Overview
Osteoarthritis is a degenerative joint condition where cartilage that cushions the ends of bones gradually wears down. As cartilage thins, the joint becomes less able to glide smoothly, leading to pain, stiffness, and reduced function. It most commonly affects knees, hips, hands, and the spine.

Causes and risk factors
Osteoarthritis develops over time due to joint loading and cartilage breakdown. Risk rises with age, prior joint injury, repetitive stress, obesity, certain occupations or sports, and family history. Malalignment or muscle weakness can increase joint stress and accelerate wear.

Symptoms
Typical symptoms include joint pain with activity, stiffness after rest (often brief in the morning), swelling, reduced range of motion, crepitus (grinding or clicking), and sometimes joint deformity. Symptoms may fluctuate and usually progress gradually.

Diagnosis
Diagnosis is based on history, physical examination, and imaging. X-rays can show joint space narrowing, osteophytes (bone spurs), and changes in bone. MRI is not routinely needed but can show cartilage or soft‑tissue damage when diagnosis is uncertain.

Treatment
First‑line care focuses on pain relief and function: activity modification, weight management, targeted exercise, and physical therapy. Medicines include topical or oral NSAIDs and acetaminophen when appropriate. In some cases, injections (corticosteroid or viscosupplementation) may be used. Surgery (e.g., joint replacement) is considered when pain and disability are severe despite conservative treatment.

Self‑care and prevention
Maintain a healthy body weight, keep muscles strong around the joint, and avoid high‑impact activities if they worsen symptoms. Use supportive footwear and consider braces or assistive devices when needed.

When to seek care
See a clinician if joint pain limits daily activities, swelling persists, or the joint becomes unstable or deformed.