What Is a Hip Replacement?

Hip replacement, or arthroplasty, is a surgical procedure in which the diseased parts of the hip joint are removed and replaced with new, artificial parts. These artificial parts are called the prosthesis. The goals of hip replacement surgery are to improve mobility by relieving pain and improve function of the hip joint.

Who Should Have Hip Replacement Surgery?

The most common reason that people have hip replacement surgery is the wearing down of the hip joint that results from osteoarthritis. Other conditions, such as rheumatoid arthritis (a chronic inflammatory disease that causes joint pain, stiffness, and swelling), a vascular necrosis (loss of bone caused by insufficient blood supply), injury, and bone tumors also may lead to breakdown of the hip joint and the need for hip replacement surgery.

Before suggesting hip replacement surgery, the doctor is likely to try walking aids such as a cane, or non-surgical therapies such as medication and physical therapy. These therapies are not always effective in relieving pain and improving the function of the hip joint. Hip replacement may be an option if persistent pain and disability interfere with daily activities. Before a doctor recommends hip replacement, joint damage should be detectable on x rays.

In the past, hip replacement surgery was an option primarily for people over 60 years of age. Typically, older people are less active and put less strain on the artificial hip than do younger, more active people. In recent years, however, doctors have found that hip replacement surgery can be very successful in younger people as well. New technology has improved the artificial parts, allowing them to withstand more stress and strain. A more important factor than age in determining the success of hip replacement is the overall health and activity level of the patient.

For some people who would otherwise qualify, hip replacement may be problematic. For example, people who suffer from severe muscle weakness or Parkinson’s disease are more likely than healthy people to damage or dislocate an artificial hip. Because people who are at high risk for infections or in poor health are less likely to recover successfully, doctors may not recommend hip replacement surgery for these patients.

Is a Cemented or Uncemented Prosthesis Better?

Cemented prostheses were developed 40 years ago. Uncemented prostheses were developed about 20 years ago to try to avoid the possibility of loosening parts and the breaking off of cement particles, which sometimes happen in the cemented replacement. Because each person’s condition is unique, the doctor and patient must weigh the advantages and disadvantages to decide which type of prosthesis is better.

The primary disadvantage of an uncemented prosthesis is the extended recovery period. Because it takes a long time for the natural bone to grow and attach to the prosthesis, people with uncemented replacements must limit activities for up to 3 months to protect the hip joint. The process of natural bone growth also can cause thigh pain for several months after the surgery.

Research has proven the effectiveness of cemented prostheses to reduce pain and increase joint mobility. These results usually are noticeable immediately after surgery. Cemented replacements are more frequently used than cementless ones for older, less active people and people with weak bones, such as those who have osteoporosis.