Arthritis is an umbrella term for various conditions that cause joint pain, including osteoarthritis, inflammatory arthritis, posttraumatic arthritis, and septic (infectious) arthritis.

The most common type of arthritis is osteoarthritis, which is sometimes called 'wear and tear' arthritis, referring to age-related cartilage loss.

There is no cure for arthritis, which includes more than 100 separate joint pain and stiffness conditions.

Diagnosis and treatment of hip and knee osteoarthritis

Osteoarthritis is the most common type of arthritis, resulting from age-related degeneration of the soft cartilage lining between bones. As this layer breaks down, the normal smooth motion between bones is lost and the joint becomes painful.

Arthritis affects almost 60 million Americans, with about 1 in 5 US adults developing this type of joint pain as they age.

Explore the basics of arthritis in this 1440 Original video with orthopedic surgeon Dr. Nick Golinvaux.

Five advancements in arthritis research

It is estimated that nearly 350 million people worldwide are currently suffering from arthritis. This resource explores five of the most promising recent advancements in arthritis research as scientists work towards improved treatments and continue the search for a cure.

Rheumatoid arthritis occurs when the immune system attacks cells within joints.

Watch real knee surgery footage to see what arthritis looks like up close.

Visualizing a joint under attack from rheumatoid arthritis

A particularly difficult arthritis subtype is rheumatoid arthritis, a painful condition provoking a vicious cycle of joint inflammation, destruction, and dysfunction. It begins with a misfiring of the patient’s own immune system—for unknown reasons, it identifies joint and cartilage cells as foreign, initiating an attack to eliminate the supposed "invaders."

Rheumatoid arthritis affects about 1% of the population

Rheumatoid arthritis is an autoimmune condition leading to breakdown and inflammation of multiple joints throughout the body. This academic article provides an updated deep dive into our current cellular understanding of rheumatoid arthritis, how it is diagnosed, and the variety of medications available for treating this painful condition.

Researchers are investigating how altering the gut microbiome may influence the development of rheumatoid arthritis, which is an autoimmune disease.

A human joint is any place in the human body where two bones connect, providing structure and stability.

Limb regeneration research may lead to treatments for arthritis

For scientists pursuing the cure for arthritis, the holy grail of discoveries lies in how to regrow healthy cartilage inside human joints. While this feat has so far resisted our best scientific attempts, there are plenty of other human tissues—such as the liver and fingertips—that will successfully regenerate.

Impressionist painter Pierre-Auguste Renoir suffered from arthritis in the 1800s when there were no treatments, and eventually had such limited hand function that he painted with brushes placed in his mouth.

Inflammaging is chronic low-level inflammation as we age, and it may be a key disease driver

The term refers to the idea that largely invisible but consistent low-level inflammation as humans age fuels chronic diseases and cellular aging. Inflammaging, this article says, is due to lifestyle factors like poor sleep, low levels of activity, and poor diet, acting in concert to cause cellular damage and trigger inflammation.

More than 5 million Americans have more than one autoimmune disease

Overall, about 4.6% of the US population—15 million people—have an autoimmune condition. Some common examples include rheumatoid arthritis, psoriasis, type 1 diabetes, Grave's disease, and autoimmune thyroiditis.

Autoimmunity is when the body attacks itself, causing inflammation

Inflammation is the body's way of healing itself, and acute inflammation saves our lives when we have injuries or infections. It increases blood flow to the affected areas to bring immune cells to fight off invaders. This often results in short-term swelling, redness, and pain.

Kangaroos evolved exceptionally thick knee cartilage to absorb shock, and scientists are studying the animals for potential insights about how to safeguard human knees against arthritis.

Learn about the point of the physical and emotional experience of pain, which has three broad categories that help determine treatment approaches.

Skull bone marrow may be playing a key role in chronic pain.

See the anatomy of a healthy knee joint, which has smooth cartilage that cushions the joints and protects the bones from rubbing together.

Breaking down the knee's anatomy

The human knee is a remarkably complex structure carrying the full weight of the body throughout a person's life while allowing a number of complex twists, flexes, and extensions. It's also one of the body's biggest weaknesses—the location of chronic pain and replacement surgeries for millions of Americans.

What is Archaeology?

If you are up-to-date on your Jurassic Park lore, then you likely already know the answer to this question. But for those of us who didn't delve into the world in dinosaurs, it's easy to assume that professionals who study old stuff likely study the remains of what came before us, right? Find out in this article by the Society for American Archaeology.

Learn about the more than 100 known autoimmune diseases

Explore this resource with summaries and related resources for the dozens of autoimmune diseases defined in the medical literature. Many of these disease write-ups also have interviews with a patient with the disorder—offering a personal take about challenges, advice, and lifestyle effects.

Many patients with psoriasis develop other autoimmune diseases, too

A small study published in 2024 found that nearly three-quarters of patients with psoriasis—a condition in which the body attacks healthy skin cells—also developed autoimmune disorders including thyroid diseases, connective tissue diseases, and more, suggesting such connections between these autoimmune disorders warrant further exploration.

The collapse of gas bubbles in the joint synovial fluid causes 'cracking' knuckles.

Over 28% of US adults use yoga for pain management.

Autoimmune diseases affect between 5% and 10% of people worldwide, but their causes remain unknown

Autoantibodies—which attack the body—may be detectable in the body years before a patient develops symptoms, but some people may have detectable levels yet never go on to develop an autoimmune disease. This video discusses this and other unsolved mysteries with autoimmune disease.

Alzheimer's disease is the leading cause of dementia and risks rise after age 65

Read this primer about Alzheimer's disease and learn what factors increase the risk of this form of dementia, including genetics, being a woman, and health conditions, including high blood pressure.

