Whether you have just begun exploring treatment options or have already decided with your orthopaedic surgeon to undergo hip replacement surgery, this information will help you understand the benefits and limitations of total hip replacement. This article describes how a normal hip works, the causes of hip pain, what to expect from hip replacement surgery, and what exercises and activities will help restore your mobility and strength and enable you to return to everyday activities.

If your hip has been damaged by arthritis, a fracture or other conditions, common activities such as walking or getting in and out of a chair may be painful and difficult. Your hip may be stiff and it may be hard to put on your shoes and socks. You may even feel uncomfortable while resting.

If medications, changes in your everyday activities, and the use of walking aids such as a cane are not helpful, you may want to consider hip replacement surgery. By replacing your diseased hip joint with an artificial joint, hip replacement surgery can relieve your pain, increase motion, and help you get back to enjoying normal, everyday activities.

First performed in 1960, hip replacement surgery is one of the most important surgical advances of the last century. Since 1960, improvements in joint replacement surgical techniques and technology have greatly increased the effectiveness of total hip replacement. Today, more than 193,000 total hip replacements are performed each year in the United States. Similar surgical procedures are performed on other joints, including the knee, shoulder, and elbow.

The hip is one of the body's largest weight-bearing joints. It consists of two main parts: a ball (femoral head) at the top of your thighbone (femur) that fits into a rounded socket (acetabulum) in your pelvis. Bands of tissue called ligaments (hip capsule) connect the ball to the socket and provide stability to the joint.

The bone surfaces of the ball and socket have a smooth durable cover of articular cartilage that cushions the ends of the bones and enables them to move easily.

A thin, smooth tissue called synovial membrane covers all remaining surfaces of the hip joint. In a healthy hip, this membrane makes a small amount of fluid that lubricates and almost eliminates friction in your hip joint.

Normally, all of these parts of your hip work in harmony, allowing you to move easily and without pain.

The most common cause of chronic hip pain and disability is arthritis. Osteoarthritis, rheumatoid arthritis, and traumatic arthritis are the most common forms of this disease.

• Osteoarthritis usually occurs in people 50 years of age and older and often individuals with a family history of arthritis. It may be caused or accelerated by subtle irregularities in how the hip developed. In this form of the disease, the articular cartilage cushioning the bones of the hip wears away. The bones then rub against each other, causing hip pain and stiffness.
• Rheumatoid arthritis is an autoimmune disease in which the synovial membrane becomes inflamed, produces too much synovial fluid, and damages the articular cartilage, leading to pain and stiffness.
• Traumatic arthritis can follow a serious hip injury or fracture. A hip fracture can cause a condition known as osteonecrosis. The articular cartilage becomes damaged and, over time, causes hip pain and stiffness.

Whether to have hip replacement surgery should be a cooperative decision made by you, your family, your primary care doctor, and your orthopaedic surgeon. The process of making this decision typically begins with a referral by your doctor to an orthopaedic surgeon for an initial evaluation.

Although many patients who undergo hip replacement surgery are 60 to 80 years of age, orthopaedic surgeons evaluate patients individually. Recommendations for surgery are based on the extent of your pain, disability, and general health status-not solely on age.

You may benefit from hip replacement surgery if:

• Hip pain limits your everyday activities such as walking or bending.
• Hip pain continues while resting, either day or night.
• Stiffness in a hip limits your ability to move or lift your leg.
• You have little pain relief from anti-inflammatory drugs or glucosamine sulfate.
• You have harmful or unpleasant side effects from your hip medications.
• Other treatments such as physical therapy or the use of a gait aid such as a cane do not relieve hip pain.

Your orthopaedic surgeon will review the results of your evaluation with you and discuss whether hip replacement surgery is the best method to relieve your pain and improve your mobility. Other treatment options such as medications, physical therapy, or other types of surgery also may be considered. Your orthopaedic surgeon will explain the potential risks and complications of hip replacement surgery, including those related to the surgery itself and those that can occur over time after your surgery. The orthopaedic evaluation will typically include:

• A medical history, in which your orthopaedic surgeon gathers information about your general health and asks questions about the extent of your hip pain and how it affects your ability to perform every day activities.
• A physical examination to assess hip mobility, strength, and alignment.
• X-rays (radiographs) to determine the extent of damage or deformity in your hip.
• Occasionally, blood tests or other tests such as MRI (magnetic resonance imaging or bone scanning may be needed to determine the condition of the bone and soft tissues of your hip.

