Osteoarthritis

What happens in osteoarthritis

Healthy joints are lined with smooth cartilage and lubricated by fluid from the joint lining. In osteoarthritis the balance between cartilage damage and repair is lost. The cartilage thins and roughens, the bone underneath thickens and grows bony spurs (osteophytes), the joint lining becomes mildly inflamed, and the surrounding ligaments and muscles weaken. The joint space narrows and the joint can change shape.

Doctors now see OA as a disease of the whole joint, not just cartilage. That is why strengthening muscles and reducing load help even though cartilage does not regrow.

Symptoms of osteoarthritis

Early signs

• Joint pain during or after activity that eases with rest
• Stiffness after getting up or after sitting, usually lasting less than 30 minutes
• Aching after a long walk, stairs or gardening
• A grating, crackling or crunching feeling (crepitus)

Later symptoms

• Pain with less activity, and sometimes at rest or at night
• Reduced range of movement: trouble bending the knee, putting on socks or gripping
• Bony swelling of finger joints or the knee
• Episodes of mild swelling (a "flare"), often after overuse
• Joint giving way or locking
• Visible changes in shape, such as bowed knees or bent fingers

Symptoms often fluctuate over weeks and months. X-ray damage and pain do not always match: some people with marked X-ray changes have little pain, and vice versa.

Osteoarthritis by joint

Causes and risk factors

• Age: risk rises steadily after 40 to 50.
• Sex: women are more often affected, particularly after menopause and in the hands and knees.
• Excess weight: each extra pound adds several pounds of force across the knee when walking, and fat tissue releases inflammatory substances that affect even non-weight-bearing joints such as the hands.
• Joint injury: a torn meniscus or ACL, a fracture into the joint, or a dislocation can lead to OA years later.
• Repetitive stress: jobs with heavy lifting, kneeling or squatting.
• Genetics: hand and hip OA in particular run in families.
• Joint shape and alignment: hip dysplasia, bow legs or knock knees.
• Muscle weakness, especially of the thigh muscles.
• Other joint diseases: previous gout, rheumatoid arthritis or joint infection.

Osteoarthritis vs rheumatoid arthritis

How osteoarthritis is diagnosed

NICE guidance says OA can be diagnosed without tests in people aged 45 or older with activity-related joint pain and morning stiffness of 30 minutes or less. Your doctor will:

• ask about pain, stiffness, function and past injuries
• examine the joint for swelling, bony enlargement, crepitus, range of movement and alignment
• consider X-rays if the picture is unusual or surgery is being considered; they show joint space narrowing and bone spurs
• order blood tests or joint fluid analysis only to rule out other conditions such as rheumatoid arthritis, gout or infection

MRI is rarely needed for OA itself.

Osteoarthritis treatment

Guidelines from the American College of Rheumatology and NICE agree that the core treatments are exercise, weight management and education, with medicines added for symptom control.

Exercise: the most effective treatment

• Strengthening exercises for the muscles around the joint, such as the thigh and hip muscles for knee and hip OA
• Low-impact aerobic activity: walking, cycling, swimming or water aerobics, aiming for 150 minutes a week
• Range-of-motion and balance exercises, including tai chi for knee OA
• Physical therapy to set up a program and correct technique

Some soreness during exercise is acceptable if it settles within about 24 hours. Exercise does not wear joints out faster; it reduces pain and improves function as much as many medicines.

Weight loss

For people with knee or hip OA who are overweight, losing 5% to 10% of body weight meaningfully reduces pain and improves function. Greater losses bring greater benefit.

Pain relief

• Topical NSAIDs (such as diclofenac gel) are first choice for knee and hand OA. They have far fewer side effects than tablets. Follow the label directions.
• Oral NSAIDs (ibuprofen, naproxen) at the lowest effective dose for the shortest time. They can cause stomach bleeding and kidney problems and raise blood pressure and heart risk, so check with your doctor if you are older or have these conditions.
• Acetaminophen (paracetamol) has only a small benefit for OA but may help some people for short periods. Do not exceed the label dose.
• Duloxetine can help people with widespread or persistent pain.
• Opioids, including tramadol, are generally not recommended: benefits are small and risks are significant.

