Arthritis

What arthritis is

A joint is where two bones meet. The bone ends are covered with smooth cartilage, and the joint is enclosed in a capsule lined by the synovium, which makes lubricating fluid. Arthritis happens when the cartilage breaks down, the synovium becomes inflamed, or crystals or infection invade the joint.

Arthritis falls into broad groups:

• Degenerative (mechanical): osteoarthritis, where cartilage gradually wears thin.
• Inflammatory: the immune system attacks the joint lining, as in rheumatoid arthritis, psoriatic arthritis and ankylosing spondylitis.
• Crystal: uric acid (gout) or calcium crystals (pseudogout) trigger sudden inflammation.
• Infectious: bacteria, viruses or fungi infect the joint (septic arthritis).

If your main concern is a swollen, hot joint right now and what might be causing it, see joint inflammation.

Types of arthritis

Symptoms of arthritis

• Pain: aching, sometimes sharp, in or around the joint
• Stiffness: especially in the morning or after sitting
• Swelling: soft swelling from fluid in inflammatory arthritis, bony swelling in osteoarthritis
• Reduced movement: trouble bending, gripping or climbing stairs
• Warmth and redness: in inflammatory and crystal arthritis
• Grating or creaking (crepitus) in osteoarthritis
• Deformity: knobby finger joints (Heberden's and Bouchard's nodes), drifting fingers, bow legs
• Whole-body symptoms in inflammatory types: tiredness, low-grade fever, weight loss

Early signs of arthritis

• stiffness on waking that takes time to loosen
• joint pain after activity that used to be easy
• swelling in a knuckle, wrist or knee that comes and goes
• reduced grip strength, such as difficulty opening jars

Arthritis in the hands

Osteoarthritis affects the joints nearest the fingertips, the middle joints and the base of the thumb, causing bony bumps and pain when pinching. Rheumatoid arthritis typically affects the knuckles and middle joints on both hands with soft, warm swelling and long morning stiffness. Psoriatic arthritis may swell a whole finger. Telling them apart matters, because inflammatory types need early disease-modifying treatment.

Causes and risk factors

• Age: cartilage becomes less resilient over time.
• Sex: women are more likely to have osteoarthritis and rheumatoid arthritis; men more likely to have gout.
• Genes: family history of RA, psoriasis, ankylosing spondylitis or gout. HLA-B27 is linked to spondyloarthritis.
• Joint injury: a torn meniscus or ACL raises knee osteoarthritis risk years later.
• Excess weight: increases load on knees and hips and raises inflammation. Each 1 lb (0.45 kg) of weight adds about 4 lb (1.8 kg) of force across the knee when walking.
• Smoking: the strongest lifestyle risk factor for rheumatoid arthritis.
• Diet and medicines: alcohol, sugary drinks, red meat and diuretics raise gout risk.
• Infections: can trigger reactive or septic arthritis.

How arthritis is diagnosed

1. History and examination: which joints, pattern, duration of stiffness, skin, nails and eyes.
2. Blood tests: inflammatory markers (CRP, ESR), rheumatoid factor, anti-CCP antibodies, ANA, uric acid, and HLA-B27 where relevant. Blood tests are normal in osteoarthritis.
3. Joint fluid analysis: for crystals and infection in a swollen joint.
4. Imaging: X-rays show narrowed joint space and bone spurs in osteoarthritis and erosions in RA. Ultrasound and MRI detect early inflammation.

Inflammatory arthritis is best managed by a rheumatologist. Early referral, ideally within weeks of symptoms, improves long-term outcomes.

Treatment

For all types

• Exercise: the most effective long-term treatment for osteoarthritis and important for every type. Strength training, walking, cycling, swimming and tai chi reduce pain and improve function. Aim for 150 minutes of moderate activity a week, built up gradually.
• Weight loss: losing 5% to 10% of body weight significantly reduces knee pain.
• Physical and occupational therapy: exercises, braces, splints and tools for daily tasks.
• Heat and cold: heat for stiffness, cold for flares.

Medicines

• Topical NSAID gels (such as diclofenac) are a first choice for knee and hand osteoarthritis, with fewer side effects than tablets.
• Oral NSAIDs (ibuprofen, naproxen) at the lowest effective dose. They can cause stomach bleeding, kidney problems and raise blood pressure.
• Acetaminophen (paracetamol): modest benefit at best for osteoarthritis but useful for some.
• Steroid injections into a joint relieve a flare for weeks to months.
• Disease-modifying antirheumatic drugs (DMARDs): methotrexate, sulfasalazine, hydroxychloroquine and leflunomide slow or stop joint damage in inflammatory arthritis. They need regular blood monitoring.
• Biologic and targeted drugs: TNF inhibitors, IL-6, IL-17 and IL-23 inhibitors, and JAK inhibitors for disease not controlled by standard DMARDs.
• Gout: colchicine, NSAIDs or steroids for attacks; allopurinol or febuxostat to lower uric acid long term.

Opioids are generally not recommended for long-term arthritis pain.

Surgery

Joint replacement of the hip or knee is highly effective when pain and disability remain severe despite other treatments. Other options include joint fusion and, for some deformities, realignment surgery.

Complications and living with arthritis

• Reduced mobility and falls
• Joint deformity
• Higher risk of heart disease with rheumatoid arthritis and gout
• Depression, poor sleep and fatigue
• Osteoporosis from inflammation and steroid use
• Infections from immune-suppressing medicines

Practical tips: pace activities, use larger-handled tools, wear supportive shoes, keep up recommended vaccines when on DMARDs, and treat low mood, which makes pain worse.

Frequently asked questions

What are the first signs of arthritis?

Early signs include joint stiffness on waking, pain after activity, swelling that comes and goes, reduced range of motion and weaker grip. In inflammatory arthritis, morning stiffness lasting more than 30 minutes and swelling of small hand joints on both sides are typical.

What is the most common type of arthritis?

Osteoarthritis is the most common type. It affects tens of millions of Americans and usually involves the knees, hips, hands and spine. Rheumatoid arthritis is the most common autoimmune type, and gout is the most common inflammatory arthritis in men.

Can arthritis be cured?

Most types cannot be cured, but they can be controlled. Gout can be effectively prevented by lowering uric acid. Rheumatoid arthritis can go into remission with modern medicines. Osteoarthritis symptoms improve with exercise and weight loss, and joint replacement can eliminate pain in a badly damaged joint.

Is walking good for arthritis?

Yes. Regular walking strengthens muscles that support the joints, maintains movement and reduces pain over time in osteoarthritis and inflammatory arthritis. Start with short, flat walks, wear cushioned shoes and increase gradually. Some soreness is normal; sharp pain or swelling lasting more than 2 hours after exercise means you did too much.

What is the difference between arthritis and joint pain?

Joint pain is a symptom with many causes, including injuries, tendinitis and viral infections. Arthritis means a disease of the joint itself, either damage to cartilage or inflammation of the joint lining. Persistent joint pain with stiffness or swelling may be arthritis.

Does weather affect arthritis?

Many people with arthritis report more pain in cold, damp weather or when air pressure drops. Studies show mixed results, but the effect may be real for some people. Keeping warm, staying active indoors and planning activities on better days can help.