Comparing Osteoarthritis & Rheumatoid Arthritis

Understanding How OA and RA Differ

Rheumatology, Eldery Person. Credit: BSIP / Contributor / Getty Images

Osteoarthritis (OA) is the most common type of arthritis. On the other hand, rheumatoid arthritis (RA) is recognized as the most crippling or disabling type of arthritis. What are the significant differences between osteoarthritis and rheumatoid arthritis?

How Do Osteoarthritis and Rheumatoid Arthritis Differ?

Osteoarthritis is also referred to as a degenerative joint disease or wear-and-tear arthritis.

It is caused by the breakdown of joint cartilage, a cushion between the bones that form a joint. Cartilage loss can cause a bone to rub on another bone in the joint — a condition that is very painful. Usually, osteoarthritis begins in a single joint.

Rheumatoid arthritis is a chronic, inflammatory type of arthritis and is also classified as an autoimmune disease. The synovium (lining of the joint) is primarily affected by rheumatoid arthritis, but organs body-wide can be affected as well. Multiple joints are usually involved with rheumatoid arthritis.

What Causes Each Arthritis?

Osteoarthritis is a joint disease which affects the cartilage. Scientific conclusions about its causes are evolving away from simply being wear-and-tear or the effects of aging. Water content of cartilage initially  increases while protein composition of cartilage steadily degenerates.

Other factors that may increase the risk of developing osteoarthritis include joint injury, repetitive use or stress of joints, being overweight, and family history/genetics.

With regard to rheumatoid arthritis, researchers have worked for years to find the cause of the abnormal autoimmune response associated with the disease. No single cause has been found. Common theories point to a genetic predisposition and a triggering event or events.

What Symptoms Point to One or the Other?

Osteoarthritis primarily affects the joints.

  • The most common symptom associated with osteoarthritis is pain in the affected joint after repetitive use or activity.
  • Morning stiffness lasts a half hour or less.
  • Joint pain is often worse later in the day.
  • The affected joint can also swell, feel warm, and become stiff after prolonged inactivity.
  • Bone spurs, bony enlargements (Heberden's nodes and Bouchard's nodes in the hands), and limited range of motion are also characteristics of osteoarthritis.

Rheumatoid arthritis symptoms include:

  • Joint pain
  • Joint swelling or effusion
  • Joint stiffness
  • Redness and/or warmth near the joint
  • Restricted range of motion
  • Morning stiffness lasting more than an hour
  • Involvement of the small joints of the hands and feet
  • Extreme fatigue
  • Rheumatoid nodules
  • Symmetrical joint involvement (both knees, not just one)
  • There also can be lung, kidney, or cardiac involvement.

How Are OA and RA Diagnosed?

This is where some similarities occur. X-rays of affected joints can show joint damage associated with osteoarthritis or rheumatoid arthritis. Arthrocentesis, joint fluid removal, and joint fluid analysis are possible procedures that can assess osteoarthritis or rheumatoid arthritis. The results differentiate which type of arthritis is involved.

Blood tests cannot definitively diagnose osteoarthritis, but may be used to rule out other conditions, including rheumatoid arthritis. Test results, a physical examination, and the patient's medical history together can help determine a diagnosis.

Laboratory tests which are commonly ordered to help diagnose rheumatoid arthritis include:

How Is Osteoarthritis Treated?

Treatment options for osteoarthritis focus on pain relief and restoring function to the affected joint. Medications are commonly used to treat osteoarthritis.

Nonsteroidal anti-inflammatory drugs (NSAIDs), analgesics, as well as steroid injections, are used to treat pain and inflammation.

Physical therapy that focuses on exercises to strengthen and stabilize the joint, support/bracing, heat, rest, and weight reduction are all important to a successful treatment regimen. Alternative treatments are used, such as massage therapy, acupuncture, and more.

And Rheumatoid Arthritis Treatment?

The primary treatment for rheumatoid arthritis is medication. There are five categories of medication commonly used to treat rheumatoid arthritis:

  • Biologics including Enbrel (etanercept), Remicade (infliximab), Humira (adalimumab), Rituxan (rituximab), Orencia (abatacept)
  • DMARDs (disease-modifying anti-rheumatic drugs) such as methotrexate
  • Corticosteroids such as prednisone, hydrocortisone
  • NSAIDs such as Celebrex (celecoxib) and naproxen
  • Analgesics (painkillers)

Along with medication, some forms of alternative and complementary treatment or local steroid injections may help relieve pain for rheumatoid arthritis.

For both rheumatoid arthritis and osteoarthritis, the last-resort treatment option is surgery. This includes arthroscopy, arthrodesis (fusion), and arthroplasty (joint replacement).

How Prevalent Are OA and RA?

Osteoarthritis affects over 27 million people in the United States and is most common in people older than age 65. All races in the U.S. appear to be affected equally by osteoarthritis. According to the American College of Rheumatology, 70 percent of people over the age of 70 have x-ray evidence of osteoarthritis.

Approximately 1.5 million people in the U.S. have rheumatoid arthritis, and about 1 to 2 percent of the world's population are affected by it. About 75 percent of rheumatoid arthritis patients are women. Men, women, and even children can develop rheumatoid arthritis, though.

Typically, disease onset for rheumatoid arthritis occurs between 30 and 60 years of age and the majority have no family history of it. When it occurs in men it usually strikes later in life.


Arthritis Foundation. Understanding Arthritis: Osteoarthritis

Arthritis Foundation. Understanding Arthritis: Rheumatoid Arthritis.


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