Joint pain is one of the most common reasons people visit a doctor, and arthritis is behind much of it. But arthritis is not one disease. It is an umbrella term for more than 100 conditions that affect joints and the tissues around them, each with different causes and treatments. This guide walks through how joints work, the most common types of arthritis, other causes of joint pain, warning signs that need urgent care, and the treatment options you can discuss with your clinician.
What is a joint?
A joint is a place where two or more bones meet. Of the 206 bones in the adult skeleton, most connect at joints that let you bend, twist, grip and walk. The most mobile ones, such as the knee, hip, shoulder and finger joints, are called synovial joints. In these, the ends of the bones are capped with smooth, slippery cartilage that lets them glide. The joint is wrapped in a capsule lined by a thin membrane called the synovium, which produces fluid that lubricates and nourishes the cartilage. Ligaments hold the bones together, tendons connect muscles to bone, and small fluid-filled sacs called bursae cushion areas where tissues rub.
Problems with any of these parts can cause pain. Arthritis generally refers to disease of the joint itself, while conditions such as bursitis and tendinitis affect the structures around it. You can explore how joints fit together in our interactive bone explorer.
How common is arthritis?
Arthritis is very common. A CDC analysis of national survey data for 2019 to 2021 found that about 53.2 million US adults, or 21.2%, had been told by a health professional that they have arthritis. It becomes more common with age: nearly half of adults 65 and older reported a diagnosis. Women were more likely than men to be affected.
Globally, the World Health Organization estimates that about 528 million people were living with osteoarthritis in 2019, an increase of 113% since 1990. About 73% of them were older than 55, and around 60% were women. The knee is the most frequently affected joint, followed by the hip and hand.
Osteoarthritis vs rheumatoid arthritis
These are two of the best-known forms of arthritis, and they are often confused. They have very different causes.
Osteoarthritis (OA) is the most common type. The cartilage in a joint gradually thins and roughens, and the joint responds by remodeling: bony growths called osteophytes can form at the edges, the lining may thicken, and supporting tissues may loosen. It was once described as simple wear and tear, but experts now see it as an active process influenced by age, injury, weight, genetics and joint shape. Many people have changes on X-rays without symptoms, and pain does not always match how the joint looks on imaging.
Rheumatoid arthritis (RA) is an autoimmune disease. The immune system mistakenly attacks the synovium, causing inflammation that, without treatment, can damage cartilage and bone. According to NIAMS, women are two to three times more likely than men to develop RA. Because it is a whole-body disease, it can also cause fatigue, low-grade fever and loss of appetite.
| Feature | Osteoarthritis | Rheumatoid arthritis |
|---|---|---|
| Basic cause | Breakdown and remodeling of cartilage and bone | Autoimmune inflammation of the joint lining |
| Typical onset | Gradual; becomes more common with age | Can begin at any adult age; may develop over weeks to months |
| Joints commonly affected | Knees, hips, hands (fingertips, thumb base), neck, lower back | Wrists, hands and feet, often the same joints on both sides |
| Morning stiffness | Usually less than 30 minutes | Often more than 30 minutes |
| Pain pattern | Worse with use, eases with rest; may disturb sleep later on | Present at rest and with movement; joints warm and swollen |
| Whole-body symptoms | Generally none | Fatigue, occasional low-grade fever, reduced appetite |
| Blood tests | No specific test; used to rule out other causes | Rheumatoid factor, anti-CCP antibodies and inflammation markers often abnormal |
| Main treatment approach | Exercise, weight management, pain relief, joint replacement if severe | Early disease-modifying medicines to control inflammation, plus exercise and self-care |
Other types of arthritis
Gout
Gout happens when urate (uric acid) builds up and forms needle-shaped crystals in and around a joint, triggering intense inflammation. It often begins suddenly, frequently at night, with a red, hot, swollen and extremely painful joint, classically the big toe. Flares usually settle within a week or two, but repeated attacks without treatment can lead to hard lumps called tophi and joint damage. Risk factors include family history, male sex, older age, obesity, chronic kidney disease, alcohol and sugar-sweetened drinks. With proper treatment and lifestyle changes, gout can be well controlled.
Psoriatic arthritis
Psoriatic arthritis is an inflammatory arthritis linked to the skin condition psoriasis. Most people have had psoriasis for years before joint symptoms appear, though joints can come first. It can cause stiff, swollen joints, pain where tendons attach to bone (such as the back of the heel), a whole finger or toe that swells up, and nail pitting or separation. Early treatment is associated with less joint damage.
Ankylosing spondylitis
Ankylosing spondylitis is an inflammatory arthritis that mainly affects the spine and the joints where the spine meets the pelvis. Its hallmark is low back or hip pain and stiffness that is worse after rest, such as overnight, and improves with movement. Symptoms usually start before age 45. In severe cases, vertebrae can fuse. Physical therapy, regular exercise and medication help manage it.
Other causes of joint pain
Not all joint pain is arthritis. Common alternatives include:
- Bursitis: inflammation of a bursa, often in the shoulder, hip, elbow or knee, typically from pressure, kneeling or repeated movement. It usually settles with rest and self-care within a few weeks.
- Tendinitis: irritation of a tendon from overuse or strain, such as tennis elbow or Achilles tendinitis.
- Injuries: sprains, ligament or cartilage tears (such as a torn meniscus in the knee), dislocations and fractures. See our broken bone healing guide for more on fractures.
- Infection: septic arthritis, a bacterial infection inside a joint, is a medical emergency.
- Other conditions: lupus, viral illnesses, fibromyalgia and referred pain from the spine can all cause joint symptoms.