An important factor in deciding whether to have hip replacement surgery is understanding what the procedure can and cannot do.

Most people who undergo hip replacement surgery experience a dramatic reduction of hip pain and a significant improvement in their ability to perform the common activities of daily living. However, hip replacement surgery will not enable you to do more than you could before your hip problem developed.

Following surgery, you will be advised to avoid certain activities, including jogging and high-impact sports, for the rest of your life. You may be asked to avoid specific positions of the joint that could lead to dislocation.

Even with normal use and activities, an artificial joint (prosthesis) develops some wear over time. If you participate in high-impact activities or are overweight, this wear may accelerate and cause the prosthesis to loosen and become painful.

You will most likely be admitted to the hospital on the day of your surgery. Prior to admission, a member of the anesthesia team will evaluate you. The most common types of anesthesia for hip replacement surgery are general anesthesia (which puts you to sleep throughout the procedure and uses a machine to help you breath) or spinal anesthesia (which allows you to breath on your own but anesthetizes your body from the waist down). The anesthesia team will discuss these choices with you and help you decide which type of anesthesia is best for you.

The surgical procedure takes a few hours. Your orthopaedic surgeon will remove the damaged cartilage and bone and then position new metal, plastic, or ceramic joint surfaces to restore the alignment and function of your hip.

Many different types of designs and materials are currently used in artificial hip joints. All of them consist of two basic components: the ball component (made of a highly polished strong metal or ceramic material) and the socket component (a durable cup made of plastic, ceramic or metal, which may have an outer metal shell).

Special surgical cement may be used to fill the gap between the prosthesis and remaining natural bone to secure the artificial joint.

A noncemented prosthesis has also been developed and is used most often in younger, more active patients with strong bone. The prosthesis may be coated with textured metal or a special bone-like substance, which allows bone to grow into the prosthesis.

A combination of a cemented ball and a noncemented socket may be used.

Your orthopaedic surgeon will choose the type of prosthesis that best meets your needs.

After surgery, you will be moved to the recovery room where you will remain for 1 to 2 hours while your recovery from anesthesia is monitored. After you awaken fully, you will be taken to your hospital room.

Over the past several years, orthopaedic surgeons have been developing new minimally invasive surgical techniques for inserting total hip replacement implants through smaller incisions.

It is hoped, but not yet proven, that this may allow for quicker, less painful recovery and more rapid return to normal activities. Minimally invasive and small incision total hip replacement surgery is a rapidly evolving area. Although certain techniques have proven to be safe, others may be associated with an increased risk of complications, such as nerve and artery injuries, wound healing problems, infection, fracture of the femur, and malposition of the implants, which can contribute to premature wear, dislocation, and loosening of your hip replacement.

Patients who have marked deformity of the joint, those who are heavy or muscular, and those who have other health problems that can contribute to wound healing problems appear to be at higher risk of problems.

Your orthopaedic surgeon can talk to you about his or her experience with minimally invasive hip replacement surgery and the possible risks and benefits. The AAOS and the American Association of Hip and Knee Surgeons have developed information for patients about minimally invasive hip replacement surgery.

You will usually stay in the hospital for a few days. After surgery, you will feel pain in your hip. Pain medication will be given to make you as comfortable as possible.

To avoid lung congestion after surgery, you will be asked to breathe deeply and cough frequently.

To protect your hip during early recovery, a positioning splint, such as a V-shaped pillow placed between your legs, may be used.

Walking and light activity are important to your recovery and will begin the day of or the day after your surgery. Most patients who undergo total hip replacement begin standing and walking with the help of a walking support and a physical therapist the day after surgery. The physical therapist will teach you specific exercises to strengthen your hip and restore movement for walking and other normal daily activities.

The complication rate following hip replacement surgery is low. Serious complications, such as joint infection, occur in fewer than 2% of patients. Major medical complications, such as heart attack or stroke, occur even less frequently. However, chronic illnesses may increase the potential for complications. Although uncommon, when these complications occur they can prolong or limit full recovery.

