Ouch! Your knee is super stiff, or both your hands feel like claws. What gives? If there's no injury, joint pain is usually due to either rheumatoid arthritis (RA), a systemic autoimmune disease in which an overactive immune system attacks healthy cells, or osteoarthritis (OA), a degenerative disease in which a particular joint is ground down by injury or overuse.

While the general consensus has always been that RA is more debilitating, a study published the September–October 2019 issue of Clinical and Experimental Rheumatology reported that “over the last 40 years, pain and functional disability in OA have appeared to be severe and similar to RA.”

Understand the Underlying Cause of Joint Pain

Getting relief may feel like the only thing that matters, but in the long run, the root cause of the pain is very important to determine. “The treatments for the two diseases are different,” says Paula Rackoff, MD, rheumatologist and clinical associate professor in the department of medicine at NYU Langone Medical Center in New York City. “You don’t want to miss the opportunity for reversing the inflammatory component of RA. And you don’t want to treat OA with potentially toxic medication if you don’t need it. But every RA patient eventually gets OA as well, so the pain needs to be diagnosed correctly and reassessed every time.”

Rheumatoid Arthritis vs. Osteoarthritis

“The pain and progression in each of the diseases are different. They can seem to be somewhat similar in that they both cause pain and decreased function. But then their similarities diverge,” says Mary Ann Wilmarth, doctor of physical therapy, a health and patient advocate and CEO of Back2back Wellness and a psoriatic arthritis and osteoarthritis patient.

Look for these differences:

Joint Pain Onset: What Did You Notice First?

RA It may be first noticed as tenderness and pain. If it lasts more than six weeks then you definitely want to seek medical care. If you have sudden onset of pain, redness, and swelling, this should be addressed right away. Often, the small joints in the hands and feet are affected first and equally on both sides.

RA is an autoimmune disease with inflammation. Many people experience fatigue and low-grade fevers. At times the fatigue may be one of the first things that a patient notices, either before or along with the joint pain. Some of the symptoms can wax and wane, including flares.

OA Osteoarthritis was long believed to be caused by the wearing down (“wear and tear”) of joints over time. But scientists now see it as a disease of the entire joint, involving the cartilage, joint lining (synovium), ligaments, and bone. OA is a common joint disease that affects from middle-aged (fifties) to elderly people, women more than men. OA joint pain can build up gradually over time. However, it can become worse after use — for example, after a hike.

Joint Pain: Where It Hurts Most

RA It can affect the entire body or just specific joints, most commonly the hands, wrists, fingers, elbows, knees, feet, and hips. Sometimes what is noticed first is the stiffness in the morning. The synovium, or the lining of the joint, is most affected.

OA It affects only a particular joint, and the pain doesn't go away without physical or medical therapy. The joint cartilage is what is worn away.

As OA progresses it can result in bony growths or spurs (osteophytes) that can further compromise joints (fingers). Sometimes you can have joints that make noise that can be painful (knees). It is also possible to get some radiating pain (hips).

Possible Additional Arthritis Symptoms

RA Fever, fatigue, hot rash, or joint swelling may occur. With RA, there is systemic inflammation. The eyes, lungs, and heart or circulatory system can also be affected by this inflammation, as well as the mouth and the skin with rheumatoid nodules. Patients with RA generally have a team of physicians to oversee their treatment of all this different systemic involvement.

OA The symptoms are focused on the specific joint(s) that are involved. Pain can be achy or sharp in nature and there may be radiating pain. OA symptoms can vary greatly among patients.

OA can make movement and exercise difficult at times. However, those are the exact things that are needed to assist with OA. If one does not exercise, that can contribute to obesity, which in turn contributes to load, systemic factors, and pain at various levels. The association between obesity and pain is well established, including its bidirectional nature, according to a study published in the April 1, 2021, issue of Osteoarthritis and Cartilage. According to the Arthritis Foundation, “losing 1 pound of weight resulted in 4 pounds of pressure being removed from the knees. In other words, losing just 10 pounds would relieve 40 pounds of pressure from your knees.”

The Location of the Joint Pain

RA Most commonly these joints are affected: hands, wrists, fingers, elbows, knees, feet, and hips. However, the pain can be in any joint. The pain is usually symmetrical — it effects both sides of the body at the same time.

OA There is pain wherever a joint has been injured or worn through overuse; most commonly in the hands, fingers, thumb, knees, hips, lower back and neck. The pain is not symmetrical. The lifetime risk of developing OA of the knee is about 46 percent, and the lifetime risk of developing OA of the hip is 25 percent, according to the American College of Rheumatology.

Morning Stiffness and Inflexibility

RA The stiffness takes 30 to 60 minutes or more to go away. There can be other joint stiffness during the day, but it is generally not as bad as the morning stiffness.

OA The stiffness generally loosens up within 30 minutes. Stiffness can occur after sitting or not moving for some time as well.

Diagnosis of Joint Pain Causes

RA Medical history, physical examination, imaging tests, and blood tests make up the process. The medical history is important because there can be a genetic component.

OA Medical history, physical examination, and imaging tests are used to determine diagnosis. Lab tests may also be done to rule out other forms of arthritis.

Different Types of Arthritis, Very Different Treatments

The goal of treatment for both is to improve movement, reduce pain, and minimize joint damage, but the way to that is different for each disease,” says Dr. Rackoff. Here's what to expect:

RA The first line of defense is using disease-modifying anti-rheumatic drugs (DMARDs) to reverse chronic inflammation. Anti-inflammatories, pain meds, and physical therapy are also used. It may take some time to determine which medication works optimally for your specific circumstances. A person may even need to try a few different types of medicine or a combination of medications. “ No two people, even with the same diagnoses, are alike in how they respond to various treatments. It’s a puzzle that has to be put together by you and your doctor,” says Dr. Wilmarth. It’s very important to keep an open and honest dialogue with your doctor(s) and healthcare team in general and especially in order to ideally reach and maintain remission with RA.

The goal with RA and other autoimmune illnesses is to treat to target (T2T). This sets remission or low disease activity as a goal. Patients are monitored frequently with their rheumatologist and adjustments to their treatment protocol are made as necessary.

OA Treatments include anti-inflammatories, pain meds, strength training, local steroid injections, and, in the worst cases, joint replacement surgery. Research is now being done on using collagen injections to rebuild cartilage. The American College of Rheumatology guidelines suggest that exercise should be one of the mainstays of treatment for osteoarthritis of the hip and knee.

Rheumatoid Arthritis vs. Osteoarthritis Joint Pain