Common symptoms
Symptoms vary by type, but people with arthritis often notice:
- Pain in or around one or more joints
- Stiffness, especially in the morning or after sitting
- Swelling, which may be soft (fluid or thickened lining) or hard and knobbly (bony growth)
- Reduced range of motion or difficulty with tasks such as stairs, rising from a chair or gripping
- Grating or crackling sensations, or a feeling that a joint gives way
- Warmth and redness over the joint in inflammatory types
- Fatigue, poor sleep and low mood, which are common with chronic pain
Clues that point toward inflammatory arthritis include prolonged morning stiffness, swelling in several joints, a symmetrical pattern, and symptoms such as fatigue or low-grade fever.
Red flags: when to seek urgent care
- A joint that suddenly becomes very painful, hot, swollen or red, especially with fever, chills or feeling generally unwell, which may signal infection
- Being unable to move a joint or put weight on it
- Joint pain after an injury with obvious deformity, a popping sound followed by rapid swelling, or inability to bear weight
- Numbness, tingling, coldness or color change below an injured joint
- Back pain with new loss of bladder or bowel control, numbness in the groin area, or leg weakness
- Joint pain with a spreading rash, eye pain or redness, or chest pain
Septic arthritis can destroy a joint quickly, so do not wait to see whether it settles.
How arthritis is diagnosed
There is rarely a single test for arthritis. Diagnosis usually combines several steps:
- History and examination: your clinician will ask which joints hurt, how long stiffness lasts, what makes it better or worse, and about family history, skin conditions and other symptoms. They will examine joints for swelling, warmth, tenderness and movement.
- Imaging: X-rays show joint space narrowing, bone spurs and erosions. Ultrasound and MRI can reveal inflammation, fluid and soft-tissue damage. For osteoarthritis, diagnosis is often made clinically, and imaging may add little in straightforward cases.
- Blood tests: inflammation markers (ESR and CRP), rheumatoid factor and anti-CCP antibodies for RA, uric acid for gout, and other tests to rule out conditions such as lupus or infection.
- Joint fluid analysis: drawing fluid from a swollen joint with a needle can identify crystals in gout or bacteria in infection.
Treatment options
Treatment depends on the type of arthritis, how severe it is and your personal goals. Most plans combine several approaches.
Exercise and physical therapy
Exercise is a core treatment for almost every kind of arthritis. Strengthening the muscles around a joint takes pressure off it, while range-of-motion and aerobic activity reduce stiffness and improve function. A physical therapist can design a safe program and suggest braces, insoles or walking aids. Our guide to exercises for strong bones and the bone exercise planner offer starting points.
Weight management
Extra body weight increases the load on knees and hips, and losing weight when needed can ease pain and improve movement in weight-bearing joints. It also lowers the risk of gout flares.
Pain relief and local treatments
Over-the-counter pain relievers, anti-inflammatory gels and tablets, and heat or cold packs can help manage symptoms. Anti-inflammatory medicines carry risks for the stomach, kidneys and heart with long-term use, so ask your clinician or pharmacist which options are safe for you. The WHO does not recommend opioid painkillers for osteoarthritis.
Injections
Corticosteroid injections into a joint can calm a flare and provide temporary relief. Your doctor will weigh the benefits against limits on how often they can be repeated.
Disease-modifying medicines for inflammatory arthritis
For rheumatoid, psoriatic and related types of arthritis, the goal is to control the immune response early, before permanent damage occurs. Disease-modifying antirheumatic drugs (DMARDs) are usually the first step, and biologic or targeted medicines may be added if needed. These treatments require regular monitoring by a specialist. Gout is treated with medicines that settle flares and, for frequent attacks, medicines that lower urate over the long term.
Joint replacement and other surgery
When pain and disability remain severe despite other treatments, surgery may be an option. According to the American Academy of Orthopaedic Surgeons, knee replacement is considered for people with severe pain or stiffness that limits daily activities, pain at rest, or deformity, who have not improved with medicines, injections or therapy. The procedure resurfaces the damaged joint with metal and plastic components. Hip and shoulder replacements follow similar principles.
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Living well with arthritis
- Keep moving. Gentle daily activity usually helps more than rest. Walking, cycling, swimming and water exercise are joint-friendly options.
- Pace yourself. Break big jobs into smaller chunks and alternate demanding tasks with lighter ones.
- Use heat and cold. Warmth can ease stiffness; a wrapped ice pack can calm swelling.
- Protect your joints. Supportive shoes, jar openers, raised seats and other aids reduce strain.
- Look after sleep and mood. Chronic pain and poor sleep feed each other; let your care team know if either is a problem.
- Stay on top of treatment. For inflammatory arthritis, taking medicines as prescribed and keeping monitoring appointments helps prevent damage.
Rheumatologist or orthopedic surgeon?
Most people start with their primary care doctor, who can assess symptoms, order tests and refer you on. A rheumatologist specializes in the medical diagnosis and treatment of arthritis and autoimmune conditions. See one if you have suspected rheumatoid, psoriatic or other inflammatory arthritis, recurrent gout, swelling in several joints, or unexplained joint pain with whole-body symptoms. An orthopedic surgeon focuses on the structure of bones and joints. Referral makes sense for injuries such as ligament or cartilage tears, or for advanced osteoarthritis when non-surgical treatments are no longer enough and joint replacement may be considered. Physical therapists, podiatrists and occupational therapists are valuable members of the team for nearly every type.
Ready to take the next step? Use our find care tool to connect with a bone and joint specialist near you, or browse more topics on our conditions page.