It differs from osteoarthritis because it initially involves the synovial membrane and not the cartilage, and it strikes less frequently and at a younger age than osteoarthritis. It targets the synovial membrane, causing chronic inflammation. It may have a genetic component or be triggered by environmental factors.

Symptoms include persistent pain, stiffness, joint swelling, and functional limitation, often bilateral. Pain is more pronounced in the morning or after inactivity.

Diagnosis is based on clinical examination, lab tests (rheumatoid factor, anti-CCP antibodies), and imaging studies (ultrasound, X-rays, MRI). Treatment includes anti-inflammatory drugs, immunosuppressants, and biological therapies. In advanced stages, hip replacement surgery may be necessary.

If uncontrolled, it can cause severe joint damage, deformities, loss of function, and reduced quality of life.