgia rheumatica – a condition that almost always affects people over 50 years of age, where the immune system causes muscle pain and stiffness, usually across the shoulders and tops of the legs. It can also cause joint inflammation.