A Healthy Hip
The hip joint is a ball-and-socket joint made up of the head of the femur (thigh bone) and the socket of the pelvis (acetabulum). Cartilage covers these surfaces and acts as a cushion, allowing the ball to move easily in the socket as you walk and move your leg forward, backward and sideways in all planes of motion.
The Arthritic Hip
Arthritis is any degenerative condition of the joint cartilage resulting in pain and inflammation, causing reduced motion and difficulty with walking. In an arthritic hip, the cartilage cushion wears out and the surfaces of the bones become rough and irregular. Common causes of hip arthritis are the following:
Osteoarthritis or degenerative joint disease affects the cartilage lining on the ends of bones. The cartilage becomes roughened and thinned and no longer allows smooth movement of the joint. Eventually, the bones may touch as the hip moves, causing a grinding sensation. When this happens, pain, stiffness, swelling, and disability are frequent consequences. Total joint replacement surgery is frequently used to treat severe osteoarthritis.
Rheumatoid arthritis is a disease of the tissue (synovium) which lines the inside of joints. In rheumatoid arthritis, the synovial lining is abnormal. It becomes thick and releases materials that damage or destroy cartilage. The result is a joint which is inflamed (hot, swollen, and painful), stiff and deformed. The cause of rheumatoid arthritis is not known, but it may be a reaction against the body’s own tissues (autoimmune disease).
Trauma caused by a fall or accident may cause premature cartilage breakdown, resulting in a total hip replacement. Avascular necrosis, or osteonecrosis, is the death of bone tissue due to a lack of blood supply. The death of bone tissue can lead to tiny breaks in the bone and the bone’s eventual collapse, requiring a total hip replacement.