What's the difference between osteoarthritis and rheumatoid arthritis?

Forms of arthritis

Around 10 million UK adults are limited by the effects of arthritis in their day-to-day lives¹. Arthritis means inflammation of a joint. Your joints allow movement where two bones meet - including your fingers, elbows, knees, and hips - and so arthritis affects how you move, alongside other symptoms.

With more than 100 types of arthritis in existence, knowing how to spot the difference can help get you the right diagnosis and treatment.

The most common types of arthritis are:

• Osteoarthritis (OA).

• Rheumatoid arthritis (RA).

• Septic arthritis.

• Gout.

• Psoriatic arthritis (PsA).

Rheumatoid arthritis (RA) and Osteoarthritis (OA) are the two most common forms of arthritis². However, osteoarthritis is the most common by a long way, affecting around ten times as many people as rheumatoid arthritis.

The difference between osteoarthritis and rheumatoid arthritis

OA and RA may both cause joint pain, but they have many different characteristics. Here's how to tell them apart.

What's the cause?

OA: caused by wear and tear of joints.

The joining bones in your joints are coated in protective cartilage and a fluid called synovium which allows these bones to move together. In osteoarthritis, the movement between your bones wears these substances down over time. This gradually makes joints more painful and difficult to move.

RA: when your immune system attacks healthy tissue in your joints.

Your immune system mistakenly attacks the healthy synovium fluid that coats your joints. This causes inflammation in your joints, which can eventually lead to permanent damage, pain, and difficulty with movement.

Patient picks for Arthritis

Bones, joints and muscles

What causes osteoarthritis?

Osteoarthritis is the most common cause of arthritis, and typically affects older adults. It causes pain and stiffness of affected joints. Osteoarthritis typically affects the knees, hips, hands and spine, although it can affect other joints too. Diagnosing osteoarthritis is based on typical symptoms and examination findings. Tests like X-rays and blood tests often aren't needed, but can sometimes be useful to look for other conditions. Osteoarthritis treatments include maintaining a healthy weight, exercise, pain-relieving medication such as non-steroidal anti-inflammatory drugs (NSAIDs), and sometimes other treatments such as joint injections and surgery.

by Dr Doug McKechnie, MRCGP

Bones, joints and muscles

Chondrocalcinosis

Chondrocalcinosis is very common but only tends to cause symptoms when it is caused by an underlying condition, such as osteoarthritis.

by Dr Colin Tidy, MRCGP

Where in the body?

OA: usually affects one set of joints. It often begins on one side of your body but can spread to the other side. Osteoarthritis can affect any of your joints, but is most common in the ones that get used the most, such as your:

• Knees.

• Hips.

• Hands.

• Fingers and thumbs.

• Lower spine.

RA: usually affects joints that are parallel on both sides of your body and the smaller joints, such as those in your hands or your feet. Like osteoarthritis, any joint can be affected, but rheumatoid arthritis is most common in your:

• Fingers and thumbs.

• Wrists.

• Ankles.

• Feet.

RA may also affect your internal organs, including your:

• Heart.

• Liver.

• Eyes.

What are the symptoms?

Symptoms in your joints:

In osteoarthritis, there are no other symptoms outside of the joints. However, with rheumatoid arthritis, you may also experience other symptoms, including:

• Small painless lumps - usually over your forearms and elbows.

• Feeling tired all the time.

• A general feeling of being ill.

• A high temperature (fever).

• Unexplained weight loss.

• Muscle aches and pains.

What genetic and environmental factors?

OA is linked to:

• Joint injury or overuse.

• Age - most often develops in people over 50 years old, although secondary osteoarthritis, which is brought on by injury or damage, can occur in younger people.

• Sex - women are more likely to develop OA than men.

• Body weight - excess weight puts more stress on your joints, especially weight-bearing joints like your knees and hips.

• Genetics - having a family history of OA may make it more likely to develop it, although the risk is low.

RA is linked to:

• Never giving birth or never breastfeeding - puts women at greater risk than women who have.

• Smoking.

• Age - most often develops in people between 30 and 50 years old, but can affect people at any age.

• Sex - women are more likely to develop RA than men.

• Body weight - being obese increases your risk of RA.

• Genetics - there's evidence that RA can run in families.

How is it managed?

There is no cure for osteoarthritis or rheumatoid arthritis, so treatment for both aims to ease symptoms, make daily life more manageable, and prevent further joint damage where possible.

OA: Several lifestyle changes and therapies can help to improve symptoms. These include: regular physical activity that's gentle on joints, muscle-strengthening exercises to support joints, healthy weight loss, physiotherapy, prescription medications, over-the-counter pain relief drugs, and supportive equipment such as canes or crutches. If these treatments don’t make enough of a difference, your doctor may recommend surgery to replace your joints with artificial ones.

RA: special medications - called disease-modifying antirheumatic drugs (DMARDs) and biological response modifiers - may help slow the disease and prevent further joint damage. In addition to these drugs, people with rheumatoid arthritis can also self-manage their symptoms using many of the same therapies for osteoarthritis. Of these, healthy weight loss and regular, joint-protecting exercise are the most important.

Further reading

1. Arthritis Action: What is arthritis.

2. Centers for Disease Control and Prevention: Arthritis types.