Osteoarthritis vs. Rheumatoid Arthritis: What’s the Difference?
Key takeaways:
Rheumatoid arthritis (RA) and osteoarthritis (OA) can both cause joint pain and swelling. But they’re very different diseases.
RA is an inflammatory autoimmune disease that can affect other organs as well as your joints. OA is a degenerative process that only affects the joints.
OA and RA usually affect different joints. There are also key differences in lab tests, X-rays, and treatments.
Table of contents
“Arthritis” is a term you’ve probably heard before. But what does it mean? Arthritis refers to a disease that causes joint pain. The word comes from “arthro,” meaning joint, and “itis,” meaning inflammation. There are different types of arthritis. Rheumatoid arthritis (RA) and osteoarthritis (OA) are two common types.
RA and OA both cause pain and swelling in the joints. But they’re very different conditions. It’s important to know the difference because they have different complications and treatments. And proper treatment can slow down joint damage from arthritis.
What is rheumatoid arthritis?
Rheumatoid arthritis (RA) is an inflammatory condition that affects your joints and other organ systems. It’s an autoimmune disease. This means your own immune system causes the problem. This causes inflammation in your joints, leading to pain, swelling, and stiffness. Over time, it can cause irreversible joint damage.
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But RA can affect other areas of your body, too. Beyond joint pain, RA might start with fever, fatigue, achiness, and loss of appetite. Over time, it can affect other organs and blood vessels.
What is osteoarthritis?
Osteoarthritis (OA) is the most common type of arthritis. Like rheumatoid arthritis (RA), it damages your joints, causing pain and swelling. But OA is caused by the degeneration (breakdown) of cartilage in your joints — not an autoimmune process. This happens over time, usually starting in middle age. This is why people often describe it as the “wear and tear” of the joints.
But OA can also happen earlier in life. For example, a joint injury, like a meniscus tear, or joint overuse can speed up the damage. Inflammation is also possible when OA flares or worsens from time to time. But in this case, inflammation is a result of degeneration — not the cause of it. This can also lead to further joint breakdown.
What are the symptoms of rheumatoid arthritis vs. osteoarthritis?
Although rheumatoid (RA) and osteoarthritis (OA) are very different conditions, they also have some things in common.
Similarities
OA and RA are similar in that they:
Cause joint pain, swelling, and stiffness
Often affect the hands
Are more common in women
Can run in families
Can progress over time
Differences
There are some key differences between RA and OA that can help your healthcare team figure out the cause of your joint pain. This table highlights the key differences.
Rheumatoid arthritis (RA) | Osteoarthritis (OA) | |
|---|---|---|
Symptoms | Joint pain, stiffness, and swelling, especially in the morning Fatigue Fever Can affect other organs | Joint pain, stiffness, and swelling, which worsens after activity Symptoms limited to the joints |
Joints affected | Hands (knuckles and first joint in the fingers), wrists, and feet | Hands (second joint in the fingers), knees, hips, and back |
Symmetry | Affects joints on both sides of the body | Tends to start in only one joint, so both sides aren’t equally affected |
Cause | Inflammation due to autoimmunity | Breakdown of cartilage within the joint |
Treatments for RA vs. OA symptoms
Since rheumatoid arthritis (RA) and osteoarthritis (OA) have different causes, their treatments also differ. The good news is that treatment can help relieve your pain, prevent further joint damage, and optimize your mobility and function.
Did you know there are over 100 types of arthritis? Learn about the different types and categories.
Arthritis is the most common cause of joint pain. But it’s not the only one. If you have aching joints, it could be due to a few different reasons.
There’s a strong genetic component to arthritis. You might not be able to change your genes, but there are other steps you can take to protect your joints.
Treatment for RA starts with medications called disease modifying antirheumatic drugs, or DMARDs. These act on your immune system to prevent inflammation-related damage in your body. Without treatment, joint damage can greatly affect mobility and ability to take care of yourself. Treatments include:
Methotrexate
Biologic medications
Occupational or physical therapy
Joint replacement surgery (rarely)
Treatment for OA involves lessening the stress through the affected joint(s), preventing stiffness, and managing symptoms. This includes:
Anti-inflammatory medications (oral or topical)
Exercise and working to find a comfortable weight
Targeted strengthening of muscles around your joint
Joint replacement surgery
How do you know if you have RA or OA?
