Inflammation

Arthritis literally means "inflammation of a joint." In some forms of arthritis, such as osteoarthritis, the inflammation arises because the smooth covering (articular cartilage) on the ends of bones wears away. In other forms of arthritis, such as rheumatoid arthritis, the joint lining becomes inflamed as part of a systemic disease. These diseases are considered the inflammatory arthritides.

The three most common types of inflammatory arthritis that affect the hip are:

    - Rheumatoid arthritis (RA): RA is a systemic disease of the immune system that usually affects multiple joints on both sides of the body at the same time.
    - Ankylosing spondylitis (AS): AS is a chronic inflammation of the spine and the sacroiliac joint (the point where the spine meets the pelvic bone) that can also cause inflammation in other joints.
    - Systemic lupus erythematosus (SLE or lupus): SLE is an autoimmune disease in which the body harms its own healthy cells and tissues.

Signs and symptoms
The classic sign of arthritis is joint pain. Inflammatory arthritis of the hip is characterized by a dull, aching pain in the groin, outer thigh, or buttocks. Pain is usually worse in the morning and lessens with activity; however, vigorous activity can result in increased pain and stiffness. The pain may limit your movements or make walking difficult.