The hip is one of the largest joints in the body, with a ball-and-socket design— the femoral head (ball) sits in the acetabulum (socket)—connecting thigh to pelvis. The surface of the bones is covered in cartilage, which acts as a cushion and allows movement. In a healthy hip, a small amount of fluid is produced by a layer of tissue membrane surrounding the joint, lubricating the cartilage and eliminating friction.
Understanding Hip Joint Degeneration
Arthritis, or inflammation of the joints, affects at least 50 million Americans and approximately 25 percent of seniors. Over time, arthritis can cause deterioration in the joints. When weight-bearing joints are affected, such as the knee or hip, this pain is the leading cause of disability and joint replacement surgery in the United States.
Osteoarthritis, a degenerative joint disease, is the most common form of arthritis. Osteoarthritis affects the cartilage surrounding the joint. Pain may be steady or intermittent, accompanied by swelling or stiffness at particular times of the day, and some people can even hear or feel the crunching of bones rubbing together.
Rheumatoid arthritis is a chronic autoimmune disease, where the body’s immune system attacks and can even destroy healthy joints. The inflamed area is usually the tissue lining the joint, causing irritation and damage to the cartilage, pain, swelling and stiffness as well as decreased range of motion. The ability to perform normal everyday activities may be impaired.
When the cartilage is broken down by arthritis, the bones rub together causing joints to become swollen or stiff and function to become limited and painful. This inflammation is prompted by the development of bone spurs, or bone overgrowth, and an increased production of fluid in the joint, which further impairs function.
Hip Replacement Surgery
Hip replacement surgery can offer restored mobility and eliminate joint pain, and is recommended for those who have hip pain that is limiting to daily life and unresponsive to conservative treatments.
In hip replacement surgery, the damaged hip joint is removed and replaced with a prosthetic implant. A metal stem with a metal or ceramic ball placed on the top is fitted into the center of the thighbone, replacing the femoral head. The damaged cartilage of the acetabulum is removed and replaced with a socket that is secured with screws or cement. A plastic, ceramic or metal insert is placed between the prosthetic ball and socket to allow for smooth range of motion.
Particular attention must be paid to the type of hip implant being used. The flawed design of several metal-on-metal hip implants, including the DePuy ASR and Stryker Rejuvenate and ABGII, has led to serious complications. Implanted in thousands of Americans before being recalled, these hip implants can cause patients to develop toxic levels of metal in the tissues and blood stream, can cause tissue loss and bone death and are likely to fail early, necessitating revision surgery.
Patients should speak with their doctor about using an implant that contains components made from a variety of materials.
Linda Grayling writes for Drugwatch.com. Linda has a number of professional interests, including keeping up with the latest developments in the medical field.