Rheumatoid arthritis is a systemic autoimmune disease affecting the synovial membrane, causing chronic inflammation. The exact causes are unknown, but both genetic and environmental factors are believed to trigger an abnormal immune response.

Common symptoms include pain, swelling, stiffness (especially in the morning or after rest), warmth around the joint, and reduced mobility. The condition often affects both knees symmetrically and can progress over time.

Diagnosis involves clinical history, physical examination, blood tests (e.g., rheumatoid factor and anti-CCP antibodies), and imaging studies (ultrasound, MRI, X-rays). Treatment aims to control inflammation with disease-modifying antirheumatic drugs (DMARDs), biologic therapies, physical therapy, and surgery in advanced cases.

If not properly managed, it may lead to permanent joint damage, deformities, loss of function, and systemic complications. Early and continuous management is essential to prevent long-term consequences.