Blood clots in the leg veins or pelvis are the most common complication of hip replacement surgery. Your orthopaedic surgeon may prescribe one or more measures to prevent blood clots from forming in your leg veins or, if they do form, measures to prevent them from becoming symptomatic. These measures may include special support hose, inflatable leg coverings, ankle pump exercises, and blood thinners.

Leg-length inequality may occur or may become or seem worse after hip replacement. Your orthopaedic surgeon will take this into account, in addition to other issues, including the stability and biomechanics of the hip. Some patients may feel more comfortable with a shoe lift after surgery.

Other complications such as dislocation, nerve and blood vessel injury, bleeding, fracture, and stiffness can occur. In a small number of patients, some pain can continue or new pain can occur after surgery.

Over years, the hip prosthesis may wear out or loosen. This problem will likely be less common with newer materials and techniques. When the prosthesis wears, bone loss may occur because of the small particles produced at the wearing surface. This process is called osteolysis.

The success of your surgery will depend in large measure on how well you follow your orthopaedic surgeon's instructions regarding home care during the first few weeks after surgery.

The most common causes of infection following hip replacement surgery are from bacteria that enter the bloodstream during dental procedures, urinary tract infections, or skin infections. These bacteria can lodge around your prosthesis.

Following your surgery, you may need to take antibiotics prior to dental work, including dental cleanings, or any surgical procedure that could allow bacteria to enter your bloodstream. For many people with joint replacements and normal immune systems, the American Academy of Orthopaedic Surgeons (AAOS) recommends antibiotic prophylaxis before dental work.

Warning signs of a possible hip replacement infection are:

• Persistent fever (higher than 100°F orally)
• Shaking chills
• Increasing redness, tenderness, or swelling of the hip wound
• Drainage from the hip wound
• Increasing hip pain with both activity and rest

Notify your doctor immediately if you develop any of these signs.

A fall during the first few weeks after surgery can damage your new hip and may result in a need for more surgery. Stairs are a particular hazard until your hip is strong and mobile. You should use a cane, crutches, a walker, or handrails or have someone help you until you improve your balance, flexibility, and strength.

Your orthopaedic surgeon and physical therapist will help you decide which assistive aides will be required following surgery, and when those aides can safely be discontinued.

To assure proper recovery and prevent dislocation of the prosthesis, you must take special precautions:

• Do not cross your legs.
• Do not bend your hips more than a right angle (90°).
• Do not turn your feet excessively inward or outward.
• Use a pillow between your legs at night when sleeping until you are advised by your orthopaedic surgeon that you can remove it.

Your surgeon and physical therapist will give you more instructions prior to your discharge from the hospital.

You may feel some numbness in the skin around your incision. You also may feel some stiffness, particularly with excessive bending. These differences often diminish with time, and most patients find these are minor compared with the pain and limited function they experienced prior to surgery.

Your new hip may activate metal detectors required for security in airports and some buildings. Tell the security agent about your hip replacement if the alarm is activated. You may ask your orthopaedic surgeon for a card confirming that you have an artificial hip.

After surgery, make sure you also do the following:

• Participate in a regular light exercise program to maintain proper strength and mobility of your new hip.
• Take special precautions to avoid falls and injuries. Individuals who have undergone hip replacement surgery and experience a fracture may require more surgery.
• Notify your dentist that you have had a hip replacement. You will need to take antibiotics before any dental procedure. Information for your surgeon regarding the use of antibiotics is available from the AAOS.
• See your orthopaedic surgeon periodically for routine follow-up examinations and x-rays (radiographs), even if your hip replacement seems to be doing fine.

Your orthopaedic surgeon is a medical doctor with extensive training in the diagnosis and nonsurgical and surgical treatment of the musculoskeletal system, including bones, joints, ligaments, tendons, muscles, and nerves.

This information has been prepared by the American Academy of Orthopaedic Surgeons and is intended to contain current information on the subject from recognized authorities. However, it does not represent official policy of the AAOS and its text should not be construed as excluding other acceptable viewpoints. Persons with questions about a medical condition should consult a physician who is informed about the condition and the various modes of treatment available.