Injections

• Corticosteroid injections give short-term relief, usually for weeks, during flares. They are limited to a few per year per joint.
• Hyaluronic acid (gel) injections are not recommended by most current guidelines because the benefit is small.
• Platelet-rich plasma and stem cell injections are not recommended outside research.

Devices and daily aids

• Cane in the hand opposite the painful hip or knee
• Knee braces, thumb splints and supportive footwear
• Jar openers, raised toilet seats and other assistive devices

Surgery

• Joint replacement of the hip or knee is very effective for severe OA when pain and disability persist despite other treatments. Most people get major pain relief, and modern implants commonly last 20 years or more.
• Osteotomy (realigning the bone) for some younger people with knee OA on one side.
• Thumb base surgery for severe thumb OA.
• Knee arthroscopy (a "clean-out") is not recommended for OA, because trials show no lasting benefit.

Supplements and other options

Glucosamine and chondroitin have not shown consistent benefit in high-quality trials and are not recommended by the ACR. Heat or cold packs, massage and acupuncture help some people. Turmeric (curcumin) has limited evidence.

Complications

• Reduced mobility, falls and loss of independence
• Poor sleep and low mood
• Weight gain from inactivity, which worsens joint pain
• Side effects from long-term NSAID use

Living with osteoarthritis

OA is long-term, but it does not always get worse, and many people's symptoms stay stable for years. Pace activities through the day, keep moving even on bad days with gentler exercise, and plan ahead for flares with heat, rest and topical treatments. The Arthritis Foundation and CDC-recommended programs such as Walk With Ease offer structured support.

Preventing osteoarthritis

• Keep to a healthy weight.
• Stay active and keep the thigh and hip muscles strong.
• Protect joints from injury: warm up, use good technique in sport, and do knee injury prevention programs for sports such as soccer and basketball.
• Get joint injuries properly treated and rehabilitated.

Frequently asked questions

What are the first signs of osteoarthritis?

Early signs are joint pain during or after activity, brief stiffness when you get up in the morning or after sitting, and a crunching or grating feeling in the joint. Symptoms usually start gradually in one or a few joints, often the knees, hips, hands or base of the thumb.

What causes osteoarthritis?

Osteoarthritis results from an imbalance between joint damage and repair. Key risk factors are older age, excess weight, past joint injuries, repetitive heavy joint use, genetics, joint misalignment and weak muscles. It is not caused only by aging or overuse; low-grade inflammation also plays a part.

Can osteoarthritis be reversed?

Lost cartilage does not grow back, so the joint changes cannot be reversed. However, symptoms can improve a great deal. Exercise, weight loss and pain relief reduce pain and improve function for most people, and many stay stable for years. Joint replacement can largely eliminate pain in severe cases.

Is walking good for osteoarthritis?

Yes. Walking is one of the best exercises for knee and hip osteoarthritis. It strengthens muscles, helps weight control and reduces pain over time. Start with shorter walks, wear supportive shoes, use a cane if needed and increase gradually. Mild soreness that settles within a day is normal.

What is the difference between osteoarthritis and rheumatoid arthritis?

Osteoarthritis is joint damage and remodeling, usually in older adults, causing activity-related pain and brief stiffness. Rheumatoid arthritis is an autoimmune disease that inflames the joint lining, often symmetrically in the hands and feet, with long morning stiffness, fatigue and positive blood tests. Treatments are very different.

When should I consider joint replacement?

Consider it when severe hip or knee pain and stiffness keep limiting your daily life and sleep despite months of exercise, weight management and medicines, and X-rays confirm advanced damage. Age alone is not a barrier. An orthopedic surgeon will discuss benefits, risks and recovery.