It’s hip to have a new hip

Hip replacement surgery can be a godsend for people who have been hobbled by an arthritic hip. But the operation is almost never an urgent necessity. It makes sense only if debilitating pain persists despite the use of physical therapy, anti-inflammatory medications, weight loss, and other conservative treatments.

But even if you’re conscientious about performing prescribed exercises and using other non-surgical strategies, your hip joint may continue to deteriorate. You may reach the point where you have a difficult time getting around even with a cane – and you worry that a walker or wheelchair may be next. This is the time to ask an orthopedic surgeon about hip replacement.

Who Benefits?

People in their 60s and 70s were once the primary beneficiaries of total hip replacement (THR) which has been relieving pain in people with severe osteoarthritis of the hip since 1960. Today, however, THR is an option for adults of any age, whether in their 90s, 50s, or younger – thanks to advances in surgery, rehabilitation, and the design of the implant used to replace the diseased hip. A study in the March 2003 issue of Mayo Clinic Proceedings found that THR was reliable, durable, and safe in elderly patients (average age 92) who underwent surgery between 1970 and 1997. Other studies have produced similar findings in both older and younger adults.

Every year, in the United States alone, about 170,000 THRs are performed in adults aged 20 to 100. Virtually everyone who undergoes the procedure can walk farther and faster than they could before surgery. Although THR cannot restore the ability to run or participate in other high-impact activities or contact sports, otherwise healthy, well-motivated THR patients nearly always can – and should – resume low-impact activities, including brisk walking, cycling, swimming, hiking, doubles tennis, golfing, and bowling. In elderly patients, THR often restores functional independence.

The Procedure

Your natural hip joint is a ball-and-socket arrangement consisting of a cup-like structure (acetabulum, or "socket") in the pelvis and the rounded head of the thigh bone (femur, or the "ball"). Hip replacement surgery involves cutting away the damaged bone and cartilage and then fitting, positioning, and securing the artificial hip (see illustration).

The hip prosthesis can be secured with special glue (a cemented procedure) or by using a ball and socket with a porous coating that allows bone to grow into the artificial parts (cementless procedure). In a "hybrid" procedure, the socket is fixed with the porous material, and the ball is cemented in place. Cementless procedures typically hold up better over the long term, but they aren’t appropriate for everyone.

Many hip replacement surgeries can be performed under regional anesthesia and takes about two hours. Potential complications include infection and formation of blood clots (deep vein thrombosis), but the percentage of patients who experience these problems is low.

Dislocation of your new hip is another concern during the recovery period. The components of the artificial hip are smaller than those of the natural hip, and the ball can become dislodged with certain body movements. In the hospital, you will be shown how to avoid unsafe movements while your hip is healing.

Recovery And Rehabilitation

On the first post-operative day, most patients can stand by the bedside and are ready to begin some simple hip-strengthening exercises. By the second day after surgery, you probably will be walking with assistance, using a walker or crutches. During your hospital stay, a specialist in Physical Medication and Rehabilitation (physiatrist) will evaluate you and prescribe a program of exercises and functional mobilization. A physical therapist, working with your doctors, will teach you how to sit, rise from a chair, go up and down stairs, and get in and out of a bathtub or car, and perform other daily activities. The therapist also will give you additional prescribed exercises to increase the strength and flexibility of your hip. These exercises must be continued at home. Depending on your medical recovery and mobility, you may go home as early as three to four days after surgery.

You can expect to use a walker or crutches for about three weeks and then switch to full weight bearing with the use of a cane. Most patients would not need a cane indoors after about four to five weeks and are off all external support in six to eight weeks.

Life With A New Hip

Patients who undergo THR require life-long follow-up care aimed primarily at protecting and monitoring the integrity of the prosthesis, which normally lasts 15 to 20 years. Staying active is important to maintain the gains achieved through surgery. But overuse may speed implant failure, which can be highly painful and difficult to repair. The specific activities permitted depend on each patient’s general health, fitness, motivation, and familiarity with the activity. Professional guidance about how to exercise is important because, unlike a normal hip, the prosthesis does not contain nerves that can send pain signals warning of possible damage.

A physical examination and x-ray studies should be performed every 12 to 18 months. If loosening or other evidence that the prosthesis may fail is discovered, the prosthesis should be removed and replaced. This procedure, known as revision surgery, is nearly always successful. However, the results are generally not as good as they are after the initial procedure. The need for revision surgery can be delayed or eliminated by postponing the initial THR until hip pain significantly interferes with daily life and walking distance decreases to about a mile or less. Many experts endorse these criteria.

Although osteoarthritis is the most common reason for THR, the procedure can relieve chronic hip pain due to rheumatoid arthritis, bone tumors, and certain other underlying causes. THR is used less frequently for hip fractures, which are more often repaired with plates, screws, and pins rather than an entirely new artificial joint.

Risk Factors

A study published in the February 2003 issue of the American Journal of Medicine, based on data from the Nurses Health Study, a large-scale, long-term population study, examined the risk factors for THR in 568 female nurses who underwent the procedure for osteoarthritis after 1990. The two clearest indicators of risk were advanced age and long-term obesity. This study found no association between THR and recreational physical activity, smoking, alcohol use, or hormone replacement therapy.

Chronic medical problems are not usually an obstacle to THR. Heart disease, diabetes, and chronic obstructive lung disease (emphysema or chronic bronchitis) rarely cause the procedure to be postponed. THR can even be performed in people with bone quality and density that are significantly compromised by osteoporosis. Medical problems that may delay surgery include active infections, uncontrolled hypertension, or unstable chronic obstructive pulmonary disease.

The Future

The traditional replacement prosthesis consists of a hard metal (usually a cobalt-chromium alloy) ball that fits into a hard plastic (polyethylene, to be precise) cup. The major drawback has been the wear on the plastic cup. About 5 years ago, they started to make implants with "cross-linked" polyethylene, which is supposed to hold up better.

Newer alternatives to the metal-on-plastic design include ceramic-on-ceramic (which is what Jack Nicklaus had) and metal-on-metal versions. Most surgeons believe that these two alternatives are more durable than the conventional implant, even if the cross-linked polyethylene is an improvement. Perhaps the main drawback is cost. For example, a ceramic-on ceramic implant is twice as expensive as a conventional metal-on-plastic implant. So the conservative approach at present is to reserve the longer-lasting, more expensive implants for younger and more active patients and to stick with the conventional design for older and less active people.

However, whatever hip prosthesis is used, the bottom line is this: If the arthritis in your hip is interfering with your day-to-day activities, or the pain has become unbearable, hip replacement surgery can help you reclaim your life. For such people, it’s hip to have a new hip!