Traditional hip replacement has been performed - with a few modifications -- for more than 40 years. The incision is five to eight inches long, and patients generally require four to five days of hospitalization. They may stand or walk with the help of a cane, crutches or a walker the day after receiving their new hip joint.

Minimally invasive hip replacement surgery involves one or two smaller incisions. The artificial joint is the same as the type implanted during traditional surgery, but the instruments that the surgeon uses are different. The apparent advantages of this approach are that patients typically spend less time in surgery, lose less blood, experience less pain, require only one to two days of hospitalization, and recover sooner.

People who are candidates for minimally invasive hip replacement are generally young, healthy and highly motivated to recover quickly. However, the procedure may also benefit people with health problems severe enough to rule out traditional surgery. The decision on which procedure is appropriate for a specific patient should be based on a complete evaluation of that patient and a discussion of risks and benefits by the patient and the surgeon.

Studies suggest that minimally invasive hip replacement surgery is safe and effective and that it streamlines the recovery process. However, the long-term benefits have not yet been documented, and extensive study and development are continuing.

In the meantime, new technologies for imaging and computer-assisted implant placement are being developed, and surgeons are gaining more experience with minimally invasive surgery. New designs and materials for implants also are being developed, with hope of prolonging the lifespan of joint replacements.

Anatomy of a Hip
The hip is a ball and socket joint formed by part of the pelvis and the upper part of the femur, which is a large bone that extends from the knee to the hip. A smooth substance called cartilage covers the ends of the bones and allows for pain-free movement. When cartilage is damaged, the joint becomes stiff and painful. The pain may become so severe that the patient limits use of the joint, which weakens the muscles around it and makes movement even more difficult.

The goals of hip replacement surgery are to relieve the pain and improve the patient's mobility. A surgeon replaces the damaged ball at the upper end of the femur with a metal ball attached to a metal stem. A plastic socket is implanted in the pelvis to replace the damaged socket.

Hip Facts

• Osteoarthritis, the most common form of arthritis, is the major reason that people have total hip replacement surgery. Other reasons include injuries to the hip joint, rheumatoid arthritis, and bone tumors.

• Hip replacement surgery is one of the most important surgical advances of the 20th century. Improvements in surgical techniques and technology have greatly increased the effectiveness of this procedure since it was first performed in 1960.

• Patients who undergo hip replacement surgery are generally between the ages of 60 and 75.

• The total number of all hip joint procedures performed in 2000 was 295,000. They include conventional and minimally invasive surgery, partial hip replacement, and replacement of previously implanted joints. As the population ages, the number of total hip replacement surgeries will continue to increase.