Dementia describes progressive memory issues that impact daily activities

Although Alzheimer's disease is sometimes thought of synonymously with dementia, there are multiple types of dementia, which manifest in memory loss and other symptoms that make it challenging to perform daily tasks. These types include Lewy Body dementia, vascular dementia, and frontotemporal dementia. Parkinson's disease is not a form of dementia, but this movement disorder can sometimes develop into issues with memory and a formal diagnosis of dementia.

Explore this 1440 Original video offering a primer on Alzheimer's disease and what's known about its incidence, causes, and more.

There's no specific anti-inflammatory diet, but certain foods increase the chance of inflammation

Research suggests humans can reduce inflammation by limiting foods that are already known to be unhealthy for the human body—because they alter gut bacteria and stress the immune system—such as highly-processed foods, deep fried foods, sugary drinks, trans fats, red meats, and foods made with white flour. Foods that help the body include fatty fish such as salmon, legumes, fruits, and vegetables.

Dinosaurs suffered from cancer, arthritis, and infections seen in modern animals

Using CT scans and advanced pathology techniques, paleopathologists have identified respiratory illnesses, malignant osteosarcoma, and other diseases in dinosaurs. The research has helped show how many of these ailments are not exclusively modern phenomena.

How autoimmune diseases, which attack your own tissues and cells, work in the body

These diseases remain some of medicine's thorniest problems because the immune system can mistakenly attack almost any tissue in the body, resulting in myriad diseases, including lupus (numerous tissues affected), Hashimoto's (thyroid), and MS (the nervous system).

Anxiety is one of the world's most common mental health disorders, causing persistent excessive fear and worry that interferes with daily activities.

Aging is a complex biological process affecting our cells, tissues, and organs.

How did archaeology come to be?

Archaeology, also spelled archeology, is the scientific study of the material remains of past human life and activities. So when did it become an official body of science? Britannica answers this question and more in this article on the history of...

There's no definitive test for inflammation, or a baseline for what's considered normal

Existing tests can pick up proteins that indicate an immune response—in particular C-reactive protein, which the liver produces when the body's stressed—but that won't tell you why there's inflammation nor if it's chronic or acute inflammation. (Some users may experience a paywall.)

Why are women more likely to suffer autoimmune diseases than men?

A majority of Americans with autoimmune diseases have more than one X chromosome, a typical marker of the female biological sex, according to a study published in February of 2024. During fetal development, cells side with one X chromosome over the other, preventing the overproduction of X-chromosome-specific proteins and shutting down the twin chromosome. This article explores how this X-chromosome inactivation can lead to autoimmune disorders by generating antibodies to the body's own tissues.

Autoimmune disorders are one of the top 10 killers of young and middle-aged women

Studies in the US and the UK, though conducted decades ago, have underscored that autoimmune diseases, when grouped together, are a top killer of women.

"Plaques" and "tangles" are top potential causes of Alzheimer's—but questions remain

The exact causes of Alzheimer's—and how to treat it—continue to be the subject of intense research. Two leading factors are amyloid beta plaques and tau protein tangles, which effectively pile up in the brain and interfere with neurons and cause cell death, which manifests as memory loss and other symptoms.

Scleroderma, which causes skin to harden and scar, has no FDA-approved treatment

It's an autoimmune disease that disproportionately causes worse complications in African American people for unknown reasons. It causes the body to overproduce collagen after the immune system attacks the body's own connective tissue, leading to excess collagen deposits and restricted blood circulation as small blood vessels are damaged. It can damage various organs, including the lungs.

Inflammaging appears to differ across global populations

Chronic, low-grade inflammation linked to aging is a byproduct of our industrialized lifestyles, according to recent research. The work compared two industrialized populations with two Indigenous, non-industrialized populations in Bolivia and Malaysia, and found that inflammation levels in the Indigenous groups—unlike the industrialized ones—did not seem to differ by age.

The subjectivity of pain means that one person's kidney stones may be another's childbirth, but most sources of pain do have objective, underlying causes.

There are multiple types of multiple sclerosis—they differ by attack patterns

When your immune system targets the nervous system, this can cause new or worsening symptoms and the development of scarring or damage within the central nervous system. Relapsing-remitting MS is the most common type of the disease—it includes progressive bouts of attacks that occur months or years apart.

America's top causes of death are heart disease, cancer, accidents, and stroke

Heart disease killed more than 680,000 people in 2023 and cancer killed around 613,000 people that year. Both causes of death are far above the next leading cause of death—accidents, which numbered around 223,000. Provisional data for 2024 indicates the leading causes of death remained the same.

What is cardiovascular disease?

Cardiovascular diseases are a range of related health conditions that develop in the heart and blood vessels. This article and related infographics detail cardiovascular disease types and treatments.

Chronic inflammation can cause cellular damage and could lead to cancer

Over time, this cellular defense system can inadvertently damage cells and tissues when it's in this heightened alarm mode over a prolonged period. This occurs because, when immune cells are sent somewhere without a true target, they may attack healthy cells and tissues.

Doctors explain that most ear infections—but not swimmer's ear—affect the middle ear

A typical ear infection occurs in the area behind the eardrum, but swimmer's ear is an infection of the ear canal. Its characteristic symptom is pain whenever the ear is moved, though it can also include itching and a sense of fullness. Symptoms typically begin within a few days or a week of a water buildup not being addressed.

Yoga can be beneficial for aging practitioners

Studies suggest that yoga can help alleviate several diseases associated with aging by lowering blood pressure, reducing blood fat levels, and combating obesity. It has also been shown to increase telomerase activity, which helps slow cell aging.