Last updated: 11/24/2009

Because pain in the hip joint is usually a gradual development, its cause has been diagnosed in most cases by the time the patient is ready to consider hip replacement surgery. The doctor will have taken a careful medical

/> and employment history in order to determine the most likely cause of the pain and whether the patient's job may be a factor. The doctor will also ask about a family history of osteoarthritis as well as other disorders known to run in families. The patient will be asked about injuries, falls, or other accidents that may have affected the hip joint; and about his or her use of alcohol and prescription medications—particularly steroids, which can cause avascular necrosis.

The patient will then be given a complete physical examination to evaluate his or her fitness for surgery. Certain disorders, including Parkinson's disease; dementia and other conditions of altered mental status; kidney disease; advanced osteoporosis; disorders associated with muscle weakness; diabetes; and an unstable cardiovascular system are generally considered contraindications to hip replacement surgery. People with weakened immune systems may also be advised against surgery. In the case of obesity, the operation may be postponed until the patient loses weight. The stress placed on the hip joint during normal walking can be as high as three times the patient's body weight; thus each pound in weight reduction equals three pounds in stress reduction. Consequently, weight reduction lowers an obese patient's risk of complications after the operation.

The doctor will also order a radiograph, or x ray, of the affected hip. The results will show the location and extent of damage to the hip joint.

Diagnostic tests

The doctor may also order one or more specialized tests, depending on the known or suspected causes of the pain:

• Aspiration. Aspiration is a procedure in which fluid is withdrawn from the joint by a needle and sent to a laboratory for analysis. It is done to check for infection in the joint.
• Arthrogram. An arthrogram is a special type of x ray in which a contrast dye is injected into the hip to outline the cavity surrounding the joint.
• Magnetic resonance imaging (MRI). An MRI uses a large magnet, radio waves, and a computer to generate images of the head and back. It is helpful in diagnosing avascular necrosis.
• Computed tomography (CAT) scan. A CAT scan is another specialized type of x ray that uses computers to generate three-dimensional images of the hip joint. It is most often used to evaluate the severity of avascular necrosis and to obtain a more accurate picture of malformed or unusually shaped joints.
• Bone densitometry test. This test measures the density or strength of the patient's bones. It does not require injections; the patient lies flat on a padded table while an imager passes overhead. This test is most often given to patients at risk for osteoporosis or other disorders that affect bone density.

Preoperative preparation

Hip replacement surgery requires extensive and detailed preparation on the patient's part because it affects so many aspects of life.

LEGAL AND FINANCIAL CONSIDERATIONS. In the United States, physicians and hospitals are required to verify the patient's insurance benefits before surgery and to obtain precertification from the patient's insurer or from Medicare. Without health insurance, the total cost of a hip replacement as of 2002 can run as high as $35,000–$45,000. In addition to insurance documentation, patients are legally required to sign an informed consent form prior to surgery. Informed consent essentially signifies that the patient is a knowledgeable participant in making healthcare decisions. The doctor will discuss all of the following with the patient before he or she signs the form: the nature of the surgery; reasonable alternatives to the surgery; and the risks, benefits, and uncertainties of each option. Informed consent also requires the doctor to make sure that the patient understands the information that has been given.

MEDICAL CONSIDERATIONS. Patients are asked to do the following in preparation for hip replacement surgery:

• Get in shape physically by doing exercises for strengthening the heart and lungs, building up the muscles around the hip, and increasing the range of motion of the hip joint. Many clinics and hospitals distribute illustrated pamphlets of preoperation exercises.
• Loose weight if the surgeon recommends it.
• Quit smoking. Smoking weakens the cardiovascular system and increases the risks that the patient will have breathing difficulties under anesthesia.
• Make donations of one's own blood for storage in case a transfusion is necessary during surgery. This procedure is known as autologous blood donation; it has the advantage of avoiding the risk of transfusion reactions or transmission of diseases from infected blood donors.
• Have necessary dental work completed before the operation. This precaution is necessary because small numbers of bacteria enter the bloodstream whenever a dentist performs any procedure that causes the gums to bleed. Bacteria from the mouth can be carried to the site of the hip replacement and cause an infection.
• Discontinue taking birth control pills and any anti-inflammatory medications (aspirin or NSAIDs) two weeks before surgery. Most doctors also recommend discontinuing any alternative herbal preparations at this time, as some of them interact with anesthetics and pain medications.

LIFESTYLE CHANGES. Hip replacement surgery requires a long period of recovery at home after leaving the hospital. Since the patient's physical mobility will be limited, he or she should do the following before the operation:

• Arrange for leave from work, help at home, help with driving, and similar tasks and commitments.
• Obtain a handicapped parking permit.
• Check the house or apartment living quarters thoroughly for needed adjustments to furniture, appliances, lighting, and personal conveniences. People recovering from hip replacement surgery must minimize bending, stooping, and any risk of falling. There are several good guides available that describe household safety and comfort considerations in detail.
• Stock up on nonperishable groceries, cleaning supplies, and similar items in order to minimize shopping.
• Have a supply of easy-care clothing with elastic waistbands and simple fasteners in front rather than complicated ties or buttons in the back. Shoes should be slipons or fastened with Velcro.

Many hospitals and clinics now have "preop" classes for patients scheduled for hip replacement surgery. These classes answer questions regarding preparation for the operation and what to expect during recovery, but in addition they provide opportunities for patients to share concerns and experiences. Studies indicate that patients who have attended preop classes are less anxious before surgery and generally recover more rapidly.