If you have joint pain, the best thing to do is to see your healthcare professional. They can help you figure out what’s going on with an evaluation that may include:
Reviewing your medical and family history (since arthritis and autoimmune diseases tend to run in the family)
Performing a physical examination of your joints
Ordering blood tests, which can be abnormal in rheumatoid arthritis (RA) but not in osteoarthritis (OA)
Ordering imaging tests
Can an X-ray show the difference between OA and RA?
Yes. Joints affected by RA look different than joints affected by OA. That’s why X-rays can help find the cause of joint pain. On an X-ray, there’s less space between the bones in OA. But in RA, the bone appears more eroded. That said, in the early stages of either condition, X-rays may still look normal.
Other imaging tests, like MRI, can also help. MRIs can offer more detailed images of the joints and can show joint inflammation. This can be especially helpful in the early stages of RA. So, your healthcare professional may suggest an MRI if you have RA symptoms but no evidence of arthritis on X-ray.
Can any other tests show the difference between OA and RA?
Yes. Depending on your symptoms, exam, and imaging results, a healthcare professional might also order blood tests. Since RA is an inflammatory autoimmune disease, there are certain markers that can help confirm the diagnosis. These include:
Autoantibodies, like rheumatoid factor and anti-cyclic citrullinated peptide antibody
Complete blood count (CBC)
C-reactive protein (CRP)
If you have swelling in a large joint, like your knee, a healthcare professional may also take a fluid sample for testing. This can also give clues to determine whether the cause is RA, OA, or something else.
What increases your risk for OA vs. RA?
There are factors that may increase your risk of rheumatoid arthritis (RA). These are:
Being over 50 years old
Having a family history of RA
Carrying a genetic trait linked to RA
Being born with female anatomy
Having excess body weight
There are also several things that can increase your risk for developing osteoarthritis (OA). These include:
Being over 50 years old
Overusing a joint or having a previous joint injury
Having a family history of OA
Being born with female anatomy
Having excess body weight
Frequently asked questions
Yes. It’s possible to have both OA and RA at the same time. In fact, having RA also makes you more likely to develop OA. That’s because the chronic inflammation caused by RA can lead to joint instability and cartilage damage. This increases your risk for OA over time. Keeping inflammation down and decreasing risk factors may help prevent OA in people with RA.
No. RA is an autoimmune process triggered by a combination of factors, while OA is caused by wear and tear. If you have OA and begin to have symptoms of RA, it’s best to see a healthcare professional for further evaluation.
Yes. A rheumatologist is a specialist in rheumatologic diseases that can affect your musculoskeletal system, like rheumatoid arthritis, lupus, and psoriatic arthritis. But other physicians can treat osteoarthritis, as well, including:
Family medicine doctors
Physiatrists (physical medicine and rehabilitation doctors)
The bottom line
Both rheumatoid arthritis (RA) and osteoarthritis (OA) cause joint pain, stiffness, and swelling. But they’re very different conditions with some unique features. They differ in symptoms, the parts of your body they affect, and how they damage your joints. If you have joint symptoms, your healthcare team can help you figure out whether RA, OA, or another condition is the cause.
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References
American Academy of Physical Medicine and Rehabilitation. (n.d.). What is a physiatrist?
American College of Rheumatology. (n.d.). Rheumatologist.
Lee, Y., et al. (2020). Patients with rheumatoid arthritis increased risk of developing osteoarthritis: A nationwide population-based cohort study in Taiwan. Frontiers in Medicine.
National Institute of Arthritis and Musculoskeletal and Skin Diseases. (2022). Rheumatoid arthritis. National Institutes of Health.
National Institute of Arthritis and Musculoskeletal and Skin Diseases. (2023). Osteoarthritis. National Institutes of Health.
Throckmorton, T. W. (2022). What is an orthopaedic surgeon? OrthoInfo.
