There are four primary diseases of the hip that may indicate the need for a total or partial hip replacement:
Osteoarthritis of the hip is a disease which wears away the cartilage between the femoral head and the acetabulum, eventually causing the two bones to scrape against each other, raw bone on raw bone. When this happens, the joint becomes pitted, eroded and uneven. The result is pain, stiffness and instability, and in some cases, motion of the leg may be greatly restricted.
Patients with osteoarthritis often develop large bone spurs, or osteophytes, around the joint, further limiting motion.
Osteoarthritis is a common, degenerative disease, and although it most often occurs in patients over the age of 50, it can occur at any age, especially if the joint is in some way damaged.
Causes - Osteoarthritis of the hip is a condition commonly referred to as "wear and tear" arthritis. Although the degenerative process may accelerate in persons with a previous hip injury, many cases of osteoarthritis occur when the hip simply wears out. Some experts believe there may exist a genetic predisposition in people who develop osteoarthritis of the hip. Abnormalities of the hip due to previous fractures or childhood disorders may also lead to a degenerative hip. Osteoarthritis of the hip is the most common cause for both total hip replacement and hip resurfacing.
Symptoms - The first and most common symptom of osteoarthritis is pain in the hip or groin area during weight bearing activities such as walking. People with hip pain usually compensate by limping, or reducing the force on the arthritic hip. As a result of the cartilage degeneration, the hip loses its flexibility and strength, and may lead to the formation of bone spurs. Finally, as the condition worsens, the pain may be present all the time, even during non weight-bearing activities.
Unlike osteoarthritis, which is a "wear and tear" phenomenon, rheumatoid arthritis is a chronic inflammatory disease that results in joint pain, stiffness and swelling. The disease process leads to severe, and at times rapid, deterioration of multiple joints, resulting in severe pain and loss of function.
Causes - Although the exact cause of rheumatoid arthritis is unknown, some experts believe that a virus or bacteria may trigger the disease in people having a genetic predisposition to rheumatoid arthritis. Many doctors think rheumatoid arthritis is an autoimmune disease in which the synovial tissue of the joint is attacked by one's own immune system. The onset of rheumatoid arthritis occurs most frequently in middle age and is more common among women.
Symptoms - The primary symptoms of rheumatoid arthritis are similar to osteoarthritis and include pain, swelling and the loss of motion. In addition, other symptoms may include loss of appetite, fever, energy loss, anemia, and rheumatoid nodules (lumps of tissue under the skin). People suffering with rheumatoid arthritis commonly have periods of exacerbation or "flare ups" where multiple joints may be painful and stiff.
Developmental Dysplasia of the Hip
Developmental dysplasia of the hip (DDH), also called hip dysplasia, is a lifelong condition, shared by one in 1,000 people. Because DDH patients are born with an altered hip anatomy, the joint doesn't develop the normal wear patterns over the years. This leads to "wear and tear" arthritis at a relatively early age.
Causes - The most significant risk factor for DDH is a family history of the disorder. Women have a higher rate of DDH, as do first-born children and babies delivered breech.
Symptoms - Developmental dysplasia of the hip often can be diagnosed in the first year of life. Symptoms include diminished leg movement in the affected hip, shortening of the leg on the affected side, or asymmetry in leg positions. One or both hips may have DDH.
Avascular necrosis (AVN) of the hip results when poor blood circulation starves the bones that form the hip joint. In time, the starved bone dies, and the hip joint collapses. AVN, sometimes called hip osteonecrosis, is most prevalent in younger or middle-aged adults.
Causes - Alcoholism and corticosteroids are by far the leading causes of AVN. In rarer cases, AVN can result from a blockage in blood vessels from sickle cell anemia or fat particles, or from dislocation of the hip due to trauma.
Symptoms - Hip pain, especially after standing or walking, is the most common symptom. Hip AVN most commonly afflicts the femoral head, where the femur (or thighbone) attaches to the pelvis (or hip bone). The femoral head may weaken